On bpf(BPF_PROG_LOAD) syscall user-supplied BPF programs are translated by the verifier into "xlated" BPF programs. During this process the original instructions offsets might be adjusted and/or individual instructions might be replaced by new sets of instructions, or deleted. Add a new BPF map type which is aimed to keep track of how, for a given program, the original instructions were relocated during the verification. Also, besides keeping track of the original -> xlated mapping, make x86 JIT to build the xlated -> jitted mapping for every instruction listed in an instruction array. This is required for every future application of instruction arrays: static keys, indirect jumps and indirect calls. A map of the BPF_MAP_TYPE_INSN_ARRAY type must be created with a u32 keys and value of size 8. The values have different semantics for userspace and for BPF space. For userspace a value consists of two u32 values – xlated and jitted offsets. For BPF side the value is a real pointer to a jitted instruction. On map creation/initialization, before loading the program, each element of the map should be initialized to point to an instruction offset within the program. Before the program load such maps should be made frozen. After the program verification xlated and jitted offsets can be read via the bpf(2) syscall. If a tracked instruction is removed by the verifier, then the xlated offset is set to (u32)-1 which is considered to be too big for a valid BPF program offset. One such a map can, obviously, be used to track one and only one BPF program. If the verification process was unsuccessful, then the same map can be re-used to verify the program with a different log level. However, if the program was loaded fine, then such a map, being frozen in any case, can't be reused by other programs even after the program release. Example. Consider the following original and xlated programs: Original prog: Xlated prog: 0: r1 = 0x0 0: r1 = 0 1: *(u32 *)(r10 - 0x4) = r1 1: *(u32 *)(r10 -4) = r1 2: r2 = r10 2: r2 = r10 3: r2 += -0x4 3: r2 += -4 4: r1 = 0x0 ll 4: r1 = map[id:88] 6: call 0x1 6: r1 += 272 7: r0 = *(u32 *)(r2 +0) 8: if r0 >= 0x1 goto pc+3 9: r0 <<= 3 10: r0 += r1 11: goto pc+1 12: r0 = 0 7: r6 = r0 13: r6 = r0 8: if r6 == 0x0 goto +0x2 14: if r6 == 0x0 goto pc+4 9: call 0x76 15: r0 = 0xffffffff8d2079c0 17: r0 = *(u64 *)(r0 +0) 10: *(u64 *)(r6 + 0x0) = r0 18: *(u64 *)(r6 +0) = r0 11: r0 = 0x0 19: r0 = 0x0 12: exit 20: exit An instruction array map, containing, e.g., instructions [0,4,7,12] will be translated by the verifier to [0,4,13,20]. A map with index 5 (the middle of 16-byte instruction) or indexes greater than 12 (outside the program boundaries) would be rejected. The functionality provided by this patch will be extended in consequent patches to implement BPF Static Keys, indirect jumps, and indirect calls. Signed-off-by: Anton Protopopov Reviewed-by: Eduard Zingerman --- arch/x86/net/bpf_jit_comp.c | 3 + include/linux/bpf.h | 15 ++ include/linux/bpf_types.h | 1 + include/linux/bpf_verifier.h | 2 + include/uapi/linux/bpf.h | 21 +++ kernel/bpf/Makefile | 2 +- kernel/bpf/bpf_insn_array.c | 289 +++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 22 +++ kernel/bpf/verifier.c | 43 +++++ tools/include/uapi/linux/bpf.h | 21 +++ 10 files changed, 418 insertions(+), 1 deletion(-) create mode 100644 kernel/bpf/bpf_insn_array.c diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index d4c93d9e73e4..73a3055d59df 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -3827,6 +3827,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) jit_data->header = header; jit_data->rw_header = rw_header; } + + bpf_prog_update_insn_ptrs(prog, addrs, image); + /* * ctx.prog_offset is used when CFI preambles put code *before* * the function. See emit_cfi(). For FineIBT specifically this code diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a47d67db3be5..9d41a6affcef 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3797,4 +3797,19 @@ int bpf_prog_get_file_line(struct bpf_prog *prog, unsigned long ip, const char * const char **linep, int *nump); struct bpf_prog *bpf_prog_find_from_stack(void); +int bpf_insn_array_init(struct bpf_map *map, const struct bpf_prog *prog); +int bpf_insn_array_ready(struct bpf_map *map); +void bpf_insn_array_release(struct bpf_map *map); +void bpf_insn_array_adjust(struct bpf_map *map, u32 off, u32 len); +void bpf_insn_array_adjust_after_remove(struct bpf_map *map, u32 off, u32 len); + +#ifdef CONFIG_BPF_SYSCALL +void bpf_prog_update_insn_ptrs(struct bpf_prog *prog, u32 *offsets, void *image); +#else +static inline void +bpf_prog_update_insn_ptrs(struct bpf_prog *prog, u32 *offsets, void *image) +{ +} +#endif + #endif /* _LINUX_BPF_H */ diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index fa78f49d4a9a..b13de31e163f 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -133,6 +133,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_RINGBUF, ringbuf_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_BLOOM_FILTER, bloom_filter_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_USER_RINGBUF, user_ringbuf_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_ARENA, arena_map_ops) +BPF_MAP_TYPE(BPF_MAP_TYPE_INSN_ARRAY, insn_array_map_ops) BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint) BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index c6eb68b6389c..6b820d8d77af 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -754,8 +754,10 @@ struct bpf_verifier_env { struct list_head free_list; /* list of struct bpf_verifier_state_list */ struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */ struct btf_mod_pair used_btfs[MAX_USED_BTFS]; /* array of BTF's used by BPF program */ + struct bpf_map *insn_array_maps[MAX_USED_MAPS]; /* array of INSN_ARRAY map's to be relocated */ u32 used_map_cnt; /* number of used maps */ u32 used_btf_cnt; /* number of used BTF objects */ + u32 insn_array_map_cnt; /* number of used maps of type BPF_MAP_TYPE_INSN_ARRAY */ u32 id_gen; /* used to generate unique reg IDs */ u32 hidden_subprog_cnt; /* number of hidden subprogs */ int exception_callback_subprog; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 1d73f165394d..f5713f59ac10 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1026,6 +1026,7 @@ enum bpf_map_type { BPF_MAP_TYPE_USER_RINGBUF, BPF_MAP_TYPE_CGRP_STORAGE, BPF_MAP_TYPE_ARENA, + BPF_MAP_TYPE_INSN_ARRAY, __MAX_BPF_MAP_TYPE }; @@ -7649,4 +7650,24 @@ enum bpf_kfunc_flags { BPF_F_PAD_ZEROS = (1ULL << 0), }; +/* + * Values of a BPF_MAP_TYPE_INSN_ARRAY entry must be of this type. + * + * Before the map is used the orig_off field should point to an + * instruction inside the program being loaded. The other fields + * must be set to 0. + * + * After the program is loaded, the xlated_off will be adjusted + * by the verifier to point to the index of the original instruction + * in the xlated program. If the instruction is deleted, it will + * be set to (u32)-1. The jitted_off will be set to the corresponding + * offset in the jitted image of the program. + */ +struct bpf_insn_array_value { + __u32 orig_off; + __u32 xlated_off; + __u32 jitted_off; + __u32 :32; +}; + #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 7fd0badfacb1..232cbc97434d 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -9,7 +9,7 @@ CFLAGS_core.o += -Wno-override-init $(cflags-nogcse-yy) obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o log.o token.o liveness.o obj-$(CONFIG_BPF_SYSCALL) += bpf_iter.o map_iter.o task_iter.o prog_iter.o link_iter.o obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o bloom_filter.o -obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o +obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o bpf_insn_array.o obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o bpf_task_storage.o obj-${CONFIG_BPF_LSM} += bpf_inode_storage.o obj-$(CONFIG_BPF_SYSCALL) += disasm.o mprog.o diff --git a/kernel/bpf/bpf_insn_array.c b/kernel/bpf/bpf_insn_array.c new file mode 100644 index 000000000000..dc66154466b3 --- /dev/null +++ b/kernel/bpf/bpf_insn_array.c @@ -0,0 +1,289 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2025 Isovalent */ + +#include + +#define MAX_INSN_ARRAY_ENTRIES 256 + +struct bpf_insn_array { + struct bpf_map map; + atomic_t used; + long *ips; + DECLARE_FLEX_ARRAY(struct bpf_insn_array_value, values); +}; + +#define cast_insn_array(MAP_PTR) \ + container_of((MAP_PTR), struct bpf_insn_array, map) + +#define INSN_DELETED ((u32)-1) + +static inline u32 insn_array_alloc_size(u32 max_entries) +{ + const u32 base_size = sizeof(struct bpf_insn_array); + const u32 entry_size = sizeof(struct bpf_insn_array_value); + + return base_size + max_entries * (entry_size + sizeof(long)); +} + +static int insn_array_alloc_check(union bpf_attr *attr) +{ + u32 value_size = sizeof(struct bpf_insn_array_value); + + if (attr->max_entries == 0 || attr->key_size != 4 || + attr->value_size != value_size || attr->map_flags != 0) + return -EINVAL; + + if (attr->max_entries > MAX_INSN_ARRAY_ENTRIES) + return -E2BIG; + + return 0; +} + +static void insn_array_free(struct bpf_map *map) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + + bpf_map_area_free(insn_array); +} + +static struct bpf_map *insn_array_alloc(union bpf_attr *attr) +{ + u64 size = insn_array_alloc_size(attr->max_entries); + struct bpf_insn_array *insn_array; + + insn_array = bpf_map_area_alloc(size, NUMA_NO_NODE); + if (!insn_array) + return ERR_PTR(-ENOMEM); + + /* ips are allocated right after the insn_array->values[] array */ + insn_array->ips = (void *)&insn_array->values[attr->max_entries]; + + bpf_map_init_from_attr(&insn_array->map, attr); + + return &insn_array->map; +} + +static void *insn_array_lookup_elem(struct bpf_map *map, void *key) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + u32 index = *(u32 *)key; + + if (unlikely(index >= insn_array->map.max_entries)) + return NULL; + + return &insn_array->values[index]; +} + +static long insn_array_update_elem(struct bpf_map *map, void *key, void *value, u64 map_flags) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + u32 index = *(u32 *)key; + struct bpf_insn_array_value val = {}; + + if (unlikely(index >= insn_array->map.max_entries)) + return -E2BIG; + + if (unlikely(map_flags & BPF_NOEXIST)) + return -EEXIST; + + copy_map_value(map, &val, value); + if (val.jitted_off || val.xlated_off) + return -EINVAL; + + insn_array->values[index].orig_off = val.orig_off; + + return 0; +} + +static long insn_array_delete_elem(struct bpf_map *map, void *key) +{ + return -EINVAL; +} + +static int insn_array_check_btf(const struct bpf_map *map, + const struct btf *btf, + const struct btf_type *key_type, + const struct btf_type *value_type) +{ + if (!btf_type_is_i32(key_type)) + return -EINVAL; + + if (!btf_type_is_i64(value_type)) + return -EINVAL; + + return 0; +} + +static u64 insn_array_mem_usage(const struct bpf_map *map) +{ + return insn_array_alloc_size(map->max_entries); +} + +BTF_ID_LIST_SINGLE(insn_array_btf_ids, struct, bpf_insn_array) + +const struct bpf_map_ops insn_array_map_ops = { + .map_alloc_check = insn_array_alloc_check, + .map_alloc = insn_array_alloc, + .map_free = insn_array_free, + .map_get_next_key = bpf_array_get_next_key, + .map_lookup_elem = insn_array_lookup_elem, + .map_update_elem = insn_array_update_elem, + .map_delete_elem = insn_array_delete_elem, + .map_check_btf = insn_array_check_btf, + .map_mem_usage = insn_array_mem_usage, + .map_btf_id = &insn_array_btf_ids[0], +}; + +static inline bool is_frozen(struct bpf_map *map) +{ + guard(mutex)(&map->freeze_mutex); + + return map->frozen; +} + +static bool is_insn_array(const struct bpf_map *map) +{ + return map->map_type == BPF_MAP_TYPE_INSN_ARRAY; +} + +static inline bool valid_offsets(const struct bpf_insn_array *insn_array, + const struct bpf_prog *prog) +{ + u32 off; + int i; + + for (i = 0; i < insn_array->map.max_entries; i++) { + off = insn_array->values[i].orig_off; + + if (off >= prog->len) + return false; + + if (off > 0) { + if (prog->insnsi[off-1].code == (BPF_LD | BPF_DW | BPF_IMM)) + return false; + } + } + + return true; +} + +int bpf_insn_array_init(struct bpf_map *map, const struct bpf_prog *prog) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + struct bpf_insn_array_value *values = insn_array->values; + int i; + + if (!is_frozen(map)) + return -EINVAL; + + if (!valid_offsets(insn_array, prog)) + return -EINVAL; + + /* + * There can be only one program using the map + */ + if (atomic_xchg(&insn_array->used, 1)) + return -EBUSY; + + /* + * Reset all the map indexes to the original values. This is needed, + * e.g., when a replay of verification with different log level should + * be performed. + */ + for (i = 0; i < map->max_entries; i++) + values[i].xlated_off = values[i].orig_off; + + return 0; +} + +int bpf_insn_array_ready(struct bpf_map *map) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + int i; + + for (i = 0; i < map->max_entries; i++) { + if (insn_array->values[i].xlated_off == INSN_DELETED) + continue; + if (!insn_array->ips[i]) + return -EFAULT; + } + + return 0; +} + +void bpf_insn_array_release(struct bpf_map *map) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + + atomic_set(&insn_array->used, 0); +} + +void bpf_insn_array_adjust(struct bpf_map *map, u32 off, u32 len) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + int i; + + if (len <= 1) + return; + + for (i = 0; i < map->max_entries; i++) { + if (insn_array->values[i].xlated_off <= off) + continue; + if (insn_array->values[i].xlated_off == INSN_DELETED) + continue; + insn_array->values[i].xlated_off += len - 1; + } +} + +void bpf_insn_array_adjust_after_remove(struct bpf_map *map, u32 off, u32 len) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + int i; + + for (i = 0; i < map->max_entries; i++) { + if (insn_array->values[i].xlated_off < off) + continue; + if (insn_array->values[i].xlated_off == INSN_DELETED) + continue; + if (insn_array->values[i].xlated_off < off + len) + insn_array->values[i].xlated_off = INSN_DELETED; + else + insn_array->values[i].xlated_off -= len; + } +} + +/* + * This function is called by JITs. The image is the real program + * image, the offsets array set up the xlated -> jitted mapping. + */ +void bpf_prog_update_insn_ptrs(struct bpf_prog *prog, u32 *offsets, void *image) +{ + struct bpf_insn_array *insn_array; + struct bpf_map *map; + u32 xlated_off; + int i, j; + + if (!offsets || !image) + return; + + for (i = 0; i < prog->aux->used_map_cnt; i++) { + map = prog->aux->used_maps[i]; + if (!is_insn_array(map)) + continue; + + insn_array = cast_insn_array(map); + for (j = 0; j < map->max_entries; j++) { + xlated_off = insn_array->values[j].xlated_off; + if (xlated_off == INSN_DELETED) + continue; + if (xlated_off < prog->aux->subprog_start) + continue; + xlated_off -= prog->aux->subprog_start; + if (xlated_off >= prog->len) + continue; + + insn_array->values[j].jitted_off = offsets[xlated_off]; + insn_array->ips[j] = (long)(image + offsets[xlated_off]); + } + } +} diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8a129746bd6c..f62d61b6730a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1493,6 +1493,7 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr) case BPF_MAP_TYPE_STRUCT_OPS: case BPF_MAP_TYPE_CPUMAP: case BPF_MAP_TYPE_ARENA: + case BPF_MAP_TYPE_INSN_ARRAY: if (!bpf_token_capable(token, CAP_BPF)) goto put_token; break; @@ -2853,6 +2854,23 @@ static int bpf_prog_verify_signature(struct bpf_prog *prog, union bpf_attr *attr return err; } +static int bpf_prog_mark_insn_arrays_ready(struct bpf_prog *prog) +{ + int err; + int i; + + for (i = 0; i < prog->aux->used_map_cnt; i++) { + if (prog->aux->used_maps[i]->map_type != BPF_MAP_TYPE_INSN_ARRAY) + continue; + + err = bpf_insn_array_ready(prog->aux->used_maps[i]); + if (err) + return err; + } + + return 0; +} + /* last field in 'union bpf_attr' used by this command */ #define BPF_PROG_LOAD_LAST_FIELD keyring_id @@ -3082,6 +3100,10 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) if (err < 0) goto free_used_maps; + err = bpf_prog_mark_insn_arrays_ready(prog); + if (err < 0) + goto free_used_maps; + err = bpf_prog_alloc_id(prog); if (err) goto free_used_maps; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 542e23fb19c7..dd597ea80d99 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10086,6 +10086,8 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, func_id != BPF_FUNC_map_push_elem) goto error; break; + case BPF_MAP_TYPE_INSN_ARRAY: + goto error; default: break; } @@ -20551,6 +20553,15 @@ static int __add_used_map(struct bpf_verifier_env *env, struct bpf_map *map) env->used_maps[env->used_map_cnt++] = map; + if (map->map_type == BPF_MAP_TYPE_INSN_ARRAY) { + err = bpf_insn_array_init(map, env->prog); + if (err) { + verbose(env, "Failed to properly initialize insn array\n"); + return err; + } + env->insn_array_maps[env->insn_array_map_cnt++] = map; + } + return env->used_map_cnt - 1; } @@ -20797,6 +20808,33 @@ static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len } } +static void release_insn_arrays(struct bpf_verifier_env *env) +{ + int i; + + for (i = 0; i < env->insn_array_map_cnt; i++) + bpf_insn_array_release(env->insn_array_maps[i]); +} + +static void adjust_insn_arrays(struct bpf_verifier_env *env, u32 off, u32 len) +{ + int i; + + if (len == 1) + return; + + for (i = 0; i < env->insn_array_map_cnt; i++) + bpf_insn_array_adjust(env->insn_array_maps[i], off, len); +} + +static void adjust_insn_arrays_after_remove(struct bpf_verifier_env *env, u32 off, u32 len) +{ + int i; + + for (i = 0; i < env->insn_array_map_cnt; i++) + bpf_insn_array_adjust_after_remove(env->insn_array_maps[i], off, len); +} + static void adjust_poke_descs(struct bpf_prog *prog, u32 off, u32 len) { struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; @@ -20838,6 +20876,7 @@ static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 of } adjust_insn_aux_data(env, new_prog, off, len); adjust_subprog_starts(env, off, len); + adjust_insn_arrays(env, off, len); adjust_poke_descs(new_prog, off, len); return new_prog; } @@ -21021,6 +21060,8 @@ static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt) if (err) return err; + adjust_insn_arrays_after_remove(env, off, cnt); + memmove(aux_data + off, aux_data + off + cnt, sizeof(*aux_data) * (orig_prog_len - off - cnt)); @@ -24840,6 +24881,8 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 adjust_btf_func(env); err_release_maps: + if (ret) + release_insn_arrays(env); if (!env->prog->aux->used_maps) /* if we didn't copy map pointers into bpf_prog_info, release * them now. Otherwise free_used_maps() will release them. diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 1d73f165394d..f5713f59ac10 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1026,6 +1026,7 @@ enum bpf_map_type { BPF_MAP_TYPE_USER_RINGBUF, BPF_MAP_TYPE_CGRP_STORAGE, BPF_MAP_TYPE_ARENA, + BPF_MAP_TYPE_INSN_ARRAY, __MAX_BPF_MAP_TYPE }; @@ -7649,4 +7650,24 @@ enum bpf_kfunc_flags { BPF_F_PAD_ZEROS = (1ULL << 0), }; +/* + * Values of a BPF_MAP_TYPE_INSN_ARRAY entry must be of this type. + * + * Before the map is used the orig_off field should point to an + * instruction inside the program being loaded. The other fields + * must be set to 0. + * + * After the program is loaded, the xlated_off will be adjusted + * by the verifier to point to the index of the original instruction + * in the xlated program. If the instruction is deleted, it will + * be set to (u32)-1. The jitted_off will be set to the corresponding + * offset in the jitted image of the program. + */ +struct bpf_insn_array_value { + __u32 orig_off; + __u32 xlated_off; + __u32 jitted_off; + __u32 :32; +}; + #endif /* _UAPI__LINUX_BPF_H__ */ -- 2.34.1 Add the following selftests for new insn_array map: * Incorrect instruction indexes are rejected * Two programs can't use the same map * BPF progs can't operate the map * no changes to code => map is the same * expected changes when instructions are added * expected changes when instructions are deleted * expected changes when multiple functions are present Signed-off-by: Anton Protopopov Acked-by: Eduard Zingerman --- .../selftests/bpf/prog_tests/bpf_insn_array.c | 409 ++++++++++++++++++ 1 file changed, 409 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c new file mode 100644 index 000000000000..96ee9c9984f1 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c @@ -0,0 +1,409 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +#ifdef __x86_64__ +static int map_create(__u32 map_type, __u32 max_entries) +{ + const char *map_name = "insn_array"; + __u32 key_size = 4; + __u32 value_size = sizeof(struct bpf_insn_array_value); + + return bpf_map_create(map_type, map_name, key_size, value_size, max_entries, NULL); +} + +static int prog_load(struct bpf_insn *insns, __u32 insn_cnt, int *fd_array, __u32 fd_array_cnt) +{ + LIBBPF_OPTS(bpf_prog_load_opts, opts); + + opts.fd_array = fd_array; + opts.fd_array_cnt = fd_array_cnt; + + return bpf_prog_load(BPF_PROG_TYPE_XDP, NULL, "GPL", insns, insn_cnt, &opts); +} + +static void __check_success(struct bpf_insn *insns, __u32 insn_cnt, __u32 *map_in, __u32 *map_out) +{ + struct bpf_insn_array_value val = {}; + int prog_fd = -1, map_fd, i; + + map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, insn_cnt); + if (!ASSERT_GE(map_fd, 0, "map_create")) + return; + + for (i = 0; i < insn_cnt; i++) { + val.orig_off = map_in[i]; + if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem")) + goto cleanup; + } + + if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze")) + goto cleanup; + + prog_fd = prog_load(insns, insn_cnt, &map_fd, 1); + if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)")) + goto cleanup; + + for (i = 0; i < insn_cnt; i++) { + char buf[64]; + + if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem")) + goto cleanup; + + snprintf(buf, sizeof(buf), "val.xlated_off should be equal map_out[%d]", i); + ASSERT_EQ(val.xlated_off, map_out[i], buf); + } + +cleanup: + close(prog_fd); + close(map_fd); +} + +/* + * Load a program, which will not be anyhow mangled by the verifier. Add an + * insn_array map pointing to every instruction. Check that it hasn't changed + * after the program load. + */ +static void check_one_to_one_mapping(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 4), + BPF_MOV64_IMM(BPF_REG_0, 3), + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + __u32 map_in[] = {0, 1, 2, 3, 4, 5}; + __u32 map_out[] = {0, 1, 2, 3, 4, 5}; + + __check_success(insns, ARRAY_SIZE(insns), map_in, map_out); +} + +/* + * Load a program with two patches (get jiffies, for simplicity). Add an + * insn_array map pointing to every instruction. Check how it was changed + * after the program load. + */ +static void check_simple(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64), + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + __u32 map_in[] = {0, 1, 2, 3, 4, 5}; + __u32 map_out[] = {0, 1, 4, 5, 8, 9}; + + __check_success(insns, ARRAY_SIZE(insns), map_in, map_out); +} + +/* + * Verifier can delete code in two cases: nops & dead code. From insn + * array's point of view, the two cases are the same, so test using + * the simplest method: by loading some nops + */ +static void check_deletions(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */ + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */ + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + __u32 map_in[] = {0, 1, 2, 3, 4, 5}; + __u32 map_out[] = {0, -1, 1, -1, 2, 3}; + + __check_success(insns, ARRAY_SIZE(insns), map_in, map_out); +} + +/* + * Same test as check_deletions, but also add code which adds instructions + */ +static void check_deletions_with_functions(void) +{ + struct bpf_insn insns[] = { + BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */ + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64), + BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */ + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2), + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_EXIT_INSN(), + BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */ + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64), + BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */ + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_EXIT_INSN(), + }; + __u32 map_in[] = { 0, 1, 2, 3, 4, 5, /* func */ 6, 7, 8, 9, 10}; + __u32 map_out[] = {-1, 0, -1, 3, 4, 5, /* func */ -1, 6, -1, 9, 10}; + + __check_success(insns, ARRAY_SIZE(insns), map_in, map_out); +} + +/* + * Try to load a program with a map which points to outside of the program + */ +static void check_out_of_bounds_index(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 4), + BPF_MOV64_IMM(BPF_REG_0, 3), + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int prog_fd, map_fd; + struct bpf_insn_array_value val = {}; + int key; + + map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1); + if (!ASSERT_GE(map_fd, 0, "map_create")) + return; + + key = 0; + val.orig_off = ARRAY_SIZE(insns); /* too big */ + if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &key, &val, 0), 0, "bpf_map_update_elem")) + goto cleanup; + + if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze")) + goto cleanup; + + prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1); + if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)")) { + close(prog_fd); + goto cleanup; + } + +cleanup: + close(map_fd); +} + +/* + * Try to load a program with a map which points to the middle of 16-bit insn + */ +static void check_mid_insn_index(void) +{ + struct bpf_insn insns[] = { + BPF_LD_IMM64(BPF_REG_0, 0), /* 2 x 8 */ + BPF_EXIT_INSN(), + }; + int prog_fd, map_fd; + struct bpf_insn_array_value val = {}; + int key; + + map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1); + if (!ASSERT_GE(map_fd, 0, "map_create")) + return; + + key = 0; + val.orig_off = 1; /* middle of 16-byte instruction */ + if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &key, &val, 0), 0, "bpf_map_update_elem")) + goto cleanup; + + if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze")) + goto cleanup; + + prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1); + if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)")) { + close(prog_fd); + goto cleanup; + } + +cleanup: + close(map_fd); +} + +static void check_incorrect_index(void) +{ + check_out_of_bounds_index(); + check_mid_insn_index(); +} + +/* Once map was initialized, it should be frozen */ +static void check_load_unfrozen_map(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int prog_fd = -1, map_fd; + struct bpf_insn_array_value val = {}; + int i; + + map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, ARRAY_SIZE(insns)); + if (!ASSERT_GE(map_fd, 0, "map_create")) + return; + + for (i = 0; i < ARRAY_SIZE(insns); i++) { + val.orig_off = i; + if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem")) + goto cleanup; + } + + prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1); + if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)")) + goto cleanup; + + /* correctness: now freeze the map, the program should load fine */ + + if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze")) + goto cleanup; + + prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1); + if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)")) + goto cleanup; + + for (i = 0; i < ARRAY_SIZE(insns); i++) { + if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem")) + goto cleanup; + + ASSERT_EQ(val.xlated_off, i, "val should be equal i"); + } + +cleanup: + close(prog_fd); + close(map_fd); +} + +/* Map can be used only by one BPF program */ +static void check_no_map_reuse(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int prog_fd = -1, map_fd, extra_fd = -1; + struct bpf_insn_array_value val = {}; + int i; + + map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, ARRAY_SIZE(insns)); + if (!ASSERT_GE(map_fd, 0, "map_create")) + return; + + for (i = 0; i < ARRAY_SIZE(insns); i++) { + val.orig_off = i; + if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem")) + goto cleanup; + } + + if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze")) + goto cleanup; + + prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1); + if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)")) + goto cleanup; + + for (i = 0; i < ARRAY_SIZE(insns); i++) { + if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem")) + goto cleanup; + + ASSERT_EQ(val.xlated_off, i, "val should be equal i"); + } + + extra_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1); + if (!ASSERT_EQ(extra_fd, -EBUSY, "program should have been rejected (extra_fd != -EBUSY)")) + goto cleanup; + + /* correctness: check that prog is still loadable without fd_array */ + extra_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0); + if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD): expected no error")) + goto cleanup; + +cleanup: + close(extra_fd); + close(prog_fd); + close(map_fd); +} + +static void check_bpf_no_lookup(void) +{ + struct bpf_insn insns[] = { + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), + BPF_EXIT_INSN(), + }; + int prog_fd = -1, map_fd; + + map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1); + if (!ASSERT_GE(map_fd, 0, "map_create")) + return; + + insns[0].imm = map_fd; + + if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze")) + goto cleanup; + + prog_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0); + if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)")) + goto cleanup; + + /* correctness: check that prog is still loadable with normal map */ + close(map_fd); + map_fd = map_create(BPF_MAP_TYPE_ARRAY, 1); + insns[0].imm = map_fd; + prog_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0); + if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)")) + goto cleanup; + +cleanup: + close(prog_fd); + close(map_fd); +} + +static void check_bpf_side(void) +{ + check_bpf_no_lookup(); +} + +static void __test_bpf_insn_array(void) +{ + /* Test if offsets are adjusted properly */ + + if (test__start_subtest("one2one")) + check_one_to_one_mapping(); + + if (test__start_subtest("simple")) + check_simple(); + + if (test__start_subtest("deletions")) + check_deletions(); + + if (test__start_subtest("deletions-with-functions")) + check_deletions_with_functions(); + + /* Check all kinds of operations and related restrictions */ + + if (test__start_subtest("incorrect-index")) + check_incorrect_index(); + + if (test__start_subtest("load-unfrozen-map")) + check_load_unfrozen_map(); + + if (test__start_subtest("no-map-reuse")) + check_no_map_reuse(); + + if (test__start_subtest("bpf-side-ops")) + check_bpf_side(); +} +#else +static void __test_bpf_insn_array(void) +{ + test__skip(); +} +#endif + +void test_bpf_insn_array(void) +{ + __test_bpf_insn_array(); +} -- 2.34.1 When bpf_jit_harden is enabled, all constants in the BPF code are blinded to prevent JIT spraying attacks. This happens during JIT phase. Adjust all the related instruction arrays accordingly. Signed-off-by: Anton Protopopov Reviewed-by: Eduard Zingerman --- kernel/bpf/core.c | 20 ++++++++++++++++++++ kernel/bpf/verifier.c | 11 ++++++++++- 2 files changed, 30 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index d595fe512498..4b62a03d6df5 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1450,6 +1450,23 @@ void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) bpf_prog_clone_free(fp_other); } +static void adjust_insn_arrays(struct bpf_prog *prog, u32 off, u32 len) +{ +#ifdef CONFIG_BPF_SYSCALL + struct bpf_map *map; + int i; + + if (len <= 1) + return; + + for (i = 0; i < prog->aux->used_map_cnt; i++) { + map = prog->aux->used_maps[i]; + if (map->map_type == BPF_MAP_TYPE_INSN_ARRAY) + bpf_insn_array_adjust(map, off, len); + } +#endif +} + struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) { struct bpf_insn insn_buff[16], aux[2]; @@ -1505,6 +1522,9 @@ struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) clone = tmp; insn_delta = rewritten - 1; + /* Instructions arrays must be updated using absolute xlated offsets */ + adjust_insn_arrays(clone, prog->aux->subprog_start + i, rewritten); + /* Walk new program and skip insns we just inserted. */ insn = clone->insnsi + i + insn_delta; insn_cnt += insn_delta; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index dd597ea80d99..2b771e2bf35a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -21601,6 +21601,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) struct bpf_insn *insn; void *old_bpf_func; int err, num_exentries; + int old_len, subprog_start_adjustment = 0; if (env->subprog_cnt <= 1) return 0; @@ -21675,7 +21676,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) func[i]->aux->func_idx = i; /* Below members will be freed only at prog->aux */ func[i]->aux->btf = prog->aux->btf; - func[i]->aux->subprog_start = subprog_start; + func[i]->aux->subprog_start = subprog_start + subprog_start_adjustment; func[i]->aux->func_info = prog->aux->func_info; func[i]->aux->func_info_cnt = prog->aux->func_info_cnt; func[i]->aux->poke_tab = prog->aux->poke_tab; @@ -21729,7 +21730,15 @@ static int jit_subprogs(struct bpf_verifier_env *env) func[i]->aux->might_sleep = env->subprog_info[i].might_sleep; if (!i) func[i]->aux->exception_boundary = env->seen_exception; + + /* + * To properly pass the absolute subprog start to jit + * all instruction adjustments should be accumulated + */ + old_len = func[i]->len; func[i] = bpf_int_jit_compile(func[i]); + subprog_start_adjustment += func[i]->len - old_len; + if (!func[i]->jited) { err = -ENOTSUPP; goto out_free; -- 2.34.1 Add a specific test for instructions arrays with blinding enabled. Signed-off-by: Anton Protopopov Acked-by: Eduard Zingerman --- .../selftests/bpf/prog_tests/bpf_insn_array.c | 95 +++++++++++++++++++ 1 file changed, 95 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c index 96ee9c9984f1..cf852318eeb2 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_insn_array.c @@ -227,6 +227,98 @@ static void check_incorrect_index(void) check_mid_insn_index(); } +static int set_bpf_jit_harden(char *level) +{ + char old_level; + int err = -1; + int fd = -1; + + fd = open("/proc/sys/net/core/bpf_jit_harden", O_RDWR | O_NONBLOCK); + if (fd < 0) { + ASSERT_FAIL("open .../bpf_jit_harden returned %d (errno=%d)", fd, errno); + return -1; + } + + err = read(fd, &old_level, 1); + if (err != 1) { + ASSERT_FAIL("read from .../bpf_jit_harden returned %d (errno=%d)", err, errno); + err = -1; + goto end; + } + + lseek(fd, 0, SEEK_SET); + + err = write(fd, level, 1); + if (err != 1) { + ASSERT_FAIL("write to .../bpf_jit_harden returned %d (errno=%d)", err, errno); + err = -1; + goto end; + } + + err = 0; + *level = old_level; +end: + if (fd >= 0) + close(fd); + return err; +} + +static void check_blindness(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 4), + BPF_MOV64_IMM(BPF_REG_0, 3), + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_MOV64_IMM(BPF_REG_0, 1), + BPF_EXIT_INSN(), + }; + int prog_fd = -1, map_fd; + struct bpf_insn_array_value val = {}; + char bpf_jit_harden = '@'; /* non-exizsting value */ + int i; + + map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, ARRAY_SIZE(insns)); + if (!ASSERT_GE(map_fd, 0, "map_create")) + return; + + for (i = 0; i < ARRAY_SIZE(insns); i++) { + val.orig_off = i; + if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem")) + goto cleanup; + } + + if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze")) + goto cleanup; + + bpf_jit_harden = '2'; + if (set_bpf_jit_harden(&bpf_jit_harden)) { + bpf_jit_harden = '@'; /* open, read or write failed => no write was done */ + goto cleanup; + } + + prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1); + if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)")) + goto cleanup; + + for (i = 0; i < ARRAY_SIZE(insns); i++) { + char fmt[32]; + + if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem")) + goto cleanup; + + snprintf(fmt, sizeof(fmt), "val should be equal 3*%d", i); + ASSERT_EQ(val.xlated_off, i * 3, fmt); + } + +cleanup: + /* restore the old one */ + if (bpf_jit_harden != '@') + set_bpf_jit_harden(&bpf_jit_harden); + + close(prog_fd); + close(map_fd); +} + /* Once map was initialized, it should be frozen */ static void check_load_unfrozen_map(void) { @@ -382,6 +474,9 @@ static void __test_bpf_insn_array(void) if (test__start_subtest("deletions-with-functions")) check_deletions_with_functions(); + if (test__start_subtest("blindness")) + check_blindness(); + /* Check all kinds of operations and related restrictions */ if (test__start_subtest("incorrect-index")) -- 2.34.1 Currently the emit_indirect_jump() function only accepts one of the RAX, RCX, ..., RBP registers as the destination. Make it to accept R8, R9, ..., R15 as well, and make callers to pass BPF registers, not native registers. This is required to enable indirect jumps support in eBPF. Signed-off-by: Anton Protopopov Acked-by: Eduard Zingerman --- arch/x86/net/bpf_jit_comp.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 73a3055d59df..c1f686df6fbc 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -660,24 +660,38 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, #define EMIT_LFENCE() EMIT3(0x0F, 0xAE, 0xE8) -static void emit_indirect_jump(u8 **pprog, int reg, u8 *ip) +static void __emit_indirect_jump(u8 **pprog, int reg, bool ereg) { u8 *prog = *pprog; + if (ereg) + EMIT1(0x41); + + EMIT2(0xFF, 0xE0 + reg); + + *pprog = prog; +} + +static void emit_indirect_jump(u8 **pprog, int bpf_reg, u8 *ip) +{ + u8 *prog = *pprog; + int reg = reg2hex[bpf_reg]; + bool ereg = is_ereg(bpf_reg); + if (cpu_feature_enabled(X86_FEATURE_INDIRECT_THUNK_ITS)) { OPTIMIZER_HIDE_VAR(reg); - emit_jump(&prog, its_static_thunk(reg), ip); + emit_jump(&prog, its_static_thunk(reg + 8*ereg), ip); } else if (cpu_feature_enabled(X86_FEATURE_RETPOLINE_LFENCE)) { EMIT_LFENCE(); - EMIT2(0xFF, 0xE0 + reg); + __emit_indirect_jump(&prog, reg, ereg); } else if (cpu_feature_enabled(X86_FEATURE_RETPOLINE)) { OPTIMIZER_HIDE_VAR(reg); if (cpu_feature_enabled(X86_FEATURE_CALL_DEPTH)) - emit_jump(&prog, &__x86_indirect_jump_thunk_array[reg], ip); + emit_jump(&prog, &__x86_indirect_jump_thunk_array[reg + 8*ereg], ip); else - emit_jump(&prog, &__x86_indirect_thunk_array[reg], ip); + emit_jump(&prog, &__x86_indirect_thunk_array[reg + 8*ereg], ip); } else { - EMIT2(0xFF, 0xE0 + reg); /* jmp *%\reg */ + __emit_indirect_jump(&prog, reg, ereg); if (IS_ENABLED(CONFIG_MITIGATION_RETPOLINE) || IS_ENABLED(CONFIG_MITIGATION_SLS)) EMIT1(0xCC); /* int3 */ } @@ -797,7 +811,7 @@ static void emit_bpf_tail_call_indirect(struct bpf_prog *bpf_prog, * rdi == ctx (1st arg) * rcx == prog->bpf_func + X86_TAIL_CALL_OFFSET */ - emit_indirect_jump(&prog, 1 /* rcx */, ip + (prog - start)); + emit_indirect_jump(&prog, BPF_REG_4 /* R4 -> rcx */, ip + (prog - start)); /* out: */ ctx->tail_call_indirect_label = prog - start; @@ -3543,7 +3557,7 @@ static int emit_bpf_dispatcher(u8 **pprog, int a, int b, s64 *progs, u8 *image, if (err) return err; - emit_indirect_jump(&prog, 2 /* rdx */, image + (prog - buf)); + emit_indirect_jump(&prog, BPF_REG_3 /* R3 -> rdx */, image + (prog - buf)); *pprog = prog; return 0; -- 2.34.1 Add support for a new instruction BPF_JMP|BPF_X|BPF_JA, SRC=0, DST=Rx, off=0, imm=0 which does an indirect jump to a location stored in Rx. The register Rx should have type PTR_TO_INSN. This new type assures that the Rx register contains a value (or a range of values) loaded from a correct jump table – map of type instruction array. For example, for a C switch LLVM will generate the following code: 0: r3 = r1 # "switch (r3)" 1: if r3 > 0x13 goto +0x666 # check r3 boundaries 2: r3 <<= 0x3 # adjust to an index in array of addresses 3: r1 = 0xbeef ll # r1 is PTR_TO_MAP_VALUE, r1->map_ptr=M 5: r1 += r3 # r1 inherits boundaries from r3 6: r1 = *(u64 *)(r1 + 0x0) # r1 now has type INSN_TO_PTR 7: gotox r1 # jit will generate proper code Here the gotox instruction corresponds to one particular map. This is possible however to have a gotox instruction which can be loaded from different maps, e.g. 0: r1 &= 0x1 1: r2 <<= 0x3 2: r3 = 0x0 ll # load from map M_1 4: r3 += r2 5: if r1 == 0x0 goto +0x4 6: r1 <<= 0x3 7: r3 = 0x0 ll # load from map M_2 9: r3 += r1 A: r1 = *(u64 *)(r3 + 0x0) B: gotox r1 # jump to target loaded from M_1 or M_2 During check_cfg stage the verifier will collect all the maps which point to inside the subprog being verified. When building the config, the high 16 bytes of the insn_state are used, so this patch (theoretically) supports jump tables of up to 2^16 slots. During the later stage, in check_indirect_jump, it is checked that the register Rx was loaded from a particular instruction array. Signed-off-by: Anton Protopopov Acked-by: Eduard Zingerman --- arch/x86/net/bpf_jit_comp.c | 3 + include/linux/bpf.h | 1 + include/linux/bpf_verifier.h | 9 + kernel/bpf/bpf_insn_array.c | 15 ++ kernel/bpf/core.c | 1 + kernel/bpf/liveness.c | 3 + kernel/bpf/log.c | 1 + kernel/bpf/verifier.c | 364 ++++++++++++++++++++++++++++++++++- 8 files changed, 391 insertions(+), 6 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index c1f686df6fbc..a97a1d778a4c 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2628,6 +2628,9 @@ st: if (is_imm8(insn->off)) break; + case BPF_JMP | BPF_JA | BPF_X: + emit_indirect_jump(&prog, insn->dst_reg, image + addrs[i - 1]); + break; case BPF_JMP | BPF_JA: case BPF_JMP32 | BPF_JA: if (BPF_CLASS(insn->code) == BPF_JMP) { diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 9d41a6affcef..09d5dc541d1c 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1001,6 +1001,7 @@ enum bpf_reg_type { PTR_TO_ARENA, PTR_TO_BUF, /* reg points to a read/write buffer */ PTR_TO_FUNC, /* reg points to a bpf program function */ + PTR_TO_INSN, /* reg points to a bpf program instruction */ CONST_PTR_TO_DYNPTR, /* reg points to a const struct bpf_dynptr */ __BPF_REG_TYPE_MAX, diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 6b820d8d77af..5441341f1ab9 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -527,6 +527,7 @@ struct bpf_insn_aux_data { struct { u32 map_index; /* index into used_maps[] */ u32 map_off; /* offset from value base address */ + struct bpf_iarray *jt; /* jump table for gotox instruction */ }; struct { enum bpf_reg_type reg_type; /* type of pseudo_btf_id */ @@ -840,6 +841,7 @@ struct bpf_verifier_env { struct bpf_scc_info **scc_info; u32 scc_cnt; struct bpf_iarray *succ; + struct bpf_iarray *gotox_tmp_buf; }; static inline struct bpf_func_info_aux *subprog_aux(struct bpf_verifier_env *env, int subprog) @@ -1050,6 +1052,13 @@ static inline bool bpf_stack_narrow_access_ok(int off, int fill_size, int spill_ return !(off % BPF_REG_SIZE); } +static inline bool insn_is_gotox(struct bpf_insn *insn) +{ + return BPF_CLASS(insn->code) == BPF_JMP && + BPF_OP(insn->code) == BPF_JA && + BPF_SRC(insn->code) == BPF_X; +} + const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type); const char *dynptr_type_str(enum bpf_dynptr_type type); const char *iter_type_str(const struct btf *btf, u32 btf_id); diff --git a/kernel/bpf/bpf_insn_array.c b/kernel/bpf/bpf_insn_array.c index dc66154466b3..81b0484e4a2a 100644 --- a/kernel/bpf/bpf_insn_array.c +++ b/kernel/bpf/bpf_insn_array.c @@ -119,6 +119,20 @@ static u64 insn_array_mem_usage(const struct bpf_map *map) return insn_array_alloc_size(map->max_entries); } +static int insn_array_map_direct_value_addr(const struct bpf_map *map, u64 *imm, u32 off) +{ + struct bpf_insn_array *insn_array = cast_insn_array(map); + + if ((off % sizeof(long)) != 0 || + (off / sizeof(long)) >= map->max_entries) + return -EINVAL; + + /* from BPF's point of view, this map is a jump table */ + *imm = (unsigned long)insn_array->ips + off; + + return 0; +} + BTF_ID_LIST_SINGLE(insn_array_btf_ids, struct, bpf_insn_array) const struct bpf_map_ops insn_array_map_ops = { @@ -131,6 +145,7 @@ const struct bpf_map_ops insn_array_map_ops = { .map_delete_elem = insn_array_delete_elem, .map_check_btf = insn_array_check_btf, .map_mem_usage = insn_array_mem_usage, + .map_direct_value_addr = insn_array_map_direct_value_addr, .map_btf_id = &insn_array_btf_ids[0], }; diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 4b62a03d6df5..ef4448f18aad 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1708,6 +1708,7 @@ bool bpf_opcode_in_insntable(u8 code) [BPF_LD | BPF_IND | BPF_B] = true, [BPF_LD | BPF_IND | BPF_H] = true, [BPF_LD | BPF_IND | BPF_W] = true, + [BPF_JMP | BPF_JA | BPF_X] = true, [BPF_JMP | BPF_JCOND] = true, }; #undef BPF_INSN_3_TBL diff --git a/kernel/bpf/liveness.c b/kernel/bpf/liveness.c index bffb495bc933..a7240013fd9d 100644 --- a/kernel/bpf/liveness.c +++ b/kernel/bpf/liveness.c @@ -485,6 +485,9 @@ bpf_insn_successors(struct bpf_verifier_env *env, u32 idx) struct bpf_iarray *succ; int insn_sz; + if (unlikely(insn_is_gotox(insn))) + return env->insn_aux_data[idx].jt; + /* pre-allocated array of size up to 2; reset cnt, as it may have been used already */ succ = env->succ; succ->cnt = 0; diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c index 70221aafc35c..a0c3b35de2ce 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -461,6 +461,7 @@ const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type) [PTR_TO_ARENA] = "arena", [PTR_TO_BUF] = "buf", [PTR_TO_FUNC] = "func", + [PTR_TO_INSN] = "insn", [PTR_TO_MAP_KEY] = "map_key", [CONST_PTR_TO_DYNPTR] = "dynptr_ptr", }; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 2b771e2bf35a..3fdabae07f85 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6006,6 +6006,18 @@ static int check_map_kptr_access(struct bpf_verifier_env *env, u32 regno, return 0; } +/* + * Return the size of the memory region accessible from a pointer to map value. + * For INSN_ARRAY maps whole bpf_insn_array->ips array is accessible. + */ +static u32 map_mem_size(const struct bpf_map *map) +{ + if (map->map_type == BPF_MAP_TYPE_INSN_ARRAY) + return map->max_entries * sizeof(long); + + return map->value_size; +} + /* check read/write into a map element with possible variable offset */ static int check_map_access(struct bpf_verifier_env *env, u32 regno, int off, int size, bool zero_size_allowed, @@ -6015,11 +6027,11 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno, struct bpf_func_state *state = vstate->frame[vstate->curframe]; struct bpf_reg_state *reg = &state->regs[regno]; struct bpf_map *map = reg->map_ptr; + u32 mem_size = map_mem_size(map); struct btf_record *rec; int err, i; - err = check_mem_region_access(env, regno, off, size, map->value_size, - zero_size_allowed); + err = check_mem_region_access(env, regno, off, size, mem_size, zero_size_allowed); if (err) return err; @@ -7481,6 +7493,8 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn { struct bpf_reg_state *regs = cur_regs(env); struct bpf_reg_state *reg = regs + regno; + bool insn_array = reg->type == PTR_TO_MAP_VALUE && + reg->map_ptr->map_type == BPF_MAP_TYPE_INSN_ARRAY; int size, err = 0; size = bpf_size_to_bytes(bpf_size); @@ -7488,7 +7502,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn return size; /* alignment checks will add in reg->off themselves */ - err = check_ptr_alignment(env, reg, off, size, strict_alignment_once); + err = check_ptr_alignment(env, reg, off, size, strict_alignment_once || insn_array); if (err) return err; @@ -7515,6 +7529,11 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn verbose(env, "R%d leaks addr into map\n", value_regno); return -EACCES; } + if (t == BPF_WRITE && insn_array) { + verbose(env, "writes into insn_array not allowed\n"); + return -EACCES; + } + err = check_map_access_type(env, regno, off, size, t); if (err) return err; @@ -7543,6 +7562,14 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn regs[value_regno].type = SCALAR_VALUE; __mark_reg_known(®s[value_regno], val); + } else if (map->map_type == BPF_MAP_TYPE_INSN_ARRAY) { + if (bpf_size != BPF_DW) { + verbose(env, "Invalid read of %d bytes from insn_array\n", + size); + return -EACCES; + } + copy_register_state(®s[value_regno], reg); + regs[value_regno].type = PTR_TO_INSN; } else { mark_reg_unknown(env, regs, value_regno); } @@ -17065,7 +17092,8 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) } dst_reg->type = PTR_TO_MAP_VALUE; dst_reg->off = aux->map_off; - WARN_ON_ONCE(map->max_entries != 1); + WARN_ON_ONCE(map->map_type != BPF_MAP_TYPE_INSN_ARRAY && + map->max_entries != 1); /* We want reg->id to be same (0) as map_value is not distinct */ } else if (insn->src_reg == BPF_PSEUDO_MAP_FD || insn->src_reg == BPF_PSEUDO_MAP_IDX) { @@ -17833,6 +17861,197 @@ static struct bpf_iarray *iarray_realloc(struct bpf_iarray *old, size_t n_elem) return new; } +static int copy_insn_array(struct bpf_map *map, u32 start, u32 end, u32 *items) +{ + struct bpf_insn_array_value *value; + u32 i; + + for (i = start; i <= end; i++) { + value = map->ops->map_lookup_elem(map, &i); + if (!value) + return -EINVAL; + items[i - start] = value->xlated_off; + } + return 0; +} + +static int cmp_ptr_to_u32(const void *a, const void *b) +{ + return *(u32 *)a - *(u32 *)b; +} + +static int sort_insn_array_uniq(u32 *items, int cnt) +{ + int unique = 1; + int i; + + sort(items, cnt, sizeof(items[0]), cmp_ptr_to_u32, NULL); + + for (i = 1; i < cnt; i++) + if (items[i] != items[unique - 1]) + items[unique++] = items[i]; + + return unique; +} + +/* + * sort_unique({map[start], ..., map[end]}) into off + */ +static int copy_insn_array_uniq(struct bpf_map *map, u32 start, u32 end, u32 *off) +{ + u32 n = end - start + 1; + int err; + + err = copy_insn_array(map, start, end, off); + if (err) + return err; + + return sort_insn_array_uniq(off, n); +} + +/* + * Copy all unique offsets from the map + */ +static struct bpf_iarray *jt_from_map(struct bpf_map *map) +{ + struct bpf_iarray *jt; + int n; + + jt = iarray_realloc(NULL, map->max_entries); + if (!jt) + return ERR_PTR(-ENOMEM); + + n = copy_insn_array_uniq(map, 0, map->max_entries - 1, jt->items); + if (n < 0) { + kvfree(jt); + return ERR_PTR(n); + } + + return jt; +} + +/* + * Find and collect all maps which fit in the subprog. Return the result as one + * combined jump table in jt->items (allocated with kvcalloc) + */ +static struct bpf_iarray *jt_from_subprog(struct bpf_verifier_env *env, + int subprog_start, int subprog_end) +{ + struct bpf_iarray *jt = NULL; + struct bpf_map *map; + struct bpf_iarray *jt_cur; + int i; + + for (i = 0; i < env->insn_array_map_cnt; i++) { + /* + * TODO (when needed): collect only jump tables, not static keys + * or maps for indirect calls + */ + map = env->insn_array_maps[i]; + + jt_cur = jt_from_map(map); + if (IS_ERR(jt_cur)) { + kvfree(jt); + return jt_cur; + } + + /* + * This is enough to check one element. The full table is + * checked to fit inside the subprog later in create_jt() + */ + if (jt_cur->items[0] >= subprog_start && jt_cur->items[0] < subprog_end) { + u32 old_cnt = jt ? jt->cnt : 0; + jt = iarray_realloc(jt, old_cnt + jt_cur->cnt); + if (!jt) { + kvfree(jt_cur); + return ERR_PTR(-ENOMEM); + } + memcpy(jt->items + old_cnt, jt_cur->items, jt_cur->cnt << 2); + } + + kvfree(jt_cur); + } + + if (!jt) { + verbose(env, "no jump tables found for subprog starting at %u\n", subprog_start); + return ERR_PTR(-EINVAL); + } + + jt->cnt = sort_insn_array_uniq(jt->items, jt->cnt); + return jt; +} + +static struct bpf_iarray * +create_jt(int t, struct bpf_verifier_env *env) +{ + static struct bpf_subprog_info *subprog; + int subprog_start, subprog_end; + struct bpf_iarray *jt; + int i; + + subprog = bpf_find_containing_subprog(env, t); + subprog_start = subprog->start; + subprog_end = (subprog + 1)->start; + jt = jt_from_subprog(env, subprog_start, subprog_end); + if (IS_ERR(jt)) + return jt; + + /* Check that the every element of the jump table fits within the given subprogram */ + for (i = 0; i < jt->cnt; i++) { + if (jt->items[i] < subprog_start || jt->items[i] >= subprog_end) { + verbose(env, "jump table for insn %d points outside of the subprog [%u,%u]\n", + t, subprog_start, subprog_end); + kvfree(jt); + return ERR_PTR(-EINVAL); + } + } + + return jt; +} + +/* "conditional jump with N edges" */ +static int visit_gotox_insn(int t, struct bpf_verifier_env *env) +{ + int *insn_stack = env->cfg.insn_stack; + int *insn_state = env->cfg.insn_state; + bool keep_exploring = false; + struct bpf_iarray *jt; + int i, w; + + jt = env->insn_aux_data[t].jt; + if (!jt) { + jt = create_jt(t, env); + if (IS_ERR(jt)) + return PTR_ERR(jt); + + env->insn_aux_data[t].jt = jt; + } + + mark_prune_point(env, t); + for (i = 0; i < jt->cnt; i++) { + w = jt->items[i]; + if (w < 0 || w >= env->prog->len) { + verbose(env, "indirect jump out of range from insn %d to %d\n", t, w); + return -EINVAL; + } + + mark_jmp_point(env, w); + + /* EXPLORED || DISCOVERED */ + if (insn_state[w]) + continue; + + if (env->cfg.cur_stack >= env->prog->len) + return -E2BIG; + + insn_stack[env->cfg.cur_stack++] = w; + insn_state[w] |= DISCOVERED; + keep_exploring = true; + } + + return keep_exploring ? KEEP_EXPLORING : DONE_EXPLORING; +} + /* Visits the instruction at index t and returns one of the following: * < 0 - an error occurred * DONE_EXPLORING - the instruction was fully explored @@ -17925,8 +18144,8 @@ static int visit_insn(int t, struct bpf_verifier_env *env) return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL); case BPF_JA: - if (BPF_SRC(insn->code) != BPF_K) - return -EINVAL; + if (BPF_SRC(insn->code) == BPF_X) + return visit_gotox_insn(t, env); if (BPF_CLASS(insn->code) == BPF_JMP) off = insn->off; @@ -18855,6 +19074,9 @@ static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold, return regs_exact(rold, rcur, idmap) && rold->frameno == rcur->frameno; case PTR_TO_ARENA: return true; + case PTR_TO_INSN: + return (rold->off == rcur->off && range_within(rold, rcur) && + tnum_in(rold->var_off, rcur->var_off)); default: return regs_exact(rold, rcur, idmap); } @@ -19864,6 +20086,99 @@ static int process_bpf_exit_full(struct bpf_verifier_env *env, return PROCESS_BPF_EXIT; } +static int indirect_jump_min_max_index(struct bpf_verifier_env *env, + int regno, + struct bpf_map *map, + u32 *pmin_index, u32 *pmax_index) +{ + struct bpf_reg_state *reg = reg_state(env, regno); + u64 min_index, max_index; + const u32 size = 8; + + if (check_add_overflow(reg->umin_value, reg->off, &min_index) || + (min_index > (u64) U32_MAX * size)) { + verbose(env, "the sum of R%u umin_value %llu and off %u is too big\n", + regno, reg->umin_value, reg->off); + return -ERANGE; + } + if (check_add_overflow(reg->umax_value, reg->off, &max_index) || + (max_index > (u64) U32_MAX * size)) { + verbose(env, "the sum of R%u umax_value %llu and off %u is too big\n", + regno, reg->umax_value, reg->off); + return -ERANGE; + } + + min_index /= size; + max_index /= size; + + if (max_index >= map->max_entries) { + verbose(env, "R%u points to outside of jump table: [%llu,%llu] max_entries %u\n", + regno, min_index, max_index, map->max_entries); + return -EINVAL; + } + + *pmin_index = min_index; + *pmax_index = max_index; + return 0; +} + +/* gotox *dst_reg */ +static int check_indirect_jump(struct bpf_verifier_env *env, struct bpf_insn *insn) +{ + struct bpf_verifier_state *other_branch; + struct bpf_reg_state *dst_reg; + struct bpf_map *map; + u32 min_index, max_index; + int err = 0; + int n; + int i; + + dst_reg = reg_state(env, insn->dst_reg); + if (dst_reg->type != PTR_TO_INSN) { + verbose(env, "R%d has type %s, expected PTR_TO_INSN\n", + insn->dst_reg, reg_type_str(env, dst_reg->type)); + return -EINVAL; + } + + map = dst_reg->map_ptr; + if (verifier_bug_if(!map, env, "R%d has an empty map pointer", insn->dst_reg)) + return -EFAULT; + + if (verifier_bug_if(map->map_type != BPF_MAP_TYPE_INSN_ARRAY, env, + "R%d has incorrect map type %d", insn->dst_reg, map->map_type)) + return -EFAULT; + + err = indirect_jump_min_max_index(env, insn->dst_reg, map, &min_index, &max_index); + if (err) + return err; + + /* Ensure that the buffer is large enough */ + if (!env->gotox_tmp_buf || env->gotox_tmp_buf->cnt < max_index - min_index + 1) { + env->gotox_tmp_buf = iarray_realloc(env->gotox_tmp_buf, + max_index - min_index + 1); + if (!env->gotox_tmp_buf) + return -ENOMEM; + } + + n = copy_insn_array_uniq(map, min_index, max_index, env->gotox_tmp_buf->items); + if (n < 0) + return n; + if (n == 0) { + verbose(env, "register R%d doesn't point to any offset in map id=%d\n", + insn->dst_reg, map->id); + return -EINVAL; + } + + for (i = 0; i < n - 1; i++) { + other_branch = push_stack(env, env->gotox_tmp_buf->items[i], + env->insn_idx, env->cur_state->speculative); + if (IS_ERR(other_branch)) + return PTR_ERR(other_branch); + } + env->insn_idx = env->gotox_tmp_buf->items[n-1]; + return 0; +} + static int do_check_insn(struct bpf_verifier_env *env, bool *do_print_state) { int err; @@ -19966,6 +20281,15 @@ static int do_check_insn(struct bpf_verifier_env *env, bool *do_print_state) mark_reg_scratched(env, BPF_REG_0); } else if (opcode == BPF_JA) { + if (BPF_SRC(insn->code) == BPF_X) { + if (insn->src_reg != BPF_REG_0 || + insn->imm != 0 || insn->off != 0) { + verbose(env, "BPF_JA|BPF_X uses reserved fields\n"); + return -EINVAL; + } + return check_indirect_jump(env, insn); + } + if (BPF_SRC(insn->code) != BPF_K || insn->src_reg != BPF_REG_0 || insn->dst_reg != BPF_REG_0 || @@ -20482,6 +20806,7 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, case BPF_MAP_TYPE_QUEUE: case BPF_MAP_TYPE_STACK: case BPF_MAP_TYPE_ARENA: + case BPF_MAP_TYPE_INSN_ARRAY: break; default: verbose(env, @@ -21039,6 +21364,27 @@ static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off, return 0; } +/* + * Clean up dynamically allocated fields of aux data for instructions [start, ...] + */ +static void clear_insn_aux_data(struct bpf_verifier_env *env, int start, int len) +{ + struct bpf_insn_aux_data *aux_data = env->insn_aux_data; + struct bpf_insn *insns = env->prog->insnsi; + int end = start + len; + int i; + + for (i = start; i < end; i++) { + if (insn_is_gotox(&insns[i])) { + kvfree(aux_data[i].jt); + aux_data[i].jt = NULL; + } + + if (bpf_is_ldimm64(&insns[i])) + i++; + } +} + static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt) { struct bpf_insn_aux_data *aux_data = env->insn_aux_data; @@ -21062,6 +21408,8 @@ static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt) adjust_insn_arrays_after_remove(env, off, cnt); + clear_insn_aux_data(env, off, cnt); + memmove(aux_data + off, aux_data + off + cnt, sizeof(*aux_data) * (orig_prog_len - off - cnt)); @@ -21706,6 +22054,8 @@ static int jit_subprogs(struct bpf_verifier_env *env) func[i]->aux->jited_linfo = prog->aux->jited_linfo; func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx; func[i]->aux->arena = prog->aux->arena; + func[i]->aux->used_maps = env->used_maps; + func[i]->aux->used_map_cnt = env->used_map_cnt; num_exentries = 0; insn = func[i]->insnsi; for (j = 0; j < func[i]->len; j++, insn++) { @@ -24912,12 +25262,14 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 err_unlock: if (!is_priv) mutex_unlock(&bpf_verifier_lock); + clear_insn_aux_data(env, 0, env->prog->len); vfree(env->insn_aux_data); err_free_env: bpf_stack_liveness_free(env); kvfree(env->cfg.insn_postorder); kvfree(env->scc_info); kvfree(env->succ); + kvfree(env->gotox_tmp_buf); kvfree(env); return ret; } -- 2.34.1 Add support for indirect jump instruction. Example output from bpftool: 0: (79) r3 = *(u64 *)(r1 +0) 1: (25) if r3 > 0x4 goto pc+666 2: (67) r3 <<= 3 3: (18) r1 = 0xffffbeefspameggs 5: (0f) r1 += r3 6: (79) r1 = *(u64 *)(r1 +0) 7: (0d) gotox r1 Signed-off-by: Anton Protopopov Acked-by: Eduard Zingerman --- kernel/bpf/disasm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c index 20883c6b1546..f8a3c7eb451e 100644 --- a/kernel/bpf/disasm.c +++ b/kernel/bpf/disasm.c @@ -358,6 +358,9 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs, } else if (insn->code == (BPF_JMP | BPF_JA)) { verbose(cbs->private_data, "(%02x) goto pc%+d\n", insn->code, insn->off); + } else if (insn->code == (BPF_JMP | BPF_JA | BPF_X)) { + verbose(cbs->private_data, "(%02x) gotox r%d\n", + insn->code, insn->dst_reg); } else if (insn->code == (BPF_JMP | BPF_JCOND) && insn->src_reg == BPF_MAY_GOTO) { verbose(cbs->private_data, "(%02x) may_goto pc%+d\n", -- 2.34.1 For v4 instruction set LLVM is allowed to generate indirect jumps for switch statements and for 'goto *rX' assembly. Every such a jump will be accompanied by necessary metadata, e.g. (`llvm-objdump -Sr ...`): 0: r2 = 0x0 ll 0000000000000030: R_BPF_64_64 BPF.JT.0.0 Here BPF.JT.1.0 is a symbol residing in the .jumptables section: Symbol table: 4: 0000000000000000 240 OBJECT GLOBAL DEFAULT 4 BPF.JT.0.0 The -bpf-min-jump-table-entries llvm option may be used to control the minimal size of a switch which will be converted to an indirect jumps. Signed-off-by: Anton Protopopov Acked-by: Eduard Zingerman --- tools/lib/bpf/libbpf.c | 249 +++++++++++++++++++++++++++++++- tools/lib/bpf/libbpf_internal.h | 4 + tools/lib/bpf/libbpf_probes.c | 4 + tools/lib/bpf/linker.c | 9 +- 4 files changed, 263 insertions(+), 3 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b90574f39d1c..49a1411bfaf7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -190,6 +190,7 @@ static const char * const map_type_name[] = { [BPF_MAP_TYPE_USER_RINGBUF] = "user_ringbuf", [BPF_MAP_TYPE_CGRP_STORAGE] = "cgrp_storage", [BPF_MAP_TYPE_ARENA] = "arena", + [BPF_MAP_TYPE_INSN_ARRAY] = "insn_array", }; static const char * const prog_type_name[] = { @@ -369,6 +370,7 @@ enum reloc_type { RELO_EXTERN_CALL, RELO_SUBPROG_ADDR, RELO_CORE, + RELO_INSN_ARRAY, }; struct reloc_desc { @@ -379,7 +381,16 @@ struct reloc_desc { struct { int map_idx; int sym_off; - int ext_idx; + /* + * The following two fields can be unionized, as the + * ext_idx field is used for extern symbols, and the + * sym_size is used for jump tables, which are never + * extern + */ + union { + int ext_idx; + int sym_size; + }; }; }; }; @@ -421,6 +432,11 @@ struct bpf_sec_def { libbpf_prog_attach_fn_t prog_attach_fn; }; +struct bpf_light_subprog { + __u32 sec_insn_off; + __u32 sub_insn_off; +}; + /* * bpf_prog should be a better name but it has been used in * linux/filter.h. @@ -494,6 +510,9 @@ struct bpf_program { __u32 line_info_cnt; __u32 prog_flags; __u8 hash[SHA256_DIGEST_LENGTH]; + + struct bpf_light_subprog *subprogs; + __u32 subprog_cnt; }; struct bpf_struct_ops { @@ -667,6 +686,7 @@ struct elf_state { int symbols_shndx; bool has_st_ops; int arena_data_shndx; + int jumptables_data_shndx; }; struct usdt_manager; @@ -738,6 +758,16 @@ struct bpf_object { void *arena_data; size_t arena_data_sz; + void *jumptables_data; + size_t jumptables_data_sz; + + struct { + struct bpf_program *prog; + int sym_off; + int fd; + } *jumptable_maps; + size_t jumptable_map_cnt; + struct kern_feature_cache *feat_cache; char *token_path; int token_fd; @@ -764,6 +794,7 @@ void bpf_program__unload(struct bpf_program *prog) zfree(&prog->func_info); zfree(&prog->line_info); + zfree(&prog->subprogs); } static void bpf_program__exit(struct bpf_program *prog) @@ -3942,6 +3973,13 @@ static int bpf_object__elf_collect(struct bpf_object *obj) } else if (strcmp(name, ARENA_SEC) == 0) { obj->efile.arena_data = data; obj->efile.arena_data_shndx = idx; + } else if (strcmp(name, JUMPTABLES_SEC) == 0) { + obj->jumptables_data = malloc(data->d_size); + if (!obj->jumptables_data) + return -ENOMEM; + memcpy(obj->jumptables_data, data->d_buf, data->d_size); + obj->jumptables_data_sz = data->d_size; + obj->efile.jumptables_data_shndx = idx; } else { pr_info("elf: skipping unrecognized data section(%d) %s\n", idx, name); @@ -4634,6 +4672,16 @@ static int bpf_program__record_reloc(struct bpf_program *prog, return 0; } + /* jump table data relocation */ + if (shdr_idx == obj->efile.jumptables_data_shndx) { + reloc_desc->type = RELO_INSN_ARRAY; + reloc_desc->insn_idx = insn_idx; + reloc_desc->map_idx = -1; + reloc_desc->sym_off = sym->st_value; + reloc_desc->sym_size = sym->st_size; + return 0; + } + /* generic map reference relocation */ if (type == LIBBPF_MAP_UNSPEC) { if (!bpf_object__shndx_is_maps(obj, shdr_idx)) { @@ -6144,6 +6192,157 @@ static void poison_kfunc_call(struct bpf_program *prog, int relo_idx, insn->imm = POISON_CALL_KFUNC_BASE + ext_idx; } +static int find_jt_map(struct bpf_object *obj, struct bpf_program *prog, int sym_off) +{ + size_t i; + + for (i = 0; i < obj->jumptable_map_cnt; i++) { + /* + * This might happen that same offset is used for two different + * programs (as jump tables can be the same). However, for + * different programs different maps should be created. + */ + if (obj->jumptable_maps[i].sym_off == sym_off && + obj->jumptable_maps[i].prog == prog) + return obj->jumptable_maps[i].fd; + } + + return -ENOENT; +} + +static int add_jt_map(struct bpf_object *obj, struct bpf_program *prog, int sym_off, int map_fd) +{ + size_t new_cnt = obj->jumptable_map_cnt + 1; + size_t size = sizeof(obj->jumptable_maps[0]); + void *tmp; + + tmp = libbpf_reallocarray(obj->jumptable_maps, new_cnt, size); + if (!tmp) + return -ENOMEM; + + obj->jumptable_maps = tmp; + obj->jumptable_maps[new_cnt - 1].prog = prog; + obj->jumptable_maps[new_cnt - 1].sym_off = sym_off; + obj->jumptable_maps[new_cnt - 1].fd = map_fd; + obj->jumptable_map_cnt = new_cnt; + + return 0; +} + +static int find_subprog_idx(struct bpf_program *prog, int insn_idx) +{ + int i; + + for (i = prog->subprog_cnt - 1; i >= 0; i--) { + if (insn_idx >= prog->subprogs[i].sub_insn_off) + return i; + } + + return -1; +} + +static int create_jt_map(struct bpf_object *obj, struct bpf_program *prog, struct reloc_desc *relo) +{ + const __u32 jt_entry_size = 8; + int sym_off = relo->sym_off; + int jt_size = relo->sym_size; + __u32 max_entries = jt_size / jt_entry_size; + __u32 value_size = sizeof(struct bpf_insn_array_value); + struct bpf_insn_array_value val = {}; + int subprog_idx; + int map_fd, err; + __u64 insn_off; + __u64 *jt; + __u32 i; + + map_fd = find_jt_map(obj, prog, sym_off); + if (map_fd >= 0) + return map_fd; + + if (sym_off % jt_entry_size) { + pr_warn("jumptable start %d should be multiple of %u\n", + sym_off, jt_entry_size); + return -EINVAL; + } + + if (jt_size % jt_entry_size) { + pr_warn("jumptable size %d should be multiple of %u\n", + jt_size, jt_entry_size); + return -EINVAL; + } + + map_fd = bpf_map_create(BPF_MAP_TYPE_INSN_ARRAY, ".jumptables", + 4, value_size, max_entries, NULL); + if (map_fd < 0) + return map_fd; + + if (!obj->jumptables_data) { + pr_warn("map '.jumptables': ELF file is missing jump table data\n"); + err = -EINVAL; + goto err_close; + } + if (sym_off + jt_size > obj->jumptables_data_sz) { + pr_warn("jumptables_data size is %zd, trying to access %d\n", + obj->jumptables_data_sz, sym_off + jt_size); + err = -EINVAL; + goto err_close; + } + + subprog_idx = -1; /* main program */ + if (relo->insn_idx < 0 || relo->insn_idx >= prog->insns_cnt) { + pr_warn("invalid instruction index %d\n", relo->insn_idx); + err = -EINVAL; + goto err_close; + } + if (prog->subprogs) + subprog_idx = find_subprog_idx(prog, relo->insn_idx); + + jt = (__u64 *)(obj->jumptables_data + sym_off); + for (i = 0; i < max_entries; i++) { + /* + * The offset should be made to be relative to the beginning of + * the main function, not the subfunction. + */ + insn_off = jt[i]/sizeof(struct bpf_insn); + if (subprog_idx >= 0) { + insn_off -= prog->subprogs[subprog_idx].sec_insn_off; + insn_off += prog->subprogs[subprog_idx].sub_insn_off; + } else { + insn_off -= prog->sec_insn_off; + } + + /* + * LLVM-generated jump tables contain u64 records, however + * should contain values that fit in u32. + */ + if (insn_off > UINT32_MAX) { + pr_warn("invalid jump table value 0x%llx at offset %d\n", + jt[i], sym_off + i); + err = -EINVAL; + goto err_close; + } + + val.orig_off = insn_off; + err = bpf_map_update_elem(map_fd, &i, &val, 0); + if (err) + goto err_close; + } + + err = bpf_map_freeze(map_fd); + if (err) + goto err_close; + + err = add_jt_map(obj, prog, sym_off, map_fd); + if (err) + goto err_close; + + return map_fd; + +err_close: + close(map_fd); + return err; +} + /* Relocate data references within program code: * - map references; * - global variable references; @@ -6235,6 +6434,20 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) case RELO_CORE: /* will be handled by bpf_program_record_relos() */ break; + case RELO_INSN_ARRAY: { + int map_fd; + + map_fd = create_jt_map(obj, prog, relo); + if (map_fd < 0) { + pr_warn("prog '%s': relo #%d: can't create jump table: sym_off %u\n", + prog->name, i, relo->sym_off); + return map_fd; + } + insn[0].src_reg = BPF_PSEUDO_MAP_VALUE; + insn->imm = map_fd; + insn->off = 0; + } + break; default: pr_warn("prog '%s': relo #%d: bad relo type %d\n", prog->name, i, relo->type); @@ -6432,6 +6645,24 @@ static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_progra return 0; } +static int save_subprog_offsets(struct bpf_program *main_prog, struct bpf_program *subprog) +{ + size_t size = sizeof(main_prog->subprogs[0]); + int new_cnt = main_prog->subprog_cnt + 1; + void *tmp; + + tmp = libbpf_reallocarray(main_prog->subprogs, new_cnt, size); + if (!tmp) + return -ENOMEM; + + main_prog->subprogs = tmp; + main_prog->subprogs[new_cnt - 1].sec_insn_off = subprog->sec_insn_off; + main_prog->subprogs[new_cnt - 1].sub_insn_off = subprog->sub_insn_off; + main_prog->subprog_cnt = new_cnt; + + return 0; +} + static int bpf_object__append_subprog_code(struct bpf_object *obj, struct bpf_program *main_prog, struct bpf_program *subprog) @@ -6461,6 +6692,15 @@ bpf_object__append_subprog_code(struct bpf_object *obj, struct bpf_program *main err = append_subprog_relos(main_prog, subprog); if (err) return err; + + /* Save subprogram offsets */ + err = save_subprog_offsets(main_prog, subprog); + if (err) { + pr_warn("prog '%s': failed to add subprog offsets: %s\n", + main_prog->name, errstr(err)); + return err; + } + return 0; } @@ -9228,6 +9468,13 @@ void bpf_object__close(struct bpf_object *obj) zfree(&obj->arena_data); + zfree(&obj->jumptables_data); + obj->jumptables_data_sz = 0; + + for (i = 0; i < obj->jumptable_map_cnt; i++) + close(obj->jumptable_maps[i].fd); + zfree(&obj->jumptable_maps); + free(obj); } diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 35b2527bedec..93bc39bd1307 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -74,6 +74,10 @@ #define ELF64_ST_VISIBILITY(o) ((o) & 0x03) #endif +#ifndef JUMPTABLES_SEC +#define JUMPTABLES_SEC ".jumptables" +#endif + #define BTF_INFO_ENC(kind, kind_flag, vlen) \ ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index 9dfbe7750f56..bccf4bb747e1 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -364,6 +364,10 @@ static int probe_map_create(enum bpf_map_type map_type) case BPF_MAP_TYPE_SOCKHASH: case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: break; + case BPF_MAP_TYPE_INSN_ARRAY: + key_size = sizeof(__u32); + value_size = sizeof(struct bpf_insn_array_value); + break; case BPF_MAP_TYPE_UNSPEC: default: return -EOPNOTSUPP; diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 56ae77047bc3..f6ca3b23b17a 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -27,6 +27,7 @@ #include "strset.h" #define BTF_EXTERN_SEC ".extern" +#define JUMPTABLES_REL_SEC ".rel.jumptables" struct src_sec { const char *sec_name; @@ -2025,6 +2026,9 @@ static int linker_append_elf_sym(struct bpf_linker *linker, struct src_obj *obj, obj->sym_map[src_sym_idx] = dst_sec->sec_sym_idx; return 0; } + + if (strcmp(src_sec->sec_name, JUMPTABLES_SEC) == 0) + goto add_sym; } if (sym_bind == STB_LOCAL) @@ -2271,8 +2275,9 @@ static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *ob insn->imm += sec->dst_off / sizeof(struct bpf_insn); else insn->imm += sec->dst_off; - } else { - pr_warn("relocation against STT_SECTION in non-exec section is not supported!\n"); + } else if (strcmp(src_sec->sec_name, JUMPTABLES_REL_SEC) != 0) { + pr_warn("relocation against STT_SECTION in section %s is not supported!\n", + src_sec->sec_name); return -EINVAL; } } -- 2.34.1 Teach bpftool to recognize instruction array map type. Signed-off-by: Anton Protopopov Acked-by: Quentin Monnet --- tools/bpf/bpftool/Documentation/bpftool-map.rst | 3 ++- tools/bpf/bpftool/map.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst index 252e4c538edb..1af3305ea2b2 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-map.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst @@ -55,7 +55,8 @@ MAP COMMANDS | | **devmap** | **devmap_hash** | **sockmap** | **cpumap** | **xskmap** | **sockhash** | | **cgroup_storage** | **reuseport_sockarray** | **percpu_cgroup_storage** | | **queue** | **stack** | **sk_storage** | **struct_ops** | **ringbuf** | **inode_storage** -| | **task_storage** | **bloom_filter** | **user_ringbuf** | **cgrp_storage** | **arena** } +| | **task_storage** | **bloom_filter** | **user_ringbuf** | **cgrp_storage** | **arena** +| | **insn_array** } DESCRIPTION =========== diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index c9de44a45778..7ebf7dbcfba4 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -1477,7 +1477,8 @@ static int do_help(int argc, char **argv) " devmap | devmap_hash | sockmap | cpumap | xskmap | sockhash |\n" " cgroup_storage | reuseport_sockarray | percpu_cgroup_storage |\n" " queue | stack | sk_storage | struct_ops | ringbuf | inode_storage |\n" - " task_storage | bloom_filter | user_ringbuf | cgrp_storage | arena }\n" + " task_storage | bloom_filter | user_ringbuf | cgrp_storage | arena |\n" + " insn_array }\n" " " HELP_SPEC_OPTIONS " |\n" " {-f|--bpffs} | {-n|--nomount} }\n" "", -- 2.34.1 Add a set of tests to validate core gotox functionality without need to rely on compilers. Signed-off-by: Anton Protopopov --- .../selftests/bpf/prog_tests/verifier.c | 2 + .../selftests/bpf/progs/verifier_gotox.c | 353 ++++++++++++++++++ 2 files changed, 355 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/verifier_gotox.c diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index c0e8ffdaa484..4b4b081b46cc 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -35,6 +35,7 @@ #include "verifier_global_subprogs.skel.h" #include "verifier_global_ptr_args.skel.h" #include "verifier_gotol.skel.h" +#include "verifier_gotox.skel.h" #include "verifier_helper_access_var_len.skel.h" #include "verifier_helper_packet_access.skel.h" #include "verifier_helper_restricted.skel.h" @@ -173,6 +174,7 @@ void test_verifier_div_overflow(void) { RUN(verifier_div_overflow); } void test_verifier_global_subprogs(void) { RUN(verifier_global_subprogs); } void test_verifier_global_ptr_args(void) { RUN(verifier_global_ptr_args); } void test_verifier_gotol(void) { RUN(verifier_gotol); } +void test_verifier_gotox(void) { RUN(verifier_gotox); } void test_verifier_helper_access_var_len(void) { RUN(verifier_helper_access_var_len); } void test_verifier_helper_packet_access(void) { RUN(verifier_helper_packet_access); } void test_verifier_helper_restricted(void) { RUN(verifier_helper_restricted); } diff --git a/tools/testing/selftests/bpf/progs/verifier_gotox.c b/tools/testing/selftests/bpf/progs/verifier_gotox.c new file mode 100644 index 000000000000..f7bf0a5e0346 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/verifier_gotox.c @@ -0,0 +1,353 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Isovalent */ + +#include +#include +#include "bpf_misc.h" +#include "../../../include/linux/filter.h" + +#ifdef __TARGET_ARCH_x86 + +#define DEFINE_SIMPLE_JUMP_TABLE_PROG(NAME, SRC_REG, OFF, IMM, OUTCOME) \ + \ + SEC("socket") \ + OUTCOME \ + __naked void jump_table_ ## NAME(void) \ + { \ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ + jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 += 8; \ + r0 = *(u64 *)(r0 + 0); \ + .8byte %[gotox_r0]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ + " : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, (SRC_REG), (OFF) , (IMM))) \ + : __clobber_all); \ + } + +/* + * The first program which doesn't use reserved fields + * loads and works properly. The rest fail to load. + */ +DEFINE_SIMPLE_JUMP_TABLE_PROG(ok, BPF_REG_0, 0, 0, __success __retval(1)) +DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_src_reg, BPF_REG_1, 0, 0, __failure __msg("BPF_JA|BPF_X uses reserved fields")) +DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_non_zero_off, BPF_REG_0, 1, 0, __failure __msg("BPF_JA|BPF_X uses reserved fields")) +DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_non_zero_imm, BPF_REG_0, 0, 1, __failure __msg("BPF_JA|BPF_X uses reserved fields")) + +/* + * Gotox is forbidden when there is no jump table loaded + * which points to the sub-function where the gotox is used + */ +SEC("socket") +__failure __msg("no jump tables found for subprog starting at 0") +__naked void jump_table_no_jump_table(void) +{ + asm volatile (" \ + .8byte %[gotox_r0]; \ + r0 = 1; \ + exit; \ +" : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) + : __clobber_all); +} + +/* + * Incorrect type of the target register, only PTR_TO_INSN allowed + */ +SEC("socket") +__failure __msg("R1 has type scalar, expected PTR_TO_INSN") +__naked void jump_table_incorrect_dst_reg_type(void) +{ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ +jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 += 8; \ + r0 = *(u64 *)(r0 + 0); \ + r1 = 42; \ + .8byte %[gotox_r1]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ +" : \ + : __imm_insn(gotox_r1, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_1, 0, 0 , 0)) + : __clobber_all); +} + +#define DEFINE_INVALID_SIZE_PROG(READ_SIZE, OUTCOME) \ + \ + SEC("socket") \ + OUTCOME \ + __naked void jump_table_invalid_read_size_ ## READ_SIZE(void) \ + { \ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ + jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 += 8; \ + r0 = *(" #READ_SIZE " *)(r0 + 0); \ + .8byte %[gotox_r0]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ + " : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) \ + : __clobber_all); \ + } + +DEFINE_INVALID_SIZE_PROG(u32, __failure __msg("Invalid read of 4 bytes from insn_array")) +DEFINE_INVALID_SIZE_PROG(u16, __failure __msg("Invalid read of 2 bytes from insn_array")) +DEFINE_INVALID_SIZE_PROG(u8, __failure __msg("Invalid read of 1 bytes from insn_array")) + +SEC("socket") +__failure __msg("misaligned value access off 0+1+0 size 8") +__naked void jump_table_misaligned_access(void) +{ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ +jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 += 1; \ + r0 = *(u64 *)(r0 + 0); \ + .8byte %[gotox_r0]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ +" : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) + : __clobber_all); +} + +SEC("socket") +__failure __msg("invalid access to map value, value_size=16 off=24 size=8") +__naked void jump_table_invalid_mem_acceess_pos(void) +{ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ +jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 += 24; \ + r0 = *(u64 *)(r0 + 0); \ + .8byte %[gotox_r0]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ +" : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) + : __clobber_all); +} + +SEC("socket") +__failure __msg("invalid access to map value, value_size=16 off=-24 size=8") +__naked void jump_table_invalid_mem_acceess_neg(void) +{ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ +jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 -= 24; \ + r0 = *(u64 *)(r0 + 0); \ + .8byte %[gotox_r0]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ +" : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) + : __clobber_all); +} + +SEC("socket") +__success __retval(1) +__naked void jump_table_add_sub_ok(void) +{ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ +jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 -= 24; \ + r0 += 32; \ + r0 = *(u64 *)(r0 + 0); \ + .8byte %[gotox_r0]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ +" : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) + : __clobber_all); +} + +SEC("socket") +__failure __msg("writes into insn_array not allowed") +__naked void jump_table_no_writes(void) +{ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ +jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 += 8; \ + r1 = 0xbeef; \ + *(u64 *)(r0 + 0) = r1; \ + .8byte %[gotox_r0]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ +" : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) + : __clobber_all); +} + +#define DEFINE_JUMP_TABLE_USE_REG(REG) \ + SEC("socket") \ + __success __retval(1) \ + __naked void jump_table_use_reg_r ## REG(void) \ + { \ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ + jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .size jt0_%=, 16; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 += 8; \ + r" #REG " = *(u64 *)(r0 + 0); \ + .8byte %[gotox_rX]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + exit; \ + " : \ + : __imm_insn(gotox_rX, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_ ## REG, 0, 0 , 0)) \ + : __clobber_all); \ + } + +DEFINE_JUMP_TABLE_USE_REG(0) +DEFINE_JUMP_TABLE_USE_REG(1) +DEFINE_JUMP_TABLE_USE_REG(2) +DEFINE_JUMP_TABLE_USE_REG(3) +DEFINE_JUMP_TABLE_USE_REG(4) +DEFINE_JUMP_TABLE_USE_REG(5) +DEFINE_JUMP_TABLE_USE_REG(6) +DEFINE_JUMP_TABLE_USE_REG(7) +DEFINE_JUMP_TABLE_USE_REG(8) +DEFINE_JUMP_TABLE_USE_REG(9) + +__used static int test_subprog(void) +{ + return 0; +} + +SEC("socket") +__failure __msg("jump table for insn 4 points outside of the subprog [0,10]") +__naked void jump_table_outside_subprog(void) +{ + asm volatile (" \ + .pushsection .jumptables,\"\",@progbits; \ +jt0_%=: \ + .quad ret0_%=; \ + .quad ret1_%=; \ + .quad ret_out_%=; \ + .size jt0_%=, 24; \ + .global jt0_%=; \ + .popsection; \ + \ + r0 = jt0_%= ll; \ + r0 += 8; \ + *(u64 *)(r0 + 0) = r1; \ + .8byte %[gotox_r0]; \ + ret0_%=: \ + r0 = 0; \ + exit; \ + ret1_%=: \ + r0 = 1; \ + call test_subprog; \ + exit; \ + ret_out_%=: \ +" : \ + : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X, BPF_REG_0, 0, 0 , 0)) + : __clobber_all); +} + +#endif /* __TARGET_ARCH_x86 */ + +char _license[] SEC("license") = "GPL"; -- 2.34.1 Add C-level selftests for indirect jumps to validate LLVM and libbpf functionality. The tests are intentionally disabled, to be run locally by developers, but will not make the CI red. Signed-off-by: Anton Protopopov --- tools/testing/selftests/bpf/Makefile | 4 +- .../selftests/bpf/prog_tests/bpf_gotox.c | 276 ++++++++++++ tools/testing/selftests/bpf/progs/bpf_gotox.c | 401 ++++++++++++++++++ 3 files changed, 680 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_gotox.c create mode 100644 tools/testing/selftests/bpf/progs/bpf_gotox.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 64997fa47053..d418863b2fb5 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -454,7 +454,9 @@ BPF_CFLAGS = -g -Wall -Werror -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN) \ -I$(abspath $(OUTPUT)/../usr/include) \ -std=gnu11 \ -fno-strict-aliasing \ - -Wno-compare-distinct-pointer-types + -Wno-compare-distinct-pointer-types \ + -Wno-initializer-overrides \ + # # TODO: enable me -Wsign-compare CLANG_CFLAGS = $(CLANG_SYS_INCLUDES) diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_gotox.c b/tools/testing/selftests/bpf/prog_tests/bpf_gotox.c new file mode 100644 index 000000000000..bb0ebd16df43 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/bpf_gotox.c @@ -0,0 +1,276 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "bpf_gotox.skel.h" + +#if 0 +static void __test_run(struct bpf_program *prog, void *ctx_in, size_t ctx_size_in) +{ + LIBBPF_OPTS(bpf_test_run_opts, topts, + .ctx_in = ctx_in, + .ctx_size_in = ctx_size_in, + ); + int err, prog_fd; + + prog_fd = bpf_program__fd(prog); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run_opts err"); +} + +static void check_simple(struct bpf_gotox *skel, + struct bpf_program *prog, + __u64 ctx_in, + __u64 expected) +{ + skel->bss->ret_user = 0; + + __test_run(prog, &ctx_in, sizeof(ctx_in)); + + if (!ASSERT_EQ(skel->bss->ret_user, expected, "skel->bss->ret_user")) + return; +} + +static void check_simple_fentry(struct bpf_gotox *skel, + struct bpf_program *prog, + __u64 ctx_in, + __u64 expected) +{ + skel->bss->in_user = ctx_in; + skel->bss->ret_user = 0; + + /* trigger */ + usleep(1); + + if (!ASSERT_EQ(skel->bss->ret_user, expected, "skel->bss->ret_user")) + return; +} + +/* validate that for two loads of the same jump table libbpf generates only one map */ +static void check_one_map_two_jumps(struct bpf_gotox *skel) +{ + struct bpf_prog_info prog_info; + struct bpf_map_info map_info; + __u32 len; + __u32 map_ids[16]; + int prog_fd, map_fd; + int ret; + int i; + bool seen = false; + + memset(&prog_info, 0, sizeof(prog_info)); + prog_info.map_ids = (long)map_ids; + prog_info.nr_map_ids = ARRAY_SIZE(map_ids); + prog_fd = bpf_program__fd(skel->progs.one_map_two_jumps); + if (!ASSERT_GE(prog_fd, 0, "bpf_program__fd(one_map_two_jumps)")) + return; + + len = sizeof(prog_info); + ret = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &len); + if (!ASSERT_OK(ret, "bpf_obj_get_info_by_fd(prog_fd)")) + return; + + for (i = 0; i < prog_info.nr_map_ids; i++) { + map_fd = bpf_map_get_fd_by_id(map_ids[i]); + if (!ASSERT_GE(map_fd, 0, "bpf_program__fd(one_map_two_jumps)")) + return; + + len = sizeof(map_info); + memset(&map_info, 0, len); + ret = bpf_obj_get_info_by_fd(map_fd, &map_info, &len); + if (!ASSERT_OK(ret, "bpf_obj_get_info_by_fd(map_fd)")) { + close(map_fd); + return; + } + + if (map_info.type == BPF_MAP_TYPE_INSN_ARRAY) { + if (!ASSERT_EQ(seen, false, "more than one INSN_ARRAY map")) { + close(map_fd); + return; + } + seen = true; + } + close(map_fd); + } + + ASSERT_EQ(seen, true, "no INSN_ARRAY map"); +} + +static void check_one_switch(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {2, 3, 4, 5, 7, 19, 19}; + int i; + + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.one_switch, in[i], out[i]); +} + +static void check_one_switch_non_zero_sec_off(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {2, 3, 4, 5, 7, 19, 19}; + int i; + + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.one_switch_non_zero_sec_off, in[i], out[i]); +} + +static void check_two_switches(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {103, 104, 107, 205, 115, 1019, 1019}; + int i; + + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.two_switches, in[i], out[i]); +} + +static void check_big_jump_table(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 11, 27, 31, 22, 45, 99}; + __u64 out[] = {2, 3, 4, 5, 19, 19, 19}; + int i; + + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.big_jump_table, in[i], out[i]); +} + +static void check_one_jump_two_maps(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {12, 15, 7 , 15, 12, 15, 15}; + int i; + + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.one_jump_two_maps, in[i], out[i]); +} + +static void check_static_global(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {2, 3, 4, 5, 7, 19, 19}; + int i; + + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.use_static_global1, in[i], out[i]); + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.use_static_global2, in[i], out[i]); +} + +static void check_nonstatic_global(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {2, 3, 4, 5, 7, 19, 19}; + int i; + + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.use_nonstatic_global1, in[i], out[i]); + + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple(skel, skel->progs.use_nonstatic_global2, in[i], out[i]); +} + +static void check_other_sec(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {2, 3, 4, 5, 7, 19, 19}; + int i; + + bpf_program__attach(skel->progs.simple_test_other_sec); + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple_fentry(skel, skel->progs.simple_test_other_sec, in[i], out[i]); +} + +static void check_static_global_other_sec(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {2, 3, 4, 5, 7, 19, 19}; + int i; + + bpf_program__attach(skel->progs.use_static_global_other_sec); + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple_fentry(skel, skel->progs.use_static_global_other_sec, in[i], out[i]); +} + +static void check_nonstatic_global_other_sec(struct bpf_gotox *skel) +{ + __u64 in[] = {0, 1, 2, 3, 4, 5, 77}; + __u64 out[] = {2, 3, 4, 5, 7, 19, 19}; + int i; + + bpf_program__attach(skel->progs.use_nonstatic_global_other_sec); + for (i = 0; i < ARRAY_SIZE(in); i++) + check_simple_fentry(skel, skel->progs.use_nonstatic_global_other_sec, in[i], out[i]); +} + +static void __test_bpf_gotox(void) +{ + struct bpf_gotox *skel; + int ret; + + skel = bpf_gotox__open(); + if (!ASSERT_NEQ(skel, NULL, "bpf_gotox__open")) + return; + + ret = bpf_gotox__load(skel); + if (!ASSERT_OK(ret, "bpf_gotox__load")) + return; + + if (test__start_subtest("one-switch")) + check_one_switch(skel); + + if (test__start_subtest("one-switch-non-zero-sec-offset")) + check_one_switch_non_zero_sec_off(skel); + + if (test__start_subtest("two-switches")) + check_two_switches(skel); + + if (test__start_subtest("big-jump-table")) + check_big_jump_table(skel); + + if (test__start_subtest("static-global")) + check_static_global(skel); + + if (test__start_subtest("nonstatic-global")) + check_nonstatic_global(skel); + + if (test__start_subtest("other-sec")) + check_other_sec(skel); + + if (test__start_subtest("static-global-other-sec")) + check_static_global_other_sec(skel); + + if (test__start_subtest("nonstatic-global-other-sec")) + check_nonstatic_global_other_sec(skel); + + if (test__start_subtest("one-jump-two-maps")) + check_one_jump_two_maps(skel); + + if (test__start_subtest("one-map-two-jumps")) + check_one_map_two_jumps(skel); + + bpf_gotox__destroy(skel); +} +#else +static void __test_bpf_gotox(void) +{ + test__skip(); +} +#endif + +void test_bpf_gotox(void) +{ + __test_bpf_gotox(); +} diff --git a/tools/testing/selftests/bpf/progs/bpf_gotox.c b/tools/testing/selftests/bpf/progs/bpf_gotox.c new file mode 100644 index 000000000000..16ad6cf279c0 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/bpf_gotox.c @@ -0,0 +1,401 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "vmlinux.h" +#include +#include +#include +#include "bpf_misc.h" + +#if 0 +__u64 in_user; +__u64 ret_user; + +struct simple_ctx { + __u64 x; +}; + +__u64 some_var; + +/* + * This function adds code which will be replaced by a different + * number of instructions by the verifier. This adds additional + * stress on testing the insn_array maps corresponding to indirect jumps. + */ +static __always_inline void adjust_insns(__u64 x) +{ + some_var ^= x + bpf_jiffies64(); +} + +SEC("syscall") +int one_switch(struct simple_ctx *ctx) +{ + switch (ctx->x) { + case 0: + adjust_insns(ctx->x + 1); + ret_user = 2; + break; + case 1: + adjust_insns(ctx->x + 7); + ret_user = 3; + break; + case 2: + adjust_insns(ctx->x + 9); + ret_user = 4; + break; + case 3: + adjust_insns(ctx->x + 11); + ret_user = 5; + break; + case 4: + adjust_insns(ctx->x + 17); + ret_user = 7; + break; + default: + adjust_insns(ctx->x + 177); + ret_user = 19; + break; + } + + return 0; +} + +SEC("syscall") +int one_switch_non_zero_sec_off(struct simple_ctx *ctx) +{ + switch (ctx->x) { + case 0: + adjust_insns(ctx->x + 1); + ret_user = 2; + break; + case 1: + adjust_insns(ctx->x + 7); + ret_user = 3; + break; + case 2: + adjust_insns(ctx->x + 9); + ret_user = 4; + break; + case 3: + adjust_insns(ctx->x + 11); + ret_user = 5; + break; + case 4: + adjust_insns(ctx->x + 17); + ret_user = 7; + break; + default: + adjust_insns(ctx->x + 177); + ret_user = 19; + break; + } + + return 0; +} + +SEC("fentry/" SYS_PREFIX "sys_nanosleep") +int simple_test_other_sec(struct pt_regs *ctx) +{ + __u64 x = in_user; + + switch (x) { + case 0: + adjust_insns(x + 1); + ret_user = 2; + break; + case 1: + adjust_insns(x + 7); + ret_user = 3; + break; + case 2: + adjust_insns(x + 9); + ret_user = 4; + break; + case 3: + adjust_insns(x + 11); + ret_user = 5; + break; + case 4: + adjust_insns(x + 17); + ret_user = 7; + break; + default: + adjust_insns(x + 177); + ret_user = 19; + break; + } + + return 0; +} + +SEC("syscall") +int two_switches(struct simple_ctx *ctx) +{ + switch (ctx->x) { + case 0: + adjust_insns(ctx->x + 1); + ret_user = 2; + break; + case 1: + adjust_insns(ctx->x + 7); + ret_user = 3; + break; + case 2: + adjust_insns(ctx->x + 9); + ret_user = 4; + break; + case 3: + adjust_insns(ctx->x + 11); + ret_user = 5; + break; + case 4: + adjust_insns(ctx->x + 17); + ret_user = 7; + break; + default: + adjust_insns(ctx->x + 177); + ret_user = 19; + break; + } + + switch (ctx->x + !!ret_user) { + case 1: + adjust_insns(ctx->x + 7); + ret_user = 103; + break; + case 2: + adjust_insns(ctx->x + 9); + ret_user = 104; + break; + case 3: + adjust_insns(ctx->x + 11); + ret_user = 107; + break; + case 4: + adjust_insns(ctx->x + 11); + ret_user = 205; + break; + case 5: + adjust_insns(ctx->x + 11); + ret_user = 115; + break; + default: + adjust_insns(ctx->x + 177); + ret_user = 1019; + break; + } + + return 0; +} + +SEC("syscall") +int big_jump_table(struct simple_ctx *ctx __attribute__((unused))) +{ + const void *const jt[256] = { + [0 ... 255] = &&default_label, + [0] = &&l0, + [11] = &&l11, + [27] = &&l27, + [31] = &&l31, + }; + + goto *jt[ctx->x & 0xff]; + +l0: + adjust_insns(ctx->x + 1); + ret_user = 2; + return 0; + +l11: + adjust_insns(ctx->x + 7); + ret_user = 3; + return 0; + +l27: + adjust_insns(ctx->x + 9); + ret_user = 4; + return 0; + +l31: + adjust_insns(ctx->x + 11); + ret_user = 5; + return 0; + +default_label: + adjust_insns(ctx->x + 177); + ret_user = 19; + return 0; +} + +SEC("syscall") +int one_jump_two_maps(struct simple_ctx *ctx __attribute__((unused))) +{ + __label__ l1, l2, l3, l4; + void *jt1[2] = { &&l1, &&l2 }; + void *jt2[2] = { &&l3, &&l4 }; + unsigned int a = ctx->x % 2; + unsigned int b = (ctx->x / 2) % 2; + volatile int ret = 0; + + if (!(a < 2 && b < 2)) + return 19; + + if (ctx->x % 2) + goto *jt1[a]; + else + goto *jt2[b]; + + l1: ret += 1; + l2: ret += 3; + l3: ret += 5; + l4: ret += 7; + + ret_user = ret; + return ret; +} + +SEC("syscall") +int one_map_two_jumps(struct simple_ctx *ctx __attribute__((unused))) +{ + __label__ l1, l2, l3; + void *jt[3] = { &&l1, &&l2, &&l3 }; + unsigned int a = (ctx->x >> 2) & 1; + unsigned int b = (ctx->x >> 3) & 1; + volatile int ret = 0; + + if (ctx->x % 2) + goto *jt[a]; + + if (ctx->x % 3) + goto *jt[a + b]; + + l1: ret += 3; + l2: ret += 5; + l3: ret += 7; + + ret_user = ret; + return ret; +} + +/* Just to introduce some non-zero offsets in .text */ +static __noinline int f0(volatile struct simple_ctx *ctx __arg_ctx) +{ + if (ctx) + return 1; + else + return 13; +} + +SEC("syscall") int f1(struct simple_ctx *ctx) +{ + ret_user = 0; + return f0(ctx); +} + +static __noinline int __static_global(__u64 x) +{ + switch (x) { + case 0: + adjust_insns(x + 1); + ret_user = 2; + break; + case 1: + adjust_insns(x + 7); + ret_user = 3; + break; + case 2: + adjust_insns(x + 9); + ret_user = 4; + break; + case 3: + adjust_insns(x + 11); + ret_user = 5; + break; + case 4: + adjust_insns(x + 17); + ret_user = 7; + break; + default: + adjust_insns(x + 177); + ret_user = 19; + break; + } + + return 0; +} + +SEC("syscall") +int use_static_global1(struct simple_ctx *ctx) +{ + ret_user = 0; + return __static_global(ctx->x); +} + +SEC("syscall") +int use_static_global2(struct simple_ctx *ctx) +{ + ret_user = 0; + adjust_insns(ctx->x + 1); + return __static_global(ctx->x); +} + +SEC("fentry/" SYS_PREFIX "sys_nanosleep") +int use_static_global_other_sec(void *ctx) +{ + return __static_global(in_user); +} + +__noinline int __nonstatic_global(__u64 x) +{ + switch (x) { + case 0: + adjust_insns(x + 1); + ret_user = 2; + break; + case 1: + adjust_insns(x + 7); + ret_user = 3; + break; + case 2: + adjust_insns(x + 9); + ret_user = 4; + break; + case 3: + adjust_insns(x + 11); + ret_user = 5; + break; + case 4: + adjust_insns(x + 17); + ret_user = 7; + break; + default: + adjust_insns(x + 177); + ret_user = 19; + break; + } + + return 0; +} + +SEC("syscall") +int use_nonstatic_global1(struct simple_ctx *ctx) +{ + ret_user = 0; + return __nonstatic_global(ctx->x); +} + +SEC("syscall") +int use_nonstatic_global2(struct simple_ctx *ctx) +{ + ret_user = 0; + adjust_insns(ctx->x + 1); + return __nonstatic_global(ctx->x); +} + +SEC("fentry/" SYS_PREFIX "sys_nanosleep") +int use_nonstatic_global_other_sec(void *ctx) +{ + return __nonstatic_global(in_user); +} +#endif + +char _license[] SEC("license") = "GPL"; -- 2.34.1