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