Expand the arena library selftest infrastructure to support address sanitization. Add the compiler flags necessary to compile the library under ASAN when supported. Signed-off-by: Emil Tsalapatis --- tools/testing/selftests/bpf/Makefile | 22 +++++++- tools/testing/selftests/bpf/libarena/Makefile | 25 ++++++++- .../bpf/libarena/include/libarena/userspace.h | 33 ++++++++++++ .../bpf/libarena/selftests/st_asan_common.h | 52 +++++++++++++++++++ .../selftests/bpf/libarena/src/common.bpf.c | 2 + 5 files changed, 132 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/libarena/selftests/st_asan_common.h diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 13959c449893..8f694131118c 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -79,6 +79,12 @@ ifneq ($(shell $(CLANG) --target=bpf -mcpu=help 2>&1 | grep 'v4'),) CLANG_CPUV4 := 1 endif +# Check whether clang supports BPF address sanitizer (requires LLVM 22+) +CLANG_HAS_ARENA_ASAN := $(shell echo 'int x;' | \ + $(CLANG) --target=bpf -fsanitize=kernel-address \ + -mllvm -asan-shadow-addr-space=1 \ + -x c -c - -o /dev/null 2>/dev/null && echo 1) + # Order correspond to 'make run_tests' order TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_progs \ test_sockmap \ @@ -767,6 +773,14 @@ LIBARENA_SKEL := libarena/libarena.skel.h $(LIBARENA_SKEL): $(INCLUDE_DIR)/vmlinux.h $(BPFOBJ) $(LIBARENA_BPF_DEPS) +$(MAKE) -C libarena libarena.skel.h $(LIBARENA_MAKE_ARGS) +ifneq ($(CLANG_HAS_ARENA_ASAN),) +LIBARENA_ASAN_SKEL := libarena/libarena_asan.skel.h +CFLAGS += -DHAS_BPF_ARENA_ASAN + +$(LIBARENA_ASAN_SKEL): $(INCLUDE_DIR)/vmlinux.h $(BPFOBJ) $(LIBARENA_BPF_DEPS) + +$(MAKE) -C libarena libarena_asan.skel.h $(LIBARENA_MAKE_ARGS) +endif + # Define test_progs test runner. TRUNNER_TESTS_DIR := prog_tests TRUNNER_BPF_PROGS_DIR := progs @@ -791,7 +805,9 @@ TRUNNER_EXTRA_SOURCES := test_progs.c \ flow_dissector_load.h \ ip_check_defrag_frags.h \ bpftool_helpers.c \ - usdt_1.c usdt_2.c + usdt_1.c usdt_2.c \ + $(LIBARENA_SKEL) \ + $(LIBARENA_ASAN_SKEL) TRUNNER_LIB_SOURCES := find_bit.c TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read \ $(OUTPUT)/liburandom_read.so \ @@ -962,3 +978,7 @@ override define INSTALL_RULE endef libarena: $(LIBARENA_SKEL) + +ifneq ($(CLANG_HAS_ARENA_ASAN),) +libarena_asan: $(LIBARENA_ASAN_SKEL) +endif diff --git a/tools/testing/selftests/bpf/libarena/Makefile b/tools/testing/selftests/bpf/libarena/Makefile index e85b3ad96890..5e2ab514805e 100644 --- a/tools/testing/selftests/bpf/libarena/Makefile +++ b/tools/testing/selftests/bpf/libarena/Makefile @@ -30,6 +30,7 @@ LIBBPF_INCLUDE ?= $(INCLUDE_DIR) # Scan src/ and selftests/ to generate the final binaries LIBARENA_SOURCES = $(wildcard $(LIBARENA)/src/*.bpf.c) $(wildcard $(LIBARENA)/selftests/*.bpf.c) LIBARENA_OBJECTS = $(notdir $(LIBARENA_SOURCES:.bpf.c=.bpf.o)) +LIBARENA_OBJECTS_ASAN = $(notdir $(LIBARENA_SOURCES:.bpf.c=_asan.bpf.o)) INCLUDES = -I$(LIBARENA)/include -I$(BPFDIR) ifneq ($(INCLUDE_DIR),) @@ -39,6 +40,13 @@ ifneq ($(LIBBPF_INCLUDE),) INCLUDES += -I$(LIBBPF_INCLUDE) endif +ASAN_FLAGS = -fsanitize=kernel-address -fno-stack-protector -fno-builtin +ASAN_FLAGS += -mllvm -asan-instrument-address-spaces=1 -mllvm -asan-shadow-addr-space=1 +ASAN_FLAGS += -mllvm -asan-use-stack-safety=0 -mllvm -asan-stack=0 +ASAN_FLAGS += -mllvm -asan-kernel=1 +ASAN_FLAGS += -mllvm -asan-constructor-kind=none +ASAN_FLAGS += -mllvm -asan-destructor-kind=none + # ENABLE_ATOMICS_TESTS required because we use arena spinlocks override BPF_CFLAGS += -DENABLE_ATOMICS_TESTS override BPF_CFLAGS += -O2 -g @@ -53,17 +61,32 @@ CFLAGS += $(INCLUDES) vpath %.bpf.c $(LIBARENA)/src $(LIBARENA)/selftests vpath %.c $(LIBARENA)/src $(LIBARENA)/selftests +skeletons: libarena.skel.h libarena_asan.skel.h +.PHONY: skeletons + +libarena_asan.skel.h: libarena_asan.bpf.o + $(call msg,GEN-SKEL,libarena,$@) + $(Q)$(BPFTOOL) gen skeleton $< name "libarena_asan" > $@ + libarena.skel.h: libarena.bpf.o $(call msg,GEN-SKEL,libarena,$@) $(Q)$(BPFTOOL) gen skeleton $< name "libarena" > $@ +libarena_asan.bpf.o: $(LIBARENA_OBJECTS_ASAN) + $(call msg,GEN-OBJ,libarena,$@) + $(Q)$(BPFTOOL) gen object $@ $^ + libarena.bpf.o: $(LIBARENA_OBJECTS) $(call msg,GEN-OBJ,libarena,$@) $(Q)$(BPFTOOL) gen object $@ $^ +%_asan.bpf.o: %.bpf.c + $(call msg,CLNG-BPF,libarena,$@) + $(Q)$(CLANG) $(BPF_CFLAGS) $(ASAN_FLAGS) -DBPF_ARENA_ASAN $(BPF_TARGET_ENDIAN) -c $< -o $@ + %.bpf.o: %.bpf.c $(call msg,CLNG-BPF,libarena,$@) $(Q)$(CLANG) $(BPF_CFLAGS) $(BPF_TARGET_ENDIAN) -c $< -o $@ clean: - $(Q)rm -f *.skel.h *.bpf.o + $(Q)rm -f *.skel.h *.bpf.o *.linked*.o diff --git a/tools/testing/selftests/bpf/libarena/include/libarena/userspace.h b/tools/testing/selftests/bpf/libarena/include/libarena/userspace.h index 0438a751d5fd..88b68ac73cca 100644 --- a/tools/testing/selftests/bpf/libarena/include/libarena/userspace.h +++ b/tools/testing/selftests/bpf/libarena/include/libarena/userspace.h @@ -27,6 +27,11 @@ static inline bool libarena_is_test_prog(const char *name) return strstr(name, "test_") == name; } +static inline bool libarena_is_asan_test_prog(const char *name) +{ + return strstr(name, "asan_test") == name; +} + static inline int libarena_run_prog_args(int prog_fd, void *args, size_t argsize) { LIBBPF_OPTS(bpf_test_run_opts, opts); @@ -97,3 +102,31 @@ static inline int libarena_get_globals_pages(int arena_get_globals_fd, free(vec); return 0; } + +static inline int libarena_asan_init(int arena_asan_init_fd, + int asan_init_fd, + size_t arena_all_pages) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts); + struct asan_init_args args; + u64 globals_pages; + int ret; + + ret = libarena_get_globals_pages(arena_asan_init_fd, + arena_all_pages, &globals_pages); + if (ret) + return ret; + + args = (struct asan_init_args){ + .arena_all_pages = arena_all_pages, + .arena_globals_pages = globals_pages, + }; + + opts.ctx_in = &args; + opts.ctx_size_in = sizeof(args); + + ret = bpf_prog_test_run_opts(asan_init_fd, &opts); + if (ret) + return ret; + return opts.retval; +} diff --git a/tools/testing/selftests/bpf/libarena/selftests/st_asan_common.h b/tools/testing/selftests/bpf/libarena/selftests/st_asan_common.h new file mode 100644 index 000000000000..1d3edc4372ac --- /dev/null +++ b/tools/testing/selftests/bpf/libarena/selftests/st_asan_common.h @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: LGPL-2.1 OR BSD-2-Clause +/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ + +#pragma once + +#define ST_PAGES 64 + +static inline void print_asan_map_state(void __arena *addr) +{ + arena_stdout("%s:%d ASAN %p -> (val: %x gran: %x set: [%s])", + __func__, __LINE__, addr, + *(s8a *)(addr), ASAN_GRANULE(addr), + asan_shadow_set(addr) ? "yes" : "no"); +} + +/* + * Emit an error and force the current function to exit if the ASAN + * violation state is unexpected. Reset the violation state after. + */ +static inline int asan_validate_addr(bool cond, void __arena *addr) +{ + if ((asan_violated != 0) == cond) { + asan_violated = 0; + return 0; + } + + arena_stdout("%s:%d ASAN asan_violated %lx", __func__, __LINE__, + (u64)asan_violated); + print_asan_map_state(addr); + + asan_violated = 0; + + return -EINVAL; +} + +static inline int asan_validate(void) +{ + if (!asan_violated) + return 0; + + arena_stdout("%s:%d Found ASAN violation at %lx", __func__, __LINE__, + asan_violated); + + asan_violated = 0; + + return -EINVAL; +} + +struct blob { + volatile u8 mem[59]; + u8 oob; +}; diff --git a/tools/testing/selftests/bpf/libarena/src/common.bpf.c b/tools/testing/selftests/bpf/libarena/src/common.bpf.c index 659ccead5624..84e8a8b7d42e 100644 --- a/tools/testing/selftests/bpf/libarena/src/common.bpf.c +++ b/tools/testing/selftests/bpf/libarena/src/common.bpf.c @@ -2,6 +2,8 @@ /* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ #include +#include + const volatile u32 zero = 0; int arena_fls(__u64 word) -- 2.53.0