diff options
Diffstat (limited to '0009-x86emul-rework-wrapping-of-libc-functions-in-test-an.patch')
| -rw-r--r-- | 0009-x86emul-rework-wrapping-of-libc-functions-in-test-an.patch | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/0009-x86emul-rework-wrapping-of-libc-functions-in-test-an.patch b/0009-x86emul-rework-wrapping-of-libc-functions-in-test-an.patch new file mode 100644 index 0000000..4f9c0bb --- /dev/null +++ b/0009-x86emul-rework-wrapping-of-libc-functions-in-test-an.patch @@ -0,0 +1,245 @@ +From 37f1d68fa34220600f1e4ec82af5da70127757e5 Mon Sep 17 00:00:00 2001 +From: Jan Beulich <jbeulich@suse.com> +Date: Fri, 18 Aug 2023 15:04:28 +0200 +Subject: [PATCH 09/55] x86emul: rework wrapping of libc functions in test and + fuzzing harnesses + +Our present approach is working fully behind the compiler's back. This +was found to not work with LTO. Employ ld's --wrap= option instead. Note +that while this makes the build work at least with new enough gcc (it +doesn't with gcc7, for example, due to tool chain side issues afaict), +according to my testing things still won't work when building the +fuzzing harness with afl-cc: While with the gcc7 tool chain I see afl-as +getting invoked, this does not happen with gcc13. Yet without using that +assembler wrapper the resulting binary will look uninstrumented to +afl-fuzz. + +While checking the resulting binaries I noticed that we've gained uses +of snprintf() and strstr(), which only just so happen to not cause any +problems. Add a wrappers for them as well. + +Since we don't have any actual uses of v{,sn}printf(), no definitions of +their wrappers appear (just yet). But I think we want +__wrap_{,sn}printf() to properly use __real_v{,sn}printf() right away, +which means we need delarations of the latter. + +Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> +Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com> +Signed-off-by: Jan Beulich <jbeulich@suse.com> +Tested-by: Andrew Cooper <andrew.cooper3@citrix.com> +Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> +(cherry picked from commit 6fba45ca3be1c5d46cddb1eaf371d9e69550b244) +--- + tools/fuzz/x86_instruction_emulator/Makefile | 6 ++- + tools/tests/x86_emulator/Makefile | 4 +- + tools/tests/x86_emulator/wrappers.c | 55 ++++++++++++++------ + tools/tests/x86_emulator/x86-emulate.h | 14 +++-- + 4 files changed, 53 insertions(+), 26 deletions(-) + +diff --git a/tools/fuzz/x86_instruction_emulator/Makefile b/tools/fuzz/x86_instruction_emulator/Makefile +index 13aa238503..c83959c847 100644 +--- a/tools/fuzz/x86_instruction_emulator/Makefile ++++ b/tools/fuzz/x86_instruction_emulator/Makefile +@@ -29,6 +29,8 @@ GCOV_FLAGS := --coverage + %-cov.o: %.c + $(CC) -c $(CFLAGS) $(GCOV_FLAGS) $< -o $@ + ++WRAPPED = $(shell sed -n 's,^ *WRAP(\([[:alnum:]_]*\));,\1,p' x86-emulate.h) ++ + x86-emulate.h: x86_emulate/x86_emulate.h + x86-emulate.o x86-emulate-cov.o: x86-emulate.h x86_emulate/x86_emulate.c + fuzz-emul.o fuzz-emul-cov.o wrappers.o: x86-emulate.h +@@ -37,10 +39,10 @@ x86-insn-fuzzer.a: fuzz-emul.o x86-emulate.o cpuid.o + $(AR) rc $@ $^ + + afl-harness: afl-harness.o fuzz-emul.o x86-emulate.o cpuid.o wrappers.o +- $(CC) $(CFLAGS) $^ -o $@ ++ $(CC) $(CFLAGS) $(addprefix -Wl$(comma)--wrap=,$(WRAPPED)) $^ -o $@ + + afl-harness-cov: afl-harness-cov.o fuzz-emul-cov.o x86-emulate-cov.o cpuid.o wrappers.o +- $(CC) $(CFLAGS) $(GCOV_FLAGS) $^ -o $@ ++ $(CC) $(CFLAGS) $(GCOV_FLAGS) $(addprefix -Wl$(comma)--wrap=,$(WRAPPED)) $^ -o $@ + + # Common targets + .PHONY: all +diff --git a/tools/tests/x86_emulator/Makefile b/tools/tests/x86_emulator/Makefile +index bd82598f97..a2fd6607c6 100644 +--- a/tools/tests/x86_emulator/Makefile ++++ b/tools/tests/x86_emulator/Makefile +@@ -250,8 +250,10 @@ xop.h avx512f.h: simd-fma.c + + endif # 32-bit override + ++WRAPPED := $(shell sed -n 's,^ *WRAP(\([[:alnum:]_]*\));,\1,p' x86-emulate.h) ++ + $(TARGET): x86-emulate.o cpuid.o test_x86_emulator.o evex-disp8.o predicates.o wrappers.o +- $(HOSTCC) $(HOSTCFLAGS) -o $@ $^ ++ $(HOSTCC) $(HOSTCFLAGS) $(addprefix -Wl$(comma)--wrap=,$(WRAPPED)) -o $@ $^ + + .PHONY: clean + clean: +diff --git a/tools/tests/x86_emulator/wrappers.c b/tools/tests/x86_emulator/wrappers.c +index eba7cc93c5..3829a6f416 100644 +--- a/tools/tests/x86_emulator/wrappers.c ++++ b/tools/tests/x86_emulator/wrappers.c +@@ -1,78 +1,103 @@ + #include <stdarg.h> + +-#define WRAP(x) typeof(x) emul_##x ++#define WRAP(x) typeof(x) __wrap_ ## x, __real_ ## x + #include "x86-emulate.h" + +-size_t emul_fwrite(const void *src, size_t sz, size_t n, FILE *f) ++size_t __wrap_fwrite(const void *src, size_t sz, size_t n, FILE *f) + { + emul_save_fpu_state(); +- sz = fwrite(src, sz, n, f); ++ sz = __real_fwrite(src, sz, n, f); + emul_restore_fpu_state(); + + return sz; + } + +-int emul_memcmp(const void *p1, const void *p2, size_t sz) ++int __wrap_memcmp(const void *p1, const void *p2, size_t sz) + { + int rc; + + emul_save_fpu_state(); +- rc = memcmp(p1, p2, sz); ++ rc = __real_memcmp(p1, p2, sz); + emul_restore_fpu_state(); + + return rc; + } + +-void *emul_memcpy(void *dst, const void *src, size_t sz) ++void *__wrap_memcpy(void *dst, const void *src, size_t sz) + { + emul_save_fpu_state(); +- memcpy(dst, src, sz); ++ __real_memcpy(dst, src, sz); + emul_restore_fpu_state(); + + return dst; + } + +-void *emul_memset(void *dst, int c, size_t sz) ++void *__wrap_memset(void *dst, int c, size_t sz) + { + emul_save_fpu_state(); +- memset(dst, c, sz); ++ __real_memset(dst, c, sz); + emul_restore_fpu_state(); + + return dst; + } + +-int emul_printf(const char *fmt, ...) ++int __wrap_printf(const char *fmt, ...) + { + va_list varg; + int rc; + + emul_save_fpu_state(); + va_start(varg, fmt); +- rc = vprintf(fmt, varg); ++ rc = __real_vprintf(fmt, varg); + va_end(varg); + emul_restore_fpu_state(); + + return rc; + } + +-int emul_putchar(int c) ++int __wrap_putchar(int c) + { + int rc; + + emul_save_fpu_state(); +- rc = putchar(c); ++ rc = __real_putchar(c); + emul_restore_fpu_state(); + + return rc; + } + +-int emul_puts(const char *str) ++int __wrap_puts(const char *str) + { + int rc; + + emul_save_fpu_state(); +- rc = puts(str); ++ rc = __real_puts(str); + emul_restore_fpu_state(); + + return rc; + } ++ ++int __wrap_snprintf(char *buf, size_t n, const char *fmt, ...) ++{ ++ va_list varg; ++ int rc; ++ ++ emul_save_fpu_state(); ++ va_start(varg, fmt); ++ rc = __real_vsnprintf(buf, n, fmt, varg); ++ va_end(varg); ++ emul_restore_fpu_state(); ++ ++ return rc; ++} ++ ++char *__wrap_strstr(const char *s1, const char *s2) ++{ ++ char *s; ++ ++ emul_save_fpu_state(); ++ s = __real_strstr(s1, s2); ++ emul_restore_fpu_state(); ++ ++ return s; ++} +diff --git a/tools/tests/x86_emulator/x86-emulate.h b/tools/tests/x86_emulator/x86-emulate.h +index 19bea9c38d..58760f096d 100644 +--- a/tools/tests/x86_emulator/x86-emulate.h ++++ b/tools/tests/x86_emulator/x86-emulate.h +@@ -29,9 +29,7 @@ + #ifdef EOF + # error "Must not include <stdio.h> before x86-emulate.h" + #endif +-#ifdef WRAP +-# include <stdio.h> +-#endif ++#include <stdio.h> + + #include <xen/xen.h> + +@@ -85,11 +83,7 @@ void emul_restore_fpu_state(void); + * around the actual function. + */ + #ifndef WRAP +-# if 0 /* This only works for explicit calls, not for compiler generated ones. */ +-# define WRAP(x) typeof(x) x asm("emul_" #x) +-# else +-# define WRAP(x) asm(".equ " #x ", emul_" #x) +-# endif ++# define WRAP(x) typeof(x) __wrap_ ## x + #endif + + WRAP(fwrite); +@@ -99,6 +93,10 @@ WRAP(memset); + WRAP(printf); + WRAP(putchar); + WRAP(puts); ++WRAP(snprintf); ++WRAP(strstr); ++WRAP(vprintf); ++WRAP(vsnprintf); + + #undef WRAP + +-- +2.42.0 + |