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[compiler-rt] change internal internal libc invariants
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llvm-libc is expected to be built with sanitizers and not use interceptors in
the long run. For now though, we have a hybrid process, where functions
implemented in llvm-libc are instrumented, and glibc fills and sanitizer
interceptors fill in the rest.

Current sanitizers have an invariant that the REAL(...) function called from
inside of an interceptor is uninstrumented. A lot of interceptors call strlen()
in order to figure out the size of the region to check/poison. Switch these
callsites over to the internal, unsanitized implementation.

Reviewed By: hctim, vitalybuka

Differential Revision: https://reviews.llvm.org/D108316
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@michaelrj-google
michaelrj-google committed Aug 24, 2021
1 parent b232a88 commit 40067b8
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Showing 8 changed files with 290 additions and 256 deletions.
16 changes: 8 additions & 8 deletions compiler-rt/lib/asan/asan_interceptors.cpp
View file
Expand Up @@ -49,8 +49,8 @@ namespace __asan {
ASAN_READ_RANGE((ctx), (s), \
common_flags()->strict_string_checks ? (len) + 1 : (n))

#define ASAN_READ_STRING(ctx, s, n) \
ASAN_READ_STRING_OF_LEN((ctx), (s), REAL(strlen)(s), (n))
# define ASAN_READ_STRING(ctx, s, n) \
ASAN_READ_STRING_OF_LEN((ctx), (s), internal_strlen(s), (n))

static inline uptr MaybeRealStrnlen(const char *s, uptr maxlen) {
#if SANITIZER_INTERCEPT_STRNLEN
Expand Down Expand Up @@ -370,9 +370,9 @@ DEFINE_REAL(char*, index, const char *string, int c)
ASAN_INTERCEPTOR_ENTER(ctx, strcat);
ENSURE_ASAN_INITED();
if (flags()->replace_str) {
uptr from_length = REAL(strlen)(from);
uptr from_length = internal_strlen(from);
ASAN_READ_RANGE(ctx, from, from_length + 1);
uptr to_length = REAL(strlen)(to);
uptr to_length = internal_strlen(to);
ASAN_READ_STRING_OF_LEN(ctx, to, to_length, to_length);
ASAN_WRITE_RANGE(ctx, to + to_length, from_length + 1);
// If the copying actually happens, the |from| string should not overlap
Expand All @@ -394,7 +394,7 @@ INTERCEPTOR(char*, strncat, char *to, const char *from, uptr size) {
uptr from_length = MaybeRealStrnlen(from, size);
uptr copy_length = Min(size, from_length + 1);
ASAN_READ_RANGE(ctx, from, copy_length);
uptr to_length = REAL(strlen)(to);
uptr to_length = internal_strlen(to);
ASAN_READ_STRING_OF_LEN(ctx, to, to_length, to_length);
ASAN_WRITE_RANGE(ctx, to + to_length, from_length + 1);
if (from_length > 0) {
Expand All @@ -419,7 +419,7 @@ INTERCEPTOR(char *, strcpy, char *to, const char *from) {
}
ENSURE_ASAN_INITED();
if (flags()->replace_str) {
uptr from_size = REAL(strlen)(from) + 1;
uptr from_size = internal_strlen(from) + 1;
CHECK_RANGES_OVERLAP("strcpy", to, from_size, from, from_size);
ASAN_READ_RANGE(ctx, from, from_size);
ASAN_WRITE_RANGE(ctx, to, from_size);
Expand All @@ -432,7 +432,7 @@ INTERCEPTOR(char*, strdup, const char *s) {
ASAN_INTERCEPTOR_ENTER(ctx, strdup);
if (UNLIKELY(!asan_inited)) return internal_strdup(s);
ENSURE_ASAN_INITED();
uptr length = REAL(strlen)(s);
uptr length = internal_strlen(s);
if (flags()->replace_str) {
ASAN_READ_RANGE(ctx, s, length + 1);
}
Expand All @@ -448,7 +448,7 @@ INTERCEPTOR(char*, __strdup, const char *s) {
ASAN_INTERCEPTOR_ENTER(ctx, strdup);
if (UNLIKELY(!asan_inited)) return internal_strdup(s);
ENSURE_ASAN_INITED();
uptr length = REAL(strlen)(s);
uptr length = internal_strlen(s);
if (flags()->replace_str) {
ASAN_READ_RANGE(ctx, s, length + 1);
}
Expand Down
12 changes: 6 additions & 6 deletions compiler-rt/lib/memprof/memprof_interceptors.cpp
View file
Expand Up @@ -204,9 +204,9 @@ INTERCEPTOR(char *, strcat, char *to, const char *from) {
void *ctx;
MEMPROF_INTERCEPTOR_ENTER(ctx, strcat);
ENSURE_MEMPROF_INITED();
uptr from_length = REAL(strlen)(from);
uptr from_length = internal_strlen(from);
MEMPROF_READ_RANGE(from, from_length + 1);
uptr to_length = REAL(strlen)(to);
uptr to_length = internal_strlen(to);
MEMPROF_READ_STRING(to, to_length);
MEMPROF_WRITE_RANGE(to + to_length, from_length + 1);
return REAL(strcat)(to, from);
Expand All @@ -219,7 +219,7 @@ INTERCEPTOR(char *, strncat, char *to, const char *from, uptr size) {
uptr from_length = MaybeRealStrnlen(from, size);
uptr copy_length = Min(size, from_length + 1);
MEMPROF_READ_RANGE(from, copy_length);
uptr to_length = REAL(strlen)(to);
uptr to_length = internal_strlen(to);
MEMPROF_READ_STRING(to, to_length);
MEMPROF_WRITE_RANGE(to + to_length, from_length + 1);
return REAL(strncat)(to, from, size);
Expand All @@ -232,7 +232,7 @@ INTERCEPTOR(char *, strcpy, char *to, const char *from) {
return REAL(strcpy)(to, from);
}
ENSURE_MEMPROF_INITED();
uptr from_size = REAL(strlen)(from) + 1;
uptr from_size = internal_strlen(from) + 1;
MEMPROF_READ_RANGE(from, from_size);
MEMPROF_WRITE_RANGE(to, from_size);
return REAL(strcpy)(to, from);
Expand All @@ -244,7 +244,7 @@ INTERCEPTOR(char *, strdup, const char *s) {
if (UNLIKELY(!memprof_inited))
return internal_strdup(s);
ENSURE_MEMPROF_INITED();
uptr length = REAL(strlen)(s);
uptr length = internal_strlen(s);
MEMPROF_READ_RANGE(s, length + 1);
GET_STACK_TRACE_MALLOC;
void *new_mem = memprof_malloc(length + 1, &stack);
Expand All @@ -258,7 +258,7 @@ INTERCEPTOR(char *, __strdup, const char *s) {
if (UNLIKELY(!memprof_inited))
return internal_strdup(s);
ENSURE_MEMPROF_INITED();
uptr length = REAL(strlen)(s);
uptr length = internal_strlen(s);
MEMPROF_READ_RANGE(s, length + 1);
GET_STACK_TRACE_MALLOC;
void *new_mem = memprof_malloc(length + 1, &stack);
Expand Down
51 changes: 27 additions & 24 deletions compiler-rt/lib/msan/msan_interceptors.cpp
View file
Expand Up @@ -286,7 +286,7 @@ INTERCEPTOR(void, malloc_stats, void) {
INTERCEPTOR(char *, strcpy, char *dest, const char *src) {
ENSURE_MSAN_INITED();
GET_STORE_STACK_TRACE;
SIZE_T n = REAL(strlen)(src);
SIZE_T n = internal_strlen(src);
CHECK_UNPOISONED_STRING(src + n, 0);
char *res = REAL(strcpy)(dest, src);
CopyShadowAndOrigin(dest, src, n + 1, &stack);
Expand All @@ -296,7 +296,7 @@ INTERCEPTOR(char *, strcpy, char *dest, const char *src) {
INTERCEPTOR(char *, strncpy, char *dest, const char *src, SIZE_T n) {
ENSURE_MSAN_INITED();
GET_STORE_STACK_TRACE;
SIZE_T copy_size = REAL(strnlen)(src, n);
SIZE_T copy_size = internal_strnlen(src, n);
if (copy_size < n)
copy_size++; // trailing \0
char *res = REAL(strncpy)(dest, src, n);
Expand All @@ -309,7 +309,7 @@ INTERCEPTOR(char *, strncpy, char *dest, const char *src, SIZE_T n) {
INTERCEPTOR(char *, stpcpy, char *dest, const char *src) {
ENSURE_MSAN_INITED();
GET_STORE_STACK_TRACE;
SIZE_T n = REAL(strlen)(src);
SIZE_T n = internal_strlen(src);
CHECK_UNPOISONED_STRING(src + n, 0);
char *res = REAL(stpcpy)(dest, src);
CopyShadowAndOrigin(dest, src, n + 1, &stack);
Expand All @@ -325,7 +325,7 @@ INTERCEPTOR(char *, strdup, char *src) {
GET_STORE_STACK_TRACE;
// On FreeBSD strdup() leverages strlen().
InterceptorScope interceptor_scope;
SIZE_T n = REAL(strlen)(src);
SIZE_T n = internal_strlen(src);
CHECK_UNPOISONED_STRING(src + n, 0);
char *res = REAL(strdup)(src);
CopyShadowAndOrigin(res, src, n + 1, &stack);
Expand All @@ -336,7 +336,7 @@ INTERCEPTOR(char *, strdup, char *src) {
INTERCEPTOR(char *, __strdup, char *src) {
ENSURE_MSAN_INITED();
GET_STORE_STACK_TRACE;
SIZE_T n = REAL(strlen)(src);
SIZE_T n = internal_strlen(src);
CHECK_UNPOISONED_STRING(src + n, 0);
char *res = REAL(__strdup)(src);
CopyShadowAndOrigin(res, src, n + 1, &stack);
Expand All @@ -351,7 +351,7 @@ INTERCEPTOR(char *, __strdup, char *src) {
INTERCEPTOR(char *, gcvt, double number, SIZE_T ndigit, char *buf) {
ENSURE_MSAN_INITED();
char *res = REAL(gcvt)(number, ndigit, buf);
SIZE_T n = REAL(strlen)(buf);
SIZE_T n = internal_strlen(buf);
__msan_unpoison(buf, n + 1);
return res;
}
Expand All @@ -363,8 +363,8 @@ INTERCEPTOR(char *, gcvt, double number, SIZE_T ndigit, char *buf) {
INTERCEPTOR(char *, strcat, char *dest, const char *src) {
ENSURE_MSAN_INITED();
GET_STORE_STACK_TRACE;
SIZE_T src_size = REAL(strlen)(src);
SIZE_T dest_size = REAL(strlen)(dest);
SIZE_T src_size = internal_strlen(src);
SIZE_T dest_size = internal_strlen(dest);
CHECK_UNPOISONED_STRING(src + src_size, 0);
CHECK_UNPOISONED_STRING(dest + dest_size, 0);
char *res = REAL(strcat)(dest, src);
Expand All @@ -375,8 +375,8 @@ INTERCEPTOR(char *, strcat, char *dest, const char *src) {
INTERCEPTOR(char *, strncat, char *dest, const char *src, SIZE_T n) {
ENSURE_MSAN_INITED();
GET_STORE_STACK_TRACE;
SIZE_T dest_size = REAL(strlen)(dest);
SIZE_T copy_size = REAL(strnlen)(src, n);
SIZE_T dest_size = internal_strlen(dest);
SIZE_T copy_size = internal_strnlen(src, n);
CHECK_UNPOISONED_STRING(dest + dest_size, 0);
char *res = REAL(strncat)(dest, src, n);
CopyShadowAndOrigin(dest + dest_size, src, copy_size, &stack);
Expand Down Expand Up @@ -612,7 +612,8 @@ INTERCEPTOR(char *, fcvt, double x, int a, int *b, int *c) {
char *res = REAL(fcvt)(x, a, b, c);
__msan_unpoison(b, sizeof(*b));
__msan_unpoison(c, sizeof(*c));
if (res) __msan_unpoison(res, REAL(strlen)(res) + 1);
if (res)
__msan_unpoison(res, internal_strlen(res) + 1);
return res;
}
#define MSAN_MAYBE_INTERCEPT_FCVT INTERCEPT_FUNCTION(fcvt)
Expand All @@ -625,7 +626,8 @@ INTERCEPTOR(char *, getenv, char *name) {
return REAL(getenv)(name);
ENSURE_MSAN_INITED();
char *res = REAL(getenv)(name);
if (res) __msan_unpoison(res, REAL(strlen)(res) + 1);
if (res)
__msan_unpoison(res, internal_strlen(res) + 1);
return res;
}

Expand All @@ -635,7 +637,7 @@ static void UnpoisonEnviron() {
char **envp = environ;
for (; *envp; ++envp) {
__msan_unpoison(envp, sizeof(*envp));
__msan_unpoison(*envp, REAL(strlen)(*envp) + 1);
__msan_unpoison(*envp, internal_strlen(*envp) + 1);
}
// Trailing NULL pointer.
__msan_unpoison(envp, sizeof(*envp));
Expand Down Expand Up @@ -758,7 +760,7 @@ INTERCEPTOR(char *, fgets_unlocked, char *s, int size, void *stream) {
ENSURE_MSAN_INITED();
char *res = REAL(fgets_unlocked)(s, size, stream);
if (res)
__msan_unpoison(s, REAL(strlen)(s) + 1);
__msan_unpoison(s, internal_strlen(s) + 1);
return res;
}
#define MSAN_MAYBE_INTERCEPT_FGETS_UNLOCKED INTERCEPT_FUNCTION(fgets_unlocked)
Expand Down Expand Up @@ -829,7 +831,7 @@ INTERCEPTOR(int, gethostname, char *name, SIZE_T len) {
ENSURE_MSAN_INITED();
int res = REAL(gethostname)(name, len);
if (!res || (res == -1 && errno == errno_ENAMETOOLONG)) {
SIZE_T real_len = REAL(strnlen)(name, len);
SIZE_T real_len = internal_strnlen(name, len);
if (real_len < len)
++real_len;
__msan_unpoison(name, real_len);
Expand Down Expand Up @@ -1080,9 +1082,9 @@ INTERCEPTOR(void, tzset, int fake) {
InterceptorScope interceptor_scope;
REAL(tzset)(fake);
if (tzname[0])
__msan_unpoison(tzname[0], REAL(strlen)(tzname[0]) + 1);
__msan_unpoison(tzname[0], internal_strlen(tzname[0]) + 1);
if (tzname[1])
__msan_unpoison(tzname[1], REAL(strlen)(tzname[1]) + 1);
__msan_unpoison(tzname[1], internal_strlen(tzname[1]) + 1);
return;
}

Expand Down Expand Up @@ -1455,9 +1457,9 @@ INTERCEPTOR(int, dladdr, void *addr, dlinfo *info) {
if (res != 0) {
__msan_unpoison(info, sizeof(*info));
if (info->dli_fname)
__msan_unpoison(info->dli_fname, REAL(strlen)(info->dli_fname) + 1);
__msan_unpoison(info->dli_fname, internal_strlen(info->dli_fname) + 1);
if (info->dli_sname)
__msan_unpoison(info->dli_sname, REAL(strlen)(info->dli_sname) + 1);
__msan_unpoison(info->dli_sname, internal_strlen(info->dli_sname) + 1);
}
return res;
}
Expand All @@ -1466,7 +1468,8 @@ INTERCEPTOR(char *, dlerror, int fake) {
void *ctx;
COMMON_INTERCEPTOR_ENTER(ctx, dlerror, fake);
char *res = REAL(dlerror)(fake);
if (res) __msan_unpoison(res, REAL(strlen)(res) + 1);
if (res)
__msan_unpoison(res, internal_strlen(res) + 1);
return res;
}

Expand All @@ -1484,7 +1487,7 @@ static int msan_dl_iterate_phdr_cb(__sanitizer_dl_phdr_info *info, SIZE_T size,
if (info->dlpi_phdr && info->dlpi_phnum)
__msan_unpoison(info->dlpi_phdr, struct_ElfW_Phdr_sz * info->dlpi_phnum);
if (info->dlpi_name)
__msan_unpoison(info->dlpi_name, REAL(strlen)(info->dlpi_name) + 1);
__msan_unpoison(info->dlpi_name, internal_strlen(info->dlpi_name) + 1);
}
dl_iterate_phdr_data *cbdata = (dl_iterate_phdr_data *)data;
UnpoisonParam(3);
Expand Down Expand Up @@ -1526,15 +1529,15 @@ INTERCEPTOR(wchar_t *, wcscpy, wchar_t *dest, const wchar_t *src) {
ENSURE_MSAN_INITED();
GET_STORE_STACK_TRACE;
wchar_t *res = REAL(wcscpy)(dest, src);
CopyShadowAndOrigin(dest, src, sizeof(wchar_t) * (REAL(wcslen)(src) + 1),
CopyShadowAndOrigin(dest, src, sizeof(wchar_t) * (internal_wcslen(src) + 1),
&stack);
return res;
}

INTERCEPTOR(wchar_t *, wcsncpy, wchar_t *dest, const wchar_t *src, SIZE_T n) {
ENSURE_MSAN_INITED();
GET_STORE_STACK_TRACE;
SIZE_T copy_size = REAL(wcsnlen)(src, n);
SIZE_T copy_size = internal_wcsnlen(src, n);
if (copy_size < n) copy_size++; // trailing \0
wchar_t *res = REAL(wcsncpy)(dest, src, n);
CopyShadowAndOrigin(dest, src, copy_size * sizeof(wchar_t), &stack);
Expand Down Expand Up @@ -1598,7 +1601,7 @@ void *__msan_memmove(void *dest, const void *src, SIZE_T n) {

void __msan_unpoison_string(const char* s) {
if (!MEM_IS_APP(s)) return;
__msan_unpoison(s, REAL(strlen)(s) + 1);
__msan_unpoison(s, internal_strlen(s) + 1);
}

namespace __msan {
Expand Down

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