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| author | Qian Cai <quic_qiancai@quicinc.com> | 2021-10-25 17:05:28 -0400 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2021-10-25 15:34:41 -0700 |
| commit | 95cadae320be46583078690ac89ffe63c95cc9d2 (patch) | |
| tree | f2ba7d7a5a2f2689e1df7ee942feacec54162c9e | |
| parent | 9a48e7564ac83fb0f1d5b0eac5fe8a7af62da398 (diff) | |
fortify: strlen: Avoid shadowing previous locals
The __compiletime_strlen() macro expansion will shadow p_size and p_len
local variables. No callers currently use any of the shadowed names
for their "p" variable, so there are no code generation problems.
Add "__" prefixes to variable definitions __compiletime_strlen() to
avoid new W=2 warnings:
./include/linux/fortify-string.h: In function 'strnlen':
./include/linux/fortify-string.h:17:9: warning: declaration of 'p_size' shadows a previous local [-Wshadow]
17 | size_t p_size = __builtin_object_size(p, 1); \
| ^~~~~~
./include/linux/fortify-string.h:77:17: note: in expansion of macro '__compiletime_strlen'
77 | size_t p_len = __compiletime_strlen(p);
| ^~~~~~~~~~~~~~~~~~~~
./include/linux/fortify-string.h:76:9: note: shadowed declaration is here
76 | size_t p_size = __builtin_object_size(p, 1);
| ^~~~~~
Signed-off-by: Qian Cai <quic_qiancai@quicinc.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20211025210528.261643-1-quic_qiancai@quicinc.com
| -rw-r--r-- | include/linux/fortify-string.h | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index fdb0a74c9ca2..a6cd6815f249 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -10,18 +10,18 @@ void __read_overflow(void) __compiletime_error("detected read beyond size of obj void __read_overflow2(void) __compiletime_error("detected read beyond size of object (2nd parameter)"); void __write_overflow(void) __compiletime_error("detected write beyond size of object (1st parameter)"); -#define __compiletime_strlen(p) \ -({ \ - unsigned char *__p = (unsigned char *)(p); \ - size_t ret = (size_t)-1; \ - size_t p_size = __builtin_object_size(p, 1); \ - if (p_size != (size_t)-1) { \ - size_t p_len = p_size - 1; \ - if (__builtin_constant_p(__p[p_len]) && \ - __p[p_len] == '\0') \ - ret = __builtin_strlen(__p); \ - } \ - ret; \ +#define __compiletime_strlen(p) \ +({ \ + unsigned char *__p = (unsigned char *)(p); \ + size_t __ret = (size_t)-1; \ + size_t __p_size = __builtin_object_size(p, 1); \ + if (__p_size != (size_t)-1) { \ + size_t __p_len = __p_size - 1; \ + if (__builtin_constant_p(__p[__p_len]) && \ + __p[__p_len] == '\0') \ + __ret = __builtin_strlen(__p); \ + } \ + __ret; \ }) #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) |