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| author | Thomas Weißschuh <linux@weissschuh.net> | 2026-04-04 14:50:19 +0300 |
|---|---|---|
| committer | Thomas Weißschuh <linux@weissschuh.net> | 2026-04-06 20:46:52 +0300 |
| commit | 1e3c374e9fd5ef0bf1ebcb866505b1aad404959e (patch) | |
| tree | d6aa1b6831398bf62f34dd0d5d90ad419c6b0b5e /tools | |
| parent | 12496aad10c5671d66e160487326de942cd440ba (diff) | |
| download | linux-1e3c374e9fd5ef0bf1ebcb866505b1aad404959e.tar.xz | |
tools/nolibc: check for overflow in calloc() without divisions
On some architectures without native division instructions
the division can generate calls into libgcc/compiler-rt.
This library might not be available, so its use should be avoided.
Use the compiler builtin to check for overflows without needing a
division. The builtin has been available since GCC 3 and clang 3.8.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://patch.msgid.link/20260404-nolibc-asprintf-v2-1-17d2d0df9763@weissschuh.net
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/include/nolibc/stdlib.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h index 2113a8e7695d..1816c2368b68 100644 --- a/tools/include/nolibc/stdlib.h +++ b/tools/include/nolibc/stdlib.h @@ -145,9 +145,9 @@ void *malloc(size_t len) static __attribute__((unused)) void *calloc(size_t size, size_t nmemb) { - size_t x = size * nmemb; + size_t x; - if (__builtin_expect(size && ((x / size) != nmemb), 0)) { + if (__builtin_expect(__builtin_mul_overflow(size, nmemb, &x), 0)) { SET_ERRNO(ENOMEM); return NULL; } |