Date: Fri, 3 Oct 2025 17:48:29 GMT
From: Robert Clausecker <fuz@FreeBSD.org>
To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Subject: git: 7233893e9496 - main - lib{c,openbsd}: use ckd_mul() for overflow checking in re(c)allocarray
Message-ID: <202510031748.593HmTBK060773@gitrepo.freebsd.org>
next in thread | raw e-mail | index | archive | help
The branch main has been updated by fuz: URL: https://cgit.FreeBSD.org/src/commit/?id=7233893e949689d378d38c11651e68321deed12c commit 7233893e949689d378d38c11651e68321deed12c Author: Robert Clausecker <fuz@FreeBSD.org> AuthorDate: 2025-10-02 13:26:46 +0000 Commit: Robert Clausecker <fuz@FreeBSD.org> CommitDate: 2025-10-03 17:45:54 +0000 lib{c,openbsd}: use ckd_mul() for overflow checking in re(c)allocarray Summary: This makes the code easier to understand and slightly faster, but requires C23. calloc() would benefit, too, but I didn't want to touch the imported jemalloc code base. Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D52854 --- lib/libc/stdlib/reallocarray.c | 14 +++++--------- lib/libopenbsd/recallocarray.c | 15 +++------------ 2 files changed, 8 insertions(+), 21 deletions(-) diff --git a/lib/libc/stdlib/reallocarray.c b/lib/libc/stdlib/reallocarray.c index 0868804486cc..3632734c84de 100644 --- a/lib/libc/stdlib/reallocarray.c +++ b/lib/libc/stdlib/reallocarray.c @@ -17,23 +17,19 @@ #include <sys/types.h> #include <errno.h> +#include <stdckdint.h> #include <stdint.h> #include <stdlib.h> -/* - * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX - * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW - */ -#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4)) - void * reallocarray(void *optr, size_t nmemb, size_t size) { + size_t nbytes; - if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && - nmemb > 0 && SIZE_MAX / nmemb < size) { + if (ckd_mul(&nbytes, nmemb, size)) { errno = ENOMEM; return (NULL); } - return (realloc(optr, size * nmemb)); + + return (realloc(optr, nbytes)); } diff --git a/lib/libopenbsd/recallocarray.c b/lib/libopenbsd/recallocarray.c index 11e1fda744c7..cbf1fb2470cf 100644 --- a/lib/libopenbsd/recallocarray.c +++ b/lib/libopenbsd/recallocarray.c @@ -16,17 +16,12 @@ */ #include <errno.h> +#include <stdckdint.h> #include <stdlib.h> #include <stdint.h> #include <string.h> #include <unistd.h> -/* - * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX - * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW - */ -#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4)) - void *recallocarray(void *, size_t, size_t, size_t); void * @@ -38,19 +33,15 @@ recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size) if (ptr == NULL) return calloc(newnmemb, size); - if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && - newnmemb > 0 && SIZE_MAX / newnmemb < size) { + if (ckd_mul(&newsize, newnmemb, size)) { errno = ENOMEM; return NULL; } - newsize = newnmemb * size; - if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && - oldnmemb > 0 && SIZE_MAX / oldnmemb < size) { + if (ckd_mul(&oldsize, oldnmemb, size)) { errno = EINVAL; return NULL; } - oldsize = oldnmemb * size; /* * Don't bother too much if we're shrinking just a bit,
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?202510031748.593HmTBK060773>