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| author | Rich Felker <dalias@aerifal.cx> | 2018-09-26 14:39:10 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2018-09-26 14:39:10 -0400 |
| commit | 4d0a82170a25464c39522d7190b9fe302045ddb2 (patch) | |
| tree | b3a469567ed3a995300c9751b824ef20b84f154d /src/string/strlcpy.c | |
| parent | 8cd738bbee3b4e60a99b71599c338bf444070f18 (diff) | |
| download | musl-4d0a82170a25464c39522d7190b9fe302045ddb2.tar.gz musl-4d0a82170a25464c39522d7190b9fe302045ddb2.tar.xz musl-4d0a82170a25464c39522d7190b9fe302045ddb2.zip | |
fix aliasing-based undefined behavior in string functions
use the GNU C may_alias attribute if available, and fallback to naive byte-by-byte loops if __GNUC__ is not defined. this patch has been written to minimize changes so that history remains reviewable; it does not attempt to bring the affected code into a more consistent or elegant form.
Diffstat (limited to 'src/string/strlcpy.c')
| -rw-r--r-- | src/string/strlcpy.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/string/strlcpy.c b/src/string/strlcpy.c index dcb22f6e..ffa0b0b0 100644 --- a/src/string/strlcpy.c +++ b/src/string/strlcpy.c @@ -12,9 +12,11 @@ size_t strlcpy(char *d, const char *s, size_t n) { char *d0 = d; size_t *wd; - const size_t *ws; if (!n--) goto finish; +#ifdef __GNUC__ + typedef size_t __attribute__((__may_alias__)) word; + const word *ws; if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) { for (; ((uintptr_t)s & ALIGN) && n && (*d=*s); n--, s++, d++); if (n && *s) { @@ -24,6 +26,7 @@ size_t strlcpy(char *d, const char *s, size_t n) d=(void *)wd; s=(const void *)ws; } } +#endif for (; n && (*d=*s); n--, s++, d++); *d = 0; finish: |