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gh-126024: fix UBSan failure in unicodeobject.c:find_first_nonascii (GH-127566)

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Bénédikt Tran
2024-12-06 15:31:30 +01:00
committed by GitHub
parent 77a61c0465
commit 36c6178d37
1 changed files with 3 additions and 6 deletions
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9
Objects/unicodeobject.c
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@@ -5083,12 +5083,9 @@ find_first_nonascii(const unsigned char *start, const unsigned char *end)
const unsigned char *p2 = _Py_ALIGN_UP(p, SIZEOF_SIZE_T);
#if PY_LITTLE_ENDIAN && HAVE_CTZ
if (p < p2) {
#if defined(_M_AMD64) || defined(_M_IX86) || defined(__x86_64__) || defined(__i386__)
// x86 and amd64 are little endian and can load unaligned memory.
size_t u = *(const size_t*)p & ASCII_CHAR_MASK;
#else
size_t u = load_unaligned(p, p2 - p) & ASCII_CHAR_MASK;
#endif
size_t u;
memcpy(&u, p, sizeof(size_t));
u &= ASCII_CHAR_MASK;
if (u) {
return (ctz(u) - 7) / 8;
}