From 1527ac4626b4bf1bcc46203481003a7f33e2aca5 Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Tue, 21 Jun 2022 14:43:30 +0100 Subject: [PATCH] Fix invalid pointer dereference in wcscpy_chk The src pointer is const and points to a different object, so accessing dest via src is invalid. Reviewed-by: Florian Weimer --- debug/wcscpy_chk.c | 34 +++++++--------------------------- 1 file changed, 7 insertions(+), 27 deletions(-) diff --git a/debug/wcscpy_chk.c b/debug/wcscpy_chk.c index dfe475da..8115b00e 100644 --- a/debug/wcscpy_chk.c +++ b/debug/wcscpy_chk.c @@ -25,36 +25,16 @@ wchar_t * __wcscpy_chk (wchar_t *dest, const wchar_t *src, size_t n) { wint_t c; - wchar_t *wcp; + wchar_t *wcp = dest; - if (__alignof__ (wchar_t) >= sizeof (wchar_t)) + do { - const ptrdiff_t off = dest - src - 1; - - wcp = (wchar_t *) src; - - do - { - if (__glibc_unlikely (n-- == 0)) - __chk_fail (); - c = *wcp++; - wcp[off] = c; - } - while (c != L'\0'); - } - else - { - wcp = dest; - - do - { - if (__glibc_unlikely (n-- == 0)) - __chk_fail (); - c = *src++; - *wcp++ = c; - } - while (c != L'\0'); + if (__glibc_unlikely (n-- == 0)) + __chk_fail (); + c = *src++; + *wcp++ = c; } + while (c != L'\0'); return dest; } -- 2.27.0