From 81b26f8f2891f1a63d5dbf7c2d4209b8325062b6 Mon Sep 17 00:00:00 2001 From: Phillip Wood Date: Mon, 20 Mar 2023 16:10:01 +0000 Subject: wildmatch: avoid undefined behavior The code changed in this commit is designed to check if the pattern starts with "**/" or contains "/**/" (see 3a078dec33 (wildmatch: fix "**" special case, 2013-01-01)). Unfortunately when the pattern begins with "**/" `prev_p = p - 2` is evaluated when `p` points to the second "*" and so the subtraction is undefined according to section 6.5.6 of the C standard because the result does not point within the same object as `p`. Fix this by avoiding the subtraction unless it is well defined. Signed-off-by: Phillip Wood Signed-off-by: Junio C Hamano --- wildmatch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'wildmatch.c') diff --git a/wildmatch.c b/wildmatch.c index 06861bd8bc..694d2f8e40 100644 --- a/wildmatch.c +++ b/wildmatch.c @@ -83,12 +83,12 @@ static int dowild(const uchar *p, const uchar *text, unsigned int flags) continue; case '*': if (*++p == '*') { - const uchar *prev_p = p - 2; + const uchar *prev_p = p; while (*++p == '*') {} if (!(flags & WM_PATHNAME)) /* without WM_PATHNAME, '*' == '**' */ match_slash = 1; - else if ((prev_p < pattern || *prev_p == '/') && + else if ((prev_p - pattern < 2 || *(prev_p - 2) == '/') && (*p == '\0' || *p == '/' || (p[0] == '\\' && p[1] == '/'))) { /* -- cgit v1.2.3