From f1bc162cc272e01631e8f6d890fae71e1cb96e03 Mon Sep 17 00:00:00 2001 From: Nicolas Iooss Date: Fri, 30 Apr 2021 21:37:02 +0200 Subject: [PATCH] libselinux: silence -Wstringop-overflow warning from gcc 10.3.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When building libselinux on Fedora 33 with gcc 10.3.1, the compiler reports: label_file.c: In function ‘lookup_all.isra’: label_file.c:940:4: error: ‘strncpy’ specified bound depends on the length of the source argument [-Werror=stringop-overflow=] 940 | strncpy(clean_key, key, len - 1); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ label_file.c:927:8: note: length computed here 927 | len = strlen(key); | ^~~~~~~~~~~ cc1: all warnings being treated as errors As clean_key is the result of malloc(len), there is no issue here. But using strncpy can be considered as strange, because the size of the string is already known and the NUL terminator is always added later, in function ‘lookup_all.isra. Replace strncpy with memcpy to silence this gcc false-positive warning. Signed-off-by: Nicolas Iooss Acked-by: Petr Lautrbach --- libselinux/src/label_file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c index 726394ca..cfce23e0 100644 --- a/libselinux/src/label_file.c +++ b/libselinux/src/label_file.c @@ -909,7 +909,7 @@ static const struct spec **lookup_all(struct selabel_handle *rec, if (!clean_key) goto finish; - strncpy(clean_key, key, len - 1); + memcpy(clean_key, key, len - 1); } clean_key[len - 1] = '\0';