Avoid stat() on NULL path in curl_download_internal()

stat()'s behaviour is undefined if the first argument is NULL and might
be prone to segfault. Add an additional check to skip the stat()
invocation if no destfile is used.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>
Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
index fd5c9289..357544bb 100644
--- a/lib/libalpm/dload.c
+++ b/lib/libalpm/dload.c
@@ -261,7 +261,7 @@ static int curl_download_internal(struct dload_payload *payload,
 		curl_easy_setopt(handle->curl, CURLOPT_USERAGENT, useragent);
 	}
 
-	if(!payload->allow_resume && !payload->force && stat(destfile, &st) == 0) {
+	if(!payload->allow_resume && !payload->force && destfile && stat(destfile, &st) == 0) {
 		/* start from scratch, but only download if our local is out of date. */
 		curl_easy_setopt(handle->curl, CURLOPT_TIMECONDITION, CURL_TIMECOND_IFMODSINCE);
 		curl_easy_setopt(handle->curl, CURLOPT_TIMEVALUE, (long)st.st_mtime);