[FFmpeg-devel] [PATCH 3/3] http: fix potentially dangerous whitespace skipping code

wm4 nfxjfg at googlemail.com
Thu Mar 8 05:53:57 EET 2018

If the string consists entirely of whitespace, this could in theory
continue to write '\0' before the start of the memory allocation. In
practice, it didn't really happen: the generic HTTP header parsing code
already skips leading whitespaces, so the string is either empty, or
consists a non-whitespace. (The generic code and the cookie code
actually have different ideas about what bytes are whitespace: the
former uses av_isspace(), the latter uses WHITESPACES. Fortunately,
av_isspace() is a super set of the http.c specific WHITESPACES, so
there's probably no case where the above assumption could have been
 libavformat/http.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/http.c b/libavformat/http.c
index 59f90ac603..983034f083 100644
--- a/libavformat/http.c
+++ b/libavformat/http.c
@@ -760,6 +760,8 @@ static int parse_set_cookie(const char *set_cookie, AVDictionary **dict)
     back = &cstr[strlen(cstr)-1];
     while (strchr(WHITESPACES, *back)) {
+        if (back == cstr)
+            break;

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