From f33faa5b9bfb288f83db034fa1f8719ab8a994c6 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sun, 23 Aug 2020 00:31:17 +0200 Subject: avfilter/graphparser: Don't set pointer to one beyond '\0' of string This happened in parse_link_name() if there was a '[' without matching ']'. While this is not undefined behaviour (pointer arithmetic one beyond the end of an array works fine as long as there are no accesses), it is potentially dangerous. It currently isn't (all callers of parse_link_name() treat this as an error and don't access the string any more), but making sure that this will never cause trouble in the future seems nevertheless worthwhile. Reviewed-by: Nicolas George Signed-off-by: Andreas Rheinhardt --- libavfilter/graphparser.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/libavfilter/graphparser.c b/libavfilter/graphparser.c index dfb94788e1..e96b20418e 100644 --- a/libavfilter/graphparser.c +++ b/libavfilter/graphparser.c @@ -63,7 +63,7 @@ static char *parse_link_name(const char **buf, void *log_ctx) name = av_get_token(buf, "]"); if (!name) - goto fail; + return NULL; if (!name[0]) { av_log(log_ctx, AV_LOG_ERROR, @@ -71,12 +71,14 @@ static char *parse_link_name(const char **buf, void *log_ctx) goto fail; } - if (*(*buf)++ != ']') { + if (**buf != ']') { av_log(log_ctx, AV_LOG_ERROR, "Mismatched '[' found in the following: \"%s\".\n", start); fail: av_freep(&name); + return NULL; } + (*buf)++; return name; } -- cgit v1.2.3