av_get_token() allocates an output buffer with the same size as the input. Generally, this is harmless, but when the input string is large and consists of many small tokens, calling av_get_token() repeatedly to extract all tokens will significantly amplify memory allocations.
To fix this, after obtaining the return value, simply realloc the buffer to the actual size needed for output string. Fixes OOM when parsing filter graph string. Fixes OSS-Fuzz: 394983446 Signed-off-by: Kacper Michajłow <[email protected]> --- libavutil/avstring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libavutil/avstring.c b/libavutil/avstring.c index 875eb691db..b4266aefe5 100644 --- a/libavutil/avstring.c +++ b/libavutil/avstring.c @@ -142,7 +142,7 @@ end: char *av_get_token(const char **buf, const char *term) { - char *out = av_malloc(strlen(*buf) + 1); + char *out = av_realloc(NULL, strlen(*buf) + 1); char *ret = out, *end = out; const char *p = *buf; if (!out) @@ -172,7 +172,7 @@ char *av_get_token(const char **buf, const char *term) *buf = p; - return ret; + return av_realloc(ret, out - ret + 2); } char *av_strtok(char *s, const char *delim, char **saveptr) -- 2.47.2 _______________________________________________ ffmpeg-devel mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
