From 829680f96a7a7ff02d1543895ec0fb713309d5c0 Mon Sep 17 00:00:00 2001 From: Leo Izen Date: Tue, 15 Jul 2025 13:54:05 -0400 Subject: [PATCH] avcodec/jpegxl_parser: add sanity check for frame size MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If a frame size is absolutely massive, this can spin the parser as it attempts to decode a permuted TOC. We add a sanity check here for eight times the size of the image for an internal frame to prevent malicious bitstreams from slowing the parser down to a crawl. Signed-off-by: Leo Izen Reported-by: Kacper Michajłow --- libavcodec/jpegxl_parser.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/libavcodec/jpegxl_parser.c b/libavcodec/jpegxl_parser.c index 68404229a5..75acc53708 100644 --- a/libavcodec/jpegxl_parser.c +++ b/libavcodec/jpegxl_parser.c @@ -1315,6 +1315,13 @@ static int parse_frame_header(void *avctx, JXLParseContext *ctx, GetBitContext * if (get_bits1(gb)) { JXLEntropyDecoder dec; int64_t end, lehmer = 0; + /* parser sanity check to prevent TOC perm from spinning cpu */ + if (width > meta->coded_width * 8 || height > meta->coded_height * 8) { + av_log(avctx, AV_LOG_WARNING, "frame of size %" PRIu32 "x%" PRIu32 + " exceeds max size of %" PRIu32 "x%" PRIu32 ", aborting parser\n", + width, height, meta->coded_width * 8, meta->coded_height * 8); + return AVERROR_INVALIDDATA; + } ret = entropy_decoder_init(avctx, gb, &dec, 8); if (ret < 0) return ret; @@ -1331,7 +1338,7 @@ static int parse_frame_header(void *avctx, JXLParseContext *ctx, GetBitContext * lehmer = entropy_decoder_read_symbol(gb, &dec, toc_context(lehmer)); if (lehmer < 0 || get_bits_left(gb) < 0) { entropy_decoder_close(&dec); - return AVERROR_BUFFER_TOO_SMALL; + return lehmer < 0 ? lehmer : AVERROR_BUFFER_TOO_SMALL; } } entropy_decoder_close(&dec);