From d497224dfbfdc1313136488cd7fb196885d40dfb Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 6 Jun 2022 12:03:36 -0400 Subject: [PATCH] libext2fs: add check for too-short directory blocks MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit If there is an inline data directory which is smaller than 8 bytes (which should never happen but for corrupted or fuzzed file systems), ext2fs_process_dir_block() will now abort EXT2_ET_DIR_CORRUPTED to avoid an out-of-bounds read. Reported-by: Nils Bars Reported-by: Moritz Schlögel Reported-by: Nico Schiller Signed-off-by: Theodore Ts'o --- lib/ext2fs/dir_iterate.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/ext2fs/dir_iterate.c b/lib/ext2fs/dir_iterate.c index b2b7769..7798a48 100644 --- a/lib/ext2fs/dir_iterate.c +++ b/lib/ext2fs/dir_iterate.c @@ -221,6 +221,10 @@ int ext2fs_process_dir_block(ext2_filsys fs, if (ext2fs_has_feature_metadata_csum(fs->super)) csum_size = sizeof(struct ext2_dir_entry_tail); + if (buflen < 8) { + ctx->errcode = EXT2_ET_DIR_CORRUPTED; + return BLOCK_ABORT; + } while (offset < buflen - 8) { dirent = (struct ext2_dir_entry *) (ctx->buf + offset); if (ext2fs_get_rec_len(fs, dirent, &rec_len)) -- 1.8.3.1