From bd2ce466bd00d2fcdbc5154754fc4711f3348a18 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Thu, 19 Dec 2019 19:37:34 -0500 Subject: [PATCH 1/7] e2fsck: abort if there is a corrupted directory block when rehashing In e2fsck pass 3a, when we are rehashing directories, at least in theory, all of the directories should have had corruptions with respect to directory entry structure fixed. However, it's possible (for example, if the user declined a fix) that we can reach this stage of processing with a corrupted directory entries. So check for that case and don't try to process a corrupted directory block so we don't run into trouble in mutate_name() if there is a zero-length file name. RHBZ: 1797731 Addresses: TALOS-2019-0973 Addresses: CVE-2019-5188 Signed-off-by: Theodore Ts'o --- e2fsck/rehash.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/e2fsck/rehash.c b/e2fsck/rehash.c index 3aafbb12..fbc4e558 100644 --- a/e2fsck/rehash.c +++ b/e2fsck/rehash.c @@ -129,6 +129,10 @@ static int fill_dir_block(ext2_filsys fs, dir_offset += rec_len; if (dirent->inode == 0) continue; + if ((dirent->name_len & 0xFF) == 0) { + fd->err = EXT2_ET_DIR_CORRUPTED; + return BLOCK_ABORT; + } if (!fd->compress && ((dirent->name_len&0xFF) == 1) && (dirent->name[0] == '.')) continue; @@ -367,6 +371,11 @@ static int duplicate_search_and_fix(e2fsck_t ctx, ext2_filsys fs, } memcpy(new_name, ent->dir->name, ent->dir->name_len & 0xFF); new_len = ent->dir->name_len; + if ((new_len & 0xFF) == 0) { + /* should never happen */ + ext2fs_unmark_valid(fs); + continue; + } mutate_name(new_name, &new_len); for (j=0; j < fd->num_array; j++) { if ((i==j) || -- 2.21.1