From 8dd73c149f418238f19791f9d666089ef9734dff Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Thu, 19 Dec 2019 19:37:34 -0500 Subject: [PATCH] e2fsck: abort if there is a corrupted directory block when rehashing References: bsc#1160571 CVE-2019-5188 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. Addresses: TALOS-2019-0973 Addresses: CVE-2019-5188 Signed-off-by: Theodore Ts'o Acked-by: Jan Kara --- e2fsck/rehash.c | 9 +++++++++ 1 file changed, 9 insertions(+) Index: e2fsprogs-1.42.11/e2fsck/rehash.c =================================================================== --- e2fsprogs-1.42.11.orig/e2fsck/rehash.c +++ e2fsprogs-1.42.11/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; @@ -365,8 +369,13 @@ static int duplicate_search_and_fix(e2fs fixed++; continue; } - 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; + } + memcpy(new_name, ent->dir->name, new_len & 0xFF); mutate_name(new_name, &new_len); for (j=0; j < fd->num_array; j++) { if ((i==j) ||