File e2fsck-abort-if-there-is-a-corrupted-directory-block.patch of Package e2fsprogs.13740

From 8dd73c149f418238f19791f9d666089ef9734dff Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
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 <tytso@mit.edu>
Acked-by: Jan Kara <jack@suse.cz>
---
 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) ||