From df34e45c71cff889927a412c6296d02866cdc5cc Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Sun, 14 Feb 2021 23:51:45 -0500
Subject: [PATCH 20/46] libext2fs: fix crash when ext2fs_mmp_stop() is called
before MMP is initialized
Content-Type: text/plain
The fatal_error() function in e2fsck can call ext2fs_mmp_stop() on a
file system where MMP hasn't yet been initialized. When that happens,
instead of crashing, have ext2fs_mmp_stop() return success, since mmp
doesn't need to be stopped if it hasn't even been initialized yet.
Addresses-Debian-Bug: #696609
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
---
lib/ext2fs/mmp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/lib/ext2fs/mmp.c b/lib/ext2fs/mmp.c
index 973b9ecd..eddc66a7 100644
--- a/lib/ext2fs/mmp.c
+++ b/lib/ext2fs/mmp.c
@@ -401,7 +401,8 @@ errcode_t ext2fs_mmp_stop(ext2_filsys fs)
errcode_t retval = 0;
if (!ext2fs_has_feature_mmp(fs->super) ||
- !(fs->flags & EXT2_FLAG_RW) || (fs->flags & EXT2_FLAG_SKIP_MMP))
+ !(fs->flags & EXT2_FLAG_RW) || (fs->flags & EXT2_FLAG_SKIP_MMP) ||
+ (fs->mmp_buf == NULL) || (fs->mmp_cmp == NULL))
goto mmp_error;
retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, fs->mmp_buf);
--
2.35.1