From 71f9bf7b08f2f7b632323719a4e69e94e0567a70 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 14 Feb 2021 23:51:45 -0500 Subject: [PATCH] libext2fs: fix crash when ext2fs_mmp_stop() is called before MMP is initialized 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 --- 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 c21ae27..023dccf 100644 --- a/lib/ext2fs/mmp.c +++ b/lib/ext2fs/mmp.c @@ -403,7 +403,8 @@ 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); -- 1.8.3.1