From: Abdun Nihaal <abdun.nihaal@xxxxxxxxx> [ Upstream commit 8dae4f6341e335a09575be60b4fdf697c732a470 ] Syzbot reports a NULL dereference in ni_write_inode. When creating a new inode, if allocation fails in mi_init function (called in mi_format_new function), mi->mrec is set to NULL. In the error path of this inode creation, mi->mrec is later dereferenced in ni_write_inode. Add a NULL check to prevent NULL dereference. Link: https://syzkaller.appspot.com/bug?extid=f45957555ed4a808cc7a Reported-and-tested-by: syzbot+f45957555ed4a808cc7a@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Abdun Nihaal <abdun.nihaal@xxxxxxxxx> Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ntfs3/frecord.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ntfs3/frecord.c b/fs/ntfs3/frecord.c index cdeb0b51f0ba8..95556515ded3d 100644 --- a/fs/ntfs3/frecord.c +++ b/fs/ntfs3/frecord.c @@ -3189,6 +3189,9 @@ int ni_write_inode(struct inode *inode, int sync, const char *hint) return 0; } + if (!ni->mi.mrec) + goto out; + if (is_rec_inuse(ni->mi.mrec) && !(sbi->flags & NTFS_FLAGS_LOG_REPLAYING) && inode->i_nlink) { bool modified = false; -- 2.39.2
