On 30.10.2022 11:02, Abdun Nihaal wrote:
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>
---
fs/ntfs3/frecord.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/ntfs3/frecord.c b/fs/ntfs3/frecord.c
index 70a80f9412f7..e55bbd209ef8 100644
--- a/fs/ntfs3/frecord.c
+++ b/fs/ntfs3/frecord.c
@@ -3243,6 +3243,9 @@ 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;
Thank you for your work, applied!
