Messages in this thread Patch in this message | | | Date | Thu, 26 May 2022 13:22:27 +0300 | Subject | Re: [PATCH] fs/ntfs3: fix null pointer dereference in d_flags_for_inode | From | Almaz Alexandrovich <> |
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Hello.
Thank you for reporting this bug. The bug happens because we don't initialize i_op for records in $Extend. We tested patch on our side, let me know if patch helps you too.
fs/ntfs3: Fix missing i_op in ntfs_read_mft
There is null pointer dereference because i_op == NULL. The bug happens because we don't initialize i_op for records in $Extend. Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
Reported-by: Liangbin Lian <jjm2473@gmail.com> Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c index 879952254071..b2cc1191be69 100644 --- a/fs/ntfs3/inode.c +++ b/fs/ntfs3/inode.c @@ -430,6 +430,7 @@ static struct inode *ntfs_read_mft(struct inode *inode, } else if (fname && fname->home.low == cpu_to_le32(MFT_REC_EXTEND) && fname->home.seq == cpu_to_le16(MFT_REC_EXTEND)) { /* Records in $Extend are not a files or general directories. */ + inode->i_op = &ntfs_file_inode_operations; } else { err = -EINVAL; goto out;
On 5/6/22 06:46, Liangbin Lian wrote: > ntfs_read_mft may return inode with null i_op, cause null pointer dereference in d_flags_for_inode (inode->i_op->get_link). > Reproduce: > - sudo mount -t ntfs3 -o loop ntfs.img ntfs > - ls ntfs/'$Extend/$Quota' > > The call trace is shown below (striped): > BUG: kernel NULL pointer dereference, address: 0000000000000008 > CPU: 0 PID: 577 Comm: ls Tainted: G OE 5.16.0-0.bpo.4-amd64 #1 Debian 5.16.12-1~bpo11+1 > RIP: 0010:d_flags_for_inode+0x65/0x90 > Call Trace: > ntfs_lookup > +--- dir_search_u > | +--- ntfs_iget5 > | +--- ntfs_read_mft > +--- d_splice_alias > +--- __d_add > +--- d_flags_for_inode > > Signed-off-by: Liangbin Lian <jjm2473@gmail.com> > --- > fs/ntfs3/inode.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c > index 9eab11e3b..b68d26fa8 100644 > --- a/fs/ntfs3/inode.c > +++ b/fs/ntfs3/inode.c > @@ -45,7 +45,6 @@ static struct inode *ntfs_read_mft(struct inode *inode, > struct MFT_REC *rec; > struct runs_tree *run; > > - inode->i_op = NULL; > /* Setup 'uid' and 'gid' */ > inode->i_uid = sbi->options->fs_uid; > inode->i_gid = sbi->options->fs_gid;
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