Re: [PATCH 2/2] xfs: make sure link path does not go away at access

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, 16 Nov 2021 at 04:01, Dave Chinner <david@xxxxxxxxxxxxx> wrote:

> I *think* that just zeroing the buffer means the race condition
> means the link resolves as either wholly intact, partially zeroed
> with trailing zeros in the length, wholly zeroed or zero length.
> Nothing will crash, the link string is always null terminated even
> if the length is wrong, and so nothing bad should happen as a result
> of zeroing the symlink buffer when it gets evicted from the VFS
> inode cache after unlink.

That's my thinking.  However, modifying the buffer while it is being
processed does seem pretty ugly, and I have to admit that I don't
understand why this needs to be done in either XFS or EXT4.

> The root cause is "allowing an inode to be reused without waiting
> for an RCU grace period to expire". This might seem pedantic, but
> "without waiting for an rcu grace period to expire" is the important
> part of the problem (i.e. the bug), not the "allowing an inode to be
> reused" bit.

Yes.

Thanks,
Miklos



[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [NTFS 3]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [NTFS 3]     [Samba]     [Device Mapper]     [CEPH Development]

  Powered by Linux