Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1511824

Re: [PATCH] aio: fix a user triggered use after free (and fix freeze protection of aio writes)

From Christoph Hellwig <hch@lst.de>
Newsgroups linux.kernel
Subject Re: [PATCH] aio: fix a user triggered use after free (and fix freeze protection of aio writes)
Date 2016-10-29 17:30 +0200
Message-ID <sxDK1-7WB-17@gated-at.bofh.it> (permalink)
References <sxwyR-3dk-3@gated-at.bofh.it> <sxwyR-3dk-1@gated-at.bofh.it> <sxAVP-6bh-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

On Sat, Oct 29, 2016 at 01:24:51PM +0100, Al Viro wrote:
> How about taking this chunk (i.e. telling lockdep that we are not holding this
> thing) past the iter_op() call, where file_end_write() used to be?

We can't as that would not fix the use after free (at least for the lockdep
case - otherwise the call is a no-op).  Once iter_op returns aio_complete
might have dropped our reference to the file, and another thread might
have closed the fd so that the fput from aio_complete was the last one.

This is something that xfstests/323 can reproduce under the right conditions.

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH] aio: fix a user triggered use after free (and fix freeze protection of aio writes) Christoph Hellwig <hch@lst.de> - 2016-10-29 09:50 +0200
  Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Al Viro <viro@ZenIV.linux.org.uk> - 2016-10-29 14:30 +0200
    Re: [PATCH] aio: fix a user triggered use after free (and fix         freeze protection of aio writes) Christoph Hellwig <hch@lst.de> - 2016-10-29 17:30 +0200
      Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Al Viro <viro@ZenIV.linux.org.uk> - 2016-10-29 18:20 +0200
        Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Al Viro <viro@ZenIV.linux.org.uk> - 2016-10-29 18:40 +0200
        Re: [PATCH] aio: fix a user triggered use after free (and fix         freeze protection of aio writes) Christoph Hellwig <hch@lst.de> - 2016-10-30 07:40 +0100
      Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-29 19:50 +0200
        Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Al Viro <viro@ZenIV.linux.org.uk> - 2016-10-29 21:00 +0200
          Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-29 21:10 +0200
            Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Al Viro <viro@ZenIV.linux.org.uk> - 2016-10-29 21:20 +0200
              Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-29 22:10 +0200
                Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Jan Kara <jack@suse.cz> - 2016-10-30 10:50 +0100
                Re: [PATCH] aio: fix a user triggered use after free (and fix freeze  protection of aio writes) Jan Kara <jack@suse.cz> - 2016-10-30 12:00 +0100
                Re: [PATCH] aio: fix a user triggered use after free (and fix         freeze protection of aio writes) Christoph Hellwig <hch@lst.de> - 2016-10-30 17:00 +0100
        Re: [PATCH] aio: fix a user triggered use after free (and fix         freeze protection of aio writes) Christoph Hellwig <hch@lst.de> - 2016-10-30 07:40 +0100

csiph-web