* [Qemu-devel] [PATCH] virtiofsd: fix req use-after-free in lo_flush()
@ 2019-08-01 16:32 Stefan Hajnoczi
2019-08-01 16:36 ` Dr. David Alan Gilbert
0 siblings, 1 reply; 2+ messages in thread
From: Stefan Hajnoczi @ 2019-08-01 16:32 UTC (permalink / raw)
To: qemu-devel, virtio-fs; +Cc: Dr. David Alan Gilbert, Stefan Hajnoczi
Isn't it funny that a commit trying to fix use-after-free introduced its
own use-after-free?
fuse_reply_err() frees the request so we cannot call lo_data(req)
afterwards.
Fixes: a5081fc6fc3603671383616127b3a5e169cf64ed
("virtiofsd: introduce inode refcount to prevent use-after-free")
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
contrib/virtiofsd/passthrough_ll.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthrough_ll.c
index ee8627446a..a81c01d0d1 100644
--- a/contrib/virtiofsd/passthrough_ll.c
+++ b/contrib/virtiofsd/passthrough_ll.c
@@ -1969,9 +1969,8 @@ static void lo_flush(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
pthread_mutex_unlock(&inode->plock_mutex);
res = close(dup(lo_fi_fd(req, fi)));
- fuse_reply_err(req, res == -1 ? errno : 0);
-
lo_inode_put(lo_data(req), &inode);
+ fuse_reply_err(req, res == -1 ? errno : 0);
}
static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync,
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [Qemu-devel] [PATCH] virtiofsd: fix req use-after-free in lo_flush()
2019-08-01 16:32 [Qemu-devel] [PATCH] virtiofsd: fix req use-after-free in lo_flush() Stefan Hajnoczi
@ 2019-08-01 16:36 ` Dr. David Alan Gilbert
0 siblings, 0 replies; 2+ messages in thread
From: Dr. David Alan Gilbert @ 2019-08-01 16:36 UTC (permalink / raw)
To: Stefan Hajnoczi; +Cc: virtio-fs, qemu-devel
* Stefan Hajnoczi (stefanha@redhat.com) wrote:
> Isn't it funny that a commit trying to fix use-after-free introduced its
> own use-after-free?
>
> fuse_reply_err() frees the request so we cannot call lo_data(req)
> afterwards.
>
> Fixes: a5081fc6fc3603671383616127b3a5e169cf64ed
> ("virtiofsd: introduce inode refcount to prevent use-after-free")
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Squashed into the top.
Dave
> ---
> contrib/virtiofsd/passthrough_ll.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthrough_ll.c
> index ee8627446a..a81c01d0d1 100644
> --- a/contrib/virtiofsd/passthrough_ll.c
> +++ b/contrib/virtiofsd/passthrough_ll.c
> @@ -1969,9 +1969,8 @@ static void lo_flush(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
> pthread_mutex_unlock(&inode->plock_mutex);
>
> res = close(dup(lo_fi_fd(req, fi)));
> - fuse_reply_err(req, res == -1 ? errno : 0);
> -
> lo_inode_put(lo_data(req), &inode);
> + fuse_reply_err(req, res == -1 ? errno : 0);
> }
>
> static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync,
> --
> 2.21.0
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2019-08-01 16:39 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2019-08-01 16:32 [Qemu-devel] [PATCH] virtiofsd: fix req use-after-free in lo_flush() Stefan Hajnoczi
2019-08-01 16:36 ` Dr. David Alan Gilbert
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).