diff options
| author | Robert Doebbelin <robert@quobyte.com> | 2016-03-07 09:50:56 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-05-01 00:05:58 +0200 |
| commit | 9277aac3687ed46aaf14b8a0593319cdb6db675b (patch) | |
| tree | 425a4907c2ba4af75eeca3ff202f74c9278971ec /fs/fuse | |
| parent | db88024c8130eb7380ac5d8e4a39bb3fd1ad6eb1 (diff) | |
| download | linux-stable-9277aac3687ed46aaf14b8a0593319cdb6db675b.tar.gz linux-stable-9277aac3687ed46aaf14b8a0593319cdb6db675b.tar.bz2 linux-stable-9277aac3687ed46aaf14b8a0593319cdb6db675b.zip | |
fuse: do not use iocb after it may have been freed
commit 7cabc61e01a0a8b663bd2b4c982aa53048218734 upstream.
There's a race in fuse_direct_IO(), whereby is_sync_kiocb() is called on an
iocb that could have been freed if async io has already completed. The fix
in this case is simple and obvious: cache the result before starting io.
It was discovered by KASan:
kernel: ==================================================================
kernel: BUG: KASan: use after free in fuse_direct_IO+0xb1a/0xcc0 at addr ffff88036c414390
Signed-off-by: Robert Doebbelin <robert@quobyte.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: bcba24ccdc82 ("fuse: enable asynchronous processing direct IO")
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs/fuse')
| -rw-r--r-- | fs/fuse/file.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index e2a2c14a90ee..a6442041ab64 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -2876,6 +2876,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t i_size; size_t count = iov_iter_count(iter); struct fuse_io_priv *io; + bool is_sync = is_sync_kiocb(iocb); pos = offset; inode = file->f_mapping->host; @@ -2915,7 +2916,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, * to wait on real async I/O requests, so we must submit this request * synchronously. */ - if (!is_sync_kiocb(iocb) && (offset + count > i_size) && rw == WRITE) + if (!is_sync && (offset + count > i_size) && rw == WRITE) io->async = false; if (rw == WRITE) @@ -2927,7 +2928,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, fuse_aio_complete(io, ret < 0 ? ret : 0, -1); /* we have a non-extending, async request, so return */ - if (!is_sync_kiocb(iocb)) + if (!is_sync) return -EIOCBQUEUED; ret = wait_on_sync_kiocb(iocb); |