diff options
| author | Robert Doebbelin <robert@quobyte.com> | 2016-03-07 09:50:56 +0100 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2017-06-17 15:50:39 +0200 |
| commit | 7e2cd0177d4e64717c323fa5df3f9a7d0eb59c68 (patch) | |
| tree | e5486e1af25be0a33f5febb75a185f4d8510056a | |
| parent | db70ea4aa161056ffb367913a6bce3ff03871ff3 (diff) | |
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")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -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 7149a96f3..ca1cf74cf 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -2726,6 +2726,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t i_size; size_t count = iov_length(iov, nr_segs); struct fuse_io_priv *io; + bool is_sync = is_sync_kiocb(iocb); pos = offset; inode = file->f_mapping->host; @@ -2761,7 +2762,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, * 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) @@ -2773,7 +2774,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, 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); |