diff options
| author | Robert Doebbelin <robert@quobyte.com> | 2016-03-07 09:50:56 +0100 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2017-01-27 17:14:58 +0100 |
| commit | 77eed17655f6176a74b70005a337127838057235 (patch) | |
| tree | d71c1c1dc286a28b8a82f643e6dec305fff145f0 | |
| parent | 969541196ff043df0bde0c4beae9d83185ea3d81 (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: Jiri Slaby <jslaby@suse.cz>
| -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 8ef52e12cd57..f6314cd3e3b0 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -2393,6 +2393,7 @@ 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; @@ -2428,7 +2429,7 @@ 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) @@ -2440,7 +2441,7 @@ 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); |