diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2019-11-24 11:58:24 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-11-25 19:56:11 -0700 |
| commit | 311ae9e159d81a1ec1cf645daf40b39ae5a0bd84 (patch) | |
| tree | 08f3dbc913f0459274073109bd6c47d83cdac82b /fs/io_uring.c | |
| parent | f8e85cf255ad57d65eeb9a9d0e59e3dec55bdd9e (diff) | |
io_uring: fix dead-hung for non-iter fixed rw
Read/write requests to devices without implemented read/write_iter
using fixed buffers can cause general protection fault, which totally
hangs a machine.
io_import_fixed() initialises iov_iter with bvec, but loop_rw_iter()
accesses it as iovec, dereferencing random address.
kmap() page by page in this case
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 02254929231b..fc832164bbb8 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1622,9 +1622,19 @@ static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb, return -EAGAIN; while (iov_iter_count(iter)) { - struct iovec iovec = iov_iter_iovec(iter); + struct iovec iovec; ssize_t nr; + if (!iov_iter_is_bvec(iter)) { + iovec = iov_iter_iovec(iter); + } else { + /* fixed buffers import bvec */ + iovec.iov_base = kmap(iter->bvec->bv_page) + + iter->iov_offset; + iovec.iov_len = min(iter->count, + iter->bvec->bv_len - iter->iov_offset); + } + if (rw == READ) { nr = file->f_op->read(file, iovec.iov_base, iovec.iov_len, &kiocb->ki_pos); @@ -1633,6 +1643,9 @@ static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb, iovec.iov_len, &kiocb->ki_pos); } + if (iov_iter_is_bvec(iter)) + kunmap(iter->bvec->bv_page); + if (nr < 0) { if (!ret) ret = nr; |