6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jens Axboe axboe@kernel.dk
commit 72bd80252feeb3bef8724230ee15d9f7ab541c6e upstream.
If we use IORING_OP_RECV with provided buffers and pass in '0' as the length of the request, the length is retrieved from the selected buffer. If MSG_WAITALL is also set and we get a short receive, then we may hit the retry path which decrements sr->len and increments the buffer for a retry. However, the length is still zero at this point, which means that sr->len now becomes huge and import_ubuf() will cap it to MAX_RW_COUNT and subsequently return -EFAULT for the range as a whole.
Fix this by always assigning sr->len once the buffer has been selected.
Cc: stable@vger.kernel.org Fixes: 7ba89d2af17a ("io_uring: ensure recv and recvmsg handle MSG_WAITALL correctly") Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- io_uring/net.c | 1 + 1 file changed, 1 insertion(+)
--- a/io_uring/net.c +++ b/io_uring/net.c @@ -875,6 +875,7 @@ retry_multishot: if (!buf) return -ENOBUFS; sr->buf = buf; + sr->len = len; }
ret = import_single_range(ITER_DEST, sr->buf, len, &iov, &msg.msg_iter);