From 0ceb7a9230d662633afe6b748bdbd4ba3d3c6328 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 1 Feb 2024 06:42:36 -0700 Subject: [PATCH] io_uring/net: fix sr->len for IORING_OP_RECV with MSG_WAITALL and buffers 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 Signed-off-by: Greg Kroah-Hartman --- io_uring/net.c | 1 + 1 file changed, 1 insertion(+) diff --git a/io_uring/net.c b/io_uring/net.c index 75d494d..fb265c9d 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -902,6 +902,7 @@ retry_multishot: if (!buf) return -ENOBUFS; sr->buf = buf; + sr->len = len; } ret = import_ubuf(ITER_DEST, sr->buf, len, &msg.msg_iter); -- 2.7.4