[SRU][Focal][PATCH 2/2] nvmet-tcp: Fix a possible UAF in queue intialization setup

[Yuxuan Luo]

From: Sagi Grimberg <sagi at grimberg.me>

>From Alon:
"Due to a logical bug in the NVMe-oF/TCP subsystem in the Linux kernel,
a malicious user can cause a UAF and a double free, which may lead to
RCE (may also lead to an LPE in case the attacker already has local
privileges)."

Hence, when a queue initialization fails after the ahash requests are
allocated, it is guaranteed that the queue removal async work will be
called, hence leave the deallocation to the queue removal.

Also, be extra careful not to continue processing the socket, so set
queue rcv_state to NVMET_TCP_RECV_ERR upon a socket error.

Cc: stable at vger.kernel.org
Reported-by: Alon Zahavi <zahavi.alon at gmail.com>
Tested-by: Alon Zahavi <zahavi.alon at gmail.com>
Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
Reviewed-by: Christoph Hellwig <hch at lst.de>
Reviewed-by: Chaitanya Kulkarni <kch at nvidia.com>
Signed-off-by: Keith Busch <kbusch at kernel.org>
(cherry picked from commit d920abd1e7c4884f9ecd0749d1921b7ab19ddfbd)
CVE-2023-5178
Signed-off-by: Yuxuan Luo <yuxuan.luo at canonical.com>
---
 drivers/nvme/target/tcp.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index e63a50e22e5a0..e8c7135c4c11b 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -323,6 +323,7 @@ static void nvmet_tcp_fatal_error(struct nvmet_tcp_queue *queue)
 
 static void nvmet_tcp_socket_error(struct nvmet_tcp_queue *queue, int status)
 {
+	queue->rcv_state = NVMET_TCP_RECV_ERR;
 	if (status == -EPIPE || status == -ECONNRESET)
 		kernel_sock_shutdown(queue->sock, SHUT_RDWR);
 	else
@@ -828,15 +829,11 @@ static int nvmet_tcp_handle_icreq(struct nvmet_tcp_queue *queue)
 	iov.iov_len = sizeof(*icresp);
 	ret = kernel_sendmsg(queue->sock, &msg, &iov, 1, iov.iov_len);
 	if (ret < 0)
-		goto free_crypto;
+		return ret; /* queue removal will cleanup */
 
 	queue->state = NVMET_TCP_Q_LIVE;
 	nvmet_prepare_receive_pdu(queue);
 	return 0;
-free_crypto:
-	if (queue->hdr_digest || queue->data_digest)
-		nvmet_tcp_free_crypto(queue);
-	return ret;
 }
 
 static void nvmet_tcp_handle_req_failure(struct nvmet_tcp_queue *queue,
-- 
2.34.1