From: Maurizio Lombardi <mlombard@redhat.com>
Date: Fri, 22 Dec 2023 16:17:48 +0100
Subject: nvmet-tcp: Fix a kernel panic when host sends an invalid H2C PDU
 length
Patch-mainline: v6.8-rc1
Git-commit: efa56305908ba20de2104f1b8508c6a7401833be
References: bsc#1217987 bsc#1217988 bsc#1217989 CVE-2023-6535 CVE-2023-6536 CVE-2023-6356 CVE-2023-52454 bsc#1220320

If the host sends an H2CData command with an invalid DATAL,
the kernel may crash in nvmet_tcp_build_pdu_iovec().

Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000000
lr : nvmet_tcp_io_work+0x6ac/0x718 [nvmet_tcp]
Call trace:
  process_one_work+0x174/0x3c8
  worker_thread+0x2d0/0x3e8
  kthread+0x104/0x110

Fix the bug by raising a fatal error if DATAL isn't coherent
with the packet size.
Also, the PDU length should never exceed the MAXH2CDATA parameter which
has been communicated to the host in nvmet_tcp_handle_icreq().

Fixes: 872d26a391da ("nvmet-tcp: add NVMe over TCP target driver")
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/target/tcp.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -18,6 +18,7 @@
 #include "nvmet.h"
 
 #define NVMET_TCP_DEF_INLINE_DATA_SIZE	(4 * PAGE_SIZE)
+#define NVMET_TCP_MAXH2CDATA		0x400000 /* 16M arbitrary limit */
 
 /* Define the socket priority to use for connections were it is desirable
  * that the NIC consider performing optimized packet processing or filtering.
@@ -867,7 +868,7 @@ static int nvmet_tcp_handle_icreq(struct
 	icresp->hdr.pdo = 0;
 	icresp->hdr.plen = cpu_to_le32(icresp->hdr.hlen);
 	icresp->pfv = cpu_to_le16(NVME_TCP_PFV_1_0);
-	icresp->maxdata = cpu_to_le32(0x400000); /* 16M arbitrary limit */
+	icresp->maxdata = cpu_to_le32(NVMET_TCP_MAXH2CDATA);
 	icresp->cpda = 0;
 	if (queue->hdr_digest)
 		icresp->digest |= NVME_TCP_HDR_DIGEST_ENABLE;
@@ -913,6 +914,7 @@ static int nvmet_tcp_handle_h2c_data_pdu
 {
 	struct nvme_tcp_data_pdu *data = &queue->pdu.data;
 	struct nvmet_tcp_cmd *cmd;
+	unsigned int plen;
 
 	if (likely(queue->nr_cmds)) {
 		if (unlikely(data->ttag >= queue->nr_cmds)) {
@@ -936,7 +938,16 @@ static int nvmet_tcp_handle_h2c_data_pdu
 		return -EPROTO;
 	}
 
+	plen = le32_to_cpu(data->hdr.plen);
 	cmd->pdu_len = le32_to_cpu(data->data_length);
+	if (unlikely(cmd->pdu_len != (plen - sizeof(*data)) ||
+		     cmd->pdu_len == 0 ||
+		     cmd->pdu_len > NVMET_TCP_MAXH2CDATA)) {
+		pr_err("H2CData PDU len %u is invalid\n", cmd->pdu_len);
+		/* FIXME: use proper transport errors */
+		nvmet_tcp_fatal_error(queue);
+		return -EPROTO;
+	}
 	cmd->pdu_recv = 0;
 	nvmet_tcp_map_pdu_iovec(cmd);
 	queue->cmd = cmd;