[PATCH 5.15.y 3/5] nvmet-tcp: fix regression in data_digest calculation

[Sasha Levin <sashal@kernel.org>]

From: Sagi Grimberg <sagi@grimberg.me>

[ Upstream commit ed0691cf55140ce0f3fb100225645d902cce904b ]

Data digest calculation iterates over command mapped iovec. However
since commit bac04454ef9f we unmap the iovec before we handle the data
digest, and since commit 69b85e1f1d1d we clear nr_mapped when we unmap
the iov.

Instead of open-coding the command iov traversal, simply call
crypto_ahash_digest with the command sg that is already allocated (we
already do that for the send path). Rename nvmet_tcp_send_ddgst to
nvmet_tcp_calc_ddgst and call it from send and recv paths.

Fixes: 69b85e1f1d1d ("nvmet-tcp: add an helper to free the cmd buffers")
Fixes: bac04454ef9f ("nvmet-tcp: fix kmap leak when data digest in use")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Stable-dep-of: 52a0a9854934 ("nvmet-tcp: add bounds checks in nvmet_tcp_build_pdu_iovec")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/target/tcp.c | 23 +++--------------------
 1 file changed, 3 insertions(+), 20 deletions(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index bf3585652c681..3b32f1e9c18c6 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -407,7 +407,7 @@ static int nvmet_tcp_map_data(struct nvmet_tcp_cmd *cmd)
 	return NVME_SC_INTERNAL;
 }
 
-static void nvmet_tcp_send_ddgst(struct ahash_request *hash,
+static void nvmet_tcp_calc_ddgst(struct ahash_request *hash,
 		struct nvmet_tcp_cmd *cmd)
 {
 	ahash_request_set_crypt(hash, cmd->req.sg,
@@ -415,23 +415,6 @@ static void nvmet_tcp_send_ddgst(struct ahash_request *hash,
 	crypto_ahash_digest(hash);
 }
 
-static void nvmet_tcp_recv_ddgst(struct ahash_request *hash,
-		struct nvmet_tcp_cmd *cmd)
-{
-	struct scatterlist sg;
-	struct kvec *iov;
-	int i;
-
-	crypto_ahash_init(hash);
-	for (i = 0, iov = cmd->iov; i < cmd->nr_mapped; i++, iov++) {
-		sg_init_one(&sg, iov->iov_base, iov->iov_len);
-		ahash_request_set_crypt(hash, &sg, NULL, iov->iov_len);
-		crypto_ahash_update(hash);
-	}
-	ahash_request_set_crypt(hash, NULL, (void *)&cmd->exp_ddgst, 0);
-	crypto_ahash_final(hash);
-}
-
 static void nvmet_setup_c2h_data_pdu(struct nvmet_tcp_cmd *cmd)
 {
 	struct nvme_tcp_data_pdu *pdu = cmd->data_pdu;
@@ -456,7 +439,7 @@ static void nvmet_setup_c2h_data_pdu(struct nvmet_tcp_cmd *cmd)
 
 	if (queue->data_digest) {
 		pdu->hdr.flags |= NVME_TCP_F_DDGST;
-		nvmet_tcp_send_ddgst(queue->snd_hash, cmd);
+		nvmet_tcp_calc_ddgst(queue->snd_hash, cmd);
 	}
 
 	if (cmd->queue->hdr_digest) {
@@ -1168,7 +1151,7 @@ static void nvmet_tcp_prep_recv_ddgst(struct nvmet_tcp_cmd *cmd)
 {
 	struct nvmet_tcp_queue *queue = cmd->queue;
 
-	nvmet_tcp_recv_ddgst(queue->rcv_hash, cmd);
+	nvmet_tcp_calc_ddgst(queue->rcv_hash, cmd);
 	queue->offset = 0;
 	queue->left = NVME_TCP_DIGEST_LENGTH;
 	queue->rcv_state = NVMET_TCP_RECV_DDGST;
-- 
2.51.0