[PATCH] nvmet-tcp: fix regression in data_digest calculation

Sagi Grimberg
2022-06-23T21:50:09Z

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>
---
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 2793554e622e..0a9542599ad1 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -405,7 +405,7 @@ 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,
@@ -413,23 +413,6 @@ 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;
@@ -454,7 +437,7 @@ 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) {
@@ -1137,7 +1120,7 @@ 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;
--
2.34.1