[PATCH 4.19 59/78] scsi: target: iscsi: Fix data digest calculation

Greg Kroah-Hartman
2020-09-16T00:22:14Z

From: Varun Prakash <varun@chelsio.com>

commit 5528d03183fe5243416c706f64b1faa518b05130 upstream.

Current code does not consider 'page_off' in data digest calculation. To
fix this, add a local variable 'first_sg' and set first_sg.offset to
sg->offset + page_off.

Link: https://lore.kernel.org/r/1598358910-3052-1-git-send-email-varun@chelsio.com
Fixes: e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1")
Cc: <stable@vger.kernel.org>
Reviewed-by: Mike Christie <michael.christie@oralce.com>
Signed-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/target/iscsi/iscsi_target.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -1381,14 +1381,27 @@ static u32 iscsit_do_crypto_hash_sg(
sg = cmd->first_data_sg;
page_off = cmd->first_data_sg_off;

+ if (data_length && page_off) {
+ struct scatterlist first_sg;
+ u32 len = min_t(u32, data_length, sg->length - page_off);
+
+ sg_init_table(&first_sg, 1);
+ sg_set_page(&first_sg, sg_page(sg), len, sg->offset + page_off);
+
+ ahash_request_set_crypt(hash, &first_sg, NULL, len);
+ crypto_ahash_update(hash);
+
+ data_length -= len;
+ sg = sg_next(sg);
+ }
+
while (data_length) {
- u32 cur_len = min_t(u32, data_length, (sg->length - page_off));
+ u32 cur_len = min_t(u32, data_length, sg->length);

ahash_request_set_crypt(hash, sg, NULL, cur_len);
crypto_ahash_update(hash);

data_length -= cur_len;
- page_off = 0;
/* iscsit_map_iovec has already checked for invalid sg pointers */
sg = sg_next(sg);
}