This is a note to let you know that I've just added the patch titled
tcmu: Fix possible overwrite of t_data_sg's last iov[]
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tcmu-fix-possible-overwrite-of-t_data_sg-s-last-iov.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ab22d2604c86ceb01bb2725c9860b88a7dd383bb Mon Sep 17 00:00:00 2001
From: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
Date: Mon, 27 Mar 2017 17:07:40 +0800
Subject: tcmu: Fix possible overwrite of t_data_sg's last iov[]
From: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
commit ab22d2604c86ceb01bb2725c9860b88a7dd383bb upstream.
If there has BIDI data, its first iov[] will overwrite the last
iov[] for se_cmd->t_data_sg.
To fix this, we can just increase the iov pointer, but this may
introuduce a new memory leakage bug: If the se_cmd->data_length
and se_cmd->t_bidi_data_sg->length are all not aligned up to the
DATA_BLOCK_SIZE, the actual length needed maybe larger than just
sum of them.
So, this could be avoided by rounding all the data lengthes up
to DATA_BLOCK_SIZE.
Reviewed-by: Mike Christie <mchristi@xxxxxxxxxx>
Tested-by: Ilias Tsitsimpis <iliastsi@xxxxxxxxxxx>
Reviewed-by: Bryant G. Ly <bryantly@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/target/target_core_user.c | 34 +++++++++++++++++++++++-----------
1 file changed, 23 insertions(+), 11 deletions(-)
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -389,6 +389,20 @@ static bool is_ring_space_avail(struct t
return true;
}
+static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
+{
+ struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
+ size_t data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE);
+
+ if (se_cmd->se_cmd_flags & SCF_BIDI) {
+ BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
+ data_length += round_up(se_cmd->t_bidi_data_sg->length,
+ DATA_BLOCK_SIZE);
+ }
+
+ return data_length;
+}
+
static sense_reason_t
tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
{
@@ -402,7 +416,7 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcm
uint32_t cmd_head;
uint64_t cdb_off;
bool copy_to_data_area;
- size_t data_length;
+ size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS);
if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
@@ -428,11 +442,6 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcm
mb = udev->mb_addr;
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
- data_length = se_cmd->data_length;
- if (se_cmd->se_cmd_flags & SCF_BIDI) {
- BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
- data_length += se_cmd->t_bidi_data_sg->length;
- }
if ((command_size > (udev->cmdr_size / 2)) ||
data_length > udev->data_size) {
pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
@@ -502,11 +511,14 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcm
entry->req.iov_dif_cnt = 0;
/* Handle BIDI commands */
- iov_cnt = 0;
- alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg,
- se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false);
- entry->req.iov_bidi_cnt = iov_cnt;
-
+ if (se_cmd->se_cmd_flags & SCF_BIDI) {
+ iov_cnt = 0;
+ iov++;
+ alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg,
+ se_cmd->t_bidi_data_nents, &iov, &iov_cnt,
+ false);
+ entry->req.iov_bidi_cnt = iov_cnt;
+ }
/* cmd's data_bitmap is what changed in process */
bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap,
DATA_BLOCK_BITS);
Patches currently in stable-queue which might be from lixiubo@xxxxxxxxxxxxxxxxxxxx are
queue-4.9/tcmu-fix-wrongly-calculating-of-the-base_command_size.patch
queue-4.9/tcmu-fix-possible-overwrite-of-t_data_sg-s-last-iov.patch
queue-4.9/tcmu-skip-data-out-blocks-before-gathering-data-in-buffer-for-bidi-case.patch