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tcmu: Fix possible overwrite of t_data_sg's last iov[]

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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@redhat.com>
Tested-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Reviewed-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Cc: stable@vger.kernel.org # 3.18+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Xiubo Li 2017-03-27 17:07:40 +08:00 committed by Nicholas Bellinger
parent 49cb77e297
commit ab22d2604c
1 changed files with 23 additions and 11 deletions
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34
drivers/target/target_core_user.c
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@ -394,6 +394,20 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t d
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)
{
@ -407,7 +421,7 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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))
@ -433,11 +447,6 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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 "
@ -511,11 +520,14 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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);