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Commit ab22d260 authored by Xiubo Li's avatar Xiubo Li Committed by Nicholas Bellinger
Browse files

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



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: default avatarMike Christie <mchristi@redhat.com>
Tested-by: default avatarIlias Tsitsimpis <iliastsi@arrikto.com>
Reviewed-by: default avatarBryant G. Ly <bryantly@linux.vnet.ibm.com>
Signed-off-by: default avatarXiubo Li <lixiubo@cmss.chinamobile.com>
Cc: stable@vger.kernel.org # 3.18+
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 49cb77e2

drivers/target/target_core_user.c

+23 −11
Original line number Diff line number Diff line
@@ -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 */

	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);

				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);