From mboxrd@z Thu Jan 1 00:00:00 1970 From: lixiubo@cmss.chinamobile.com Subject: [PATCHv4 1/4] tcmu: Fix possible overwrite of t_data_sg's last iov[] Date: Tue, 21 Mar 2017 16:36:19 +0800 Message-ID: <1490085382-28658-2-git-send-email-lixiubo@cmss.chinamobile.com> References: <1490085382-28658-1-git-send-email-lixiubo@cmss.chinamobile.com> Return-path: In-Reply-To: <1490085382-28658-1-git-send-email-lixiubo@cmss.chinamobile.com> Sender: target-devel-owner@vger.kernel.org To: agrover@redhat.com, nab@linux-iscsi.org, mchristi@redhat.com Cc: shli@kernel.org, sheng@yasker.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, namei.unix@gmail.com, bryantly@linux.vnet.ibm.com, Xiubo Li List-Id: linux-scsi@vger.kernel.org From: Xiubo Li 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. Signed-off-by: Xiubo Li Signed-off-by: Bryant G. Ly --- drivers/target/target_core_user.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 57defc3..65d475f 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -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 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t d 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 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t d 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 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t d 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); -- 1.8.3.1