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    Subject[PATCH 3.11 101/121] target: Fix free-after-use regression in PR unregister
    Date
    3.11.10.5 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Nicholas Bellinger <nab@linux-iscsi.org>

    commit fc09149df6e20cfbb0bb86f10899607c321a31eb upstream.

    This patch addresses a >= v3.11 free-after-use regression
    in core_scsi3_emulate_pro_register() that was introduced
    in the following commit:

    commit bc118fe4c4a8cfa453491ba77c0a146a6d0e73e0
    Author: Andy Grover <agrover@redhat.com>
    Date: Thu May 16 10:41:04 2013 -0700

    target: Further refactoring of core_scsi3_emulate_pro_register()

    To avoid the free-after-use, save an type value before hand, and
    only call core_scsi3_put_pr_reg() with a valid *pr_reg.

    Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
    Cc: Andy Grover <agrover@redhat.com>
    Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    ---
    drivers/target/target_core_pr.c | 11 +++++++----
    1 file changed, 7 insertions(+), 4 deletions(-)

    diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
    index adec5a8..3408fdd 100644
    --- a/drivers/target/target_core_pr.c
    +++ b/drivers/target/target_core_pr.c
    @@ -2009,7 +2009,7 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
    struct t10_reservation *pr_tmpl = &dev->t10_pr;
    unsigned char isid_buf[PR_REG_ISID_LEN], *isid_ptr = NULL;
    sense_reason_t ret = TCM_NO_SENSE;
    - int pr_holder = 0;
    + int pr_holder = 0, type;

    if (!se_sess || !se_lun) {
    pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
    @@ -2131,6 +2131,7 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
    ret = TCM_RESERVATION_CONFLICT;
    goto out;
    }
    + type = pr_reg->pr_res_type;

    spin_lock(&pr_tmpl->registration_lock);
    /*
    @@ -2161,6 +2162,7 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
    * Release the calling I_T Nexus registration now..
    */
    __core_scsi3_free_registration(cmd->se_dev, pr_reg, NULL, 1);
    + pr_reg = NULL;

    /*
    * From spc4r17, section 5.7.11.3 Unregistering
    @@ -2174,8 +2176,8 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
    * RESERVATIONS RELEASED.
    */
    if (pr_holder &&
    - (pr_reg->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_REGONLY ||
    - pr_reg->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_REGONLY)) {
    + (type == PR_TYPE_WRITE_EXCLUSIVE_REGONLY ||
    + type == PR_TYPE_EXCLUSIVE_ACCESS_REGONLY)) {
    list_for_each_entry(pr_reg_p,
    &pr_tmpl->registration_list,
    pr_reg_list) {
    @@ -2194,7 +2196,8 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
    ret = core_scsi3_update_and_write_aptpl(dev, aptpl);

    out:
    - core_scsi3_put_pr_reg(pr_reg);
    + if (pr_reg)
    + core_scsi3_put_pr_reg(pr_reg);
    return ret;
    }

    --
    1.9.0


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