From fc09149df6e20cfbb0bb86f10899607c321a31eb Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Thu, 30 Jan 2014 13:08:49 -0800 Subject: [PATCH] target: Fix free-after-use regression in PR unregister 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 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 Cc: Andy Grover Cc: #3.11+ Signed-off-by: Nicholas Bellinger --- 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 2f5d77932c80..3013287a2aaa 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; } -- 2.20.1