From: David Disseldorp ddiss@suse.de
stable inclusion from linux-4.19.167 commit fff1180d24e68d697f98642d71444316036a81ff CVE: CVE-2020-28374
--------------------------------
commit 2896c93811e39d63a4d9b63ccf12a8fbc226e5e4 upstream.
When attempting to match EXTENDED COPY CSCD descriptors with corresponding se_devices, target_xcopy_locate_se_dev_e4() currently iterates over LIO's global devices list which includes all configured backstores.
This change ensures that only initiator-accessible backstores are considered during CSCD descriptor lookup, according to the session's se_node_acl LUN list.
To avoid LUN removal race conditions, device pinning is changed from being configfs based to instead using the se_node_acl lun_ref.
Reference: CVE-2020-28374 Fixes: cbf031f425fd ("target: Add support for EXTENDED_COPY copy offload emulation") Reviewed-by: Lee Duncan lduncan@suse.com Signed-off-by: David Disseldorp ddiss@suse.de Signed-off-by: Mike Christie michael.christie@oracle.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/target/target_core_xcopy.c | 119 +++++++++++++++++------------ drivers/target/target_core_xcopy.h | 1 + 2 files changed, 71 insertions(+), 49 deletions(-)
diff --git a/drivers/target/target_core_xcopy.c b/drivers/target/target_core_xcopy.c index 7cdb5d7f6538..1709b8a99bd7 100644 --- a/drivers/target/target_core_xcopy.c +++ b/drivers/target/target_core_xcopy.c @@ -55,60 +55,83 @@ static int target_xcopy_gen_naa_ieee(struct se_device *dev, unsigned char *buf) return 0; }
-struct xcopy_dev_search_info { - const unsigned char *dev_wwn; - struct se_device *found_dev; -}; - +/** + * target_xcopy_locate_se_dev_e4_iter - compare XCOPY NAA device identifiers + * + * @se_dev: device being considered for match + * @dev_wwn: XCOPY requested NAA dev_wwn + * @return: 1 on match, 0 on no-match + */ static int target_xcopy_locate_se_dev_e4_iter(struct se_device *se_dev, - void *data) + const unsigned char *dev_wwn) { - struct xcopy_dev_search_info *info = data; unsigned char tmp_dev_wwn[XCOPY_NAA_IEEE_REGEX_LEN]; int rc;
- if (!se_dev->dev_attrib.emulate_3pc) + if (!se_dev->dev_attrib.emulate_3pc) { + pr_debug("XCOPY: emulate_3pc disabled on se_dev %p\n", se_dev); return 0; + }
memset(&tmp_dev_wwn[0], 0, XCOPY_NAA_IEEE_REGEX_LEN); target_xcopy_gen_naa_ieee(se_dev, &tmp_dev_wwn[0]);
- rc = memcmp(&tmp_dev_wwn[0], info->dev_wwn, XCOPY_NAA_IEEE_REGEX_LEN); - if (rc != 0) - return 0; - - info->found_dev = se_dev; - pr_debug("XCOPY 0xe4: located se_dev: %p\n", se_dev); - - rc = target_depend_item(&se_dev->dev_group.cg_item); + rc = memcmp(&tmp_dev_wwn[0], dev_wwn, XCOPY_NAA_IEEE_REGEX_LEN); if (rc != 0) { - pr_err("configfs_depend_item attempt failed: %d for se_dev: %p\n", - rc, se_dev); - return rc; + pr_debug("XCOPY: skip non-matching: %*ph\n", + XCOPY_NAA_IEEE_REGEX_LEN, tmp_dev_wwn); + return 0; } + pr_debug("XCOPY 0xe4: located se_dev: %p\n", se_dev);
- pr_debug("Called configfs_depend_item for se_dev: %p se_dev->se_dev_group: %p\n", - se_dev, &se_dev->dev_group); return 1; }
-static int target_xcopy_locate_se_dev_e4(const unsigned char *dev_wwn, - struct se_device **found_dev) +static int target_xcopy_locate_se_dev_e4(struct se_session *sess, + const unsigned char *dev_wwn, + struct se_device **_found_dev, + struct percpu_ref **_found_lun_ref) { - struct xcopy_dev_search_info info; - int ret; - - memset(&info, 0, sizeof(info)); - info.dev_wwn = dev_wwn; - - ret = target_for_each_device(target_xcopy_locate_se_dev_e4_iter, &info); - if (ret == 1) { - *found_dev = info.found_dev; - return 0; - } else { - pr_debug_ratelimited("Unable to locate 0xe4 descriptor for EXTENDED_COPY\n"); - return -EINVAL; + struct se_dev_entry *deve; + struct se_node_acl *nacl; + struct se_lun *this_lun = NULL; + struct se_device *found_dev = NULL; + + /* cmd with NULL sess indicates no associated $FABRIC_MOD */ + if (!sess) + goto err_out; + + pr_debug("XCOPY 0xe4: searching for: %*ph\n", + XCOPY_NAA_IEEE_REGEX_LEN, dev_wwn); + + nacl = sess->se_node_acl; + rcu_read_lock(); + hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) { + struct se_device *this_dev; + int rc; + + this_lun = rcu_dereference(deve->se_lun); + this_dev = rcu_dereference_raw(this_lun->lun_se_dev); + + rc = target_xcopy_locate_se_dev_e4_iter(this_dev, dev_wwn); + if (rc) { + if (percpu_ref_tryget_live(&this_lun->lun_ref)) + found_dev = this_dev; + break; + } } + rcu_read_unlock(); + if (found_dev == NULL) + goto err_out; + + pr_debug("lun_ref held for se_dev: %p se_dev->se_dev_group: %p\n", + found_dev, &found_dev->dev_group); + *_found_dev = found_dev; + *_found_lun_ref = &this_lun->lun_ref; + return 0; +err_out: + pr_debug_ratelimited("Unable to locate 0xe4 descriptor for EXTENDED_COPY\n"); + return -EINVAL; }
static int target_xcopy_parse_tiddesc_e4(struct se_cmd *se_cmd, struct xcopy_op *xop, @@ -255,12 +278,16 @@ static int target_xcopy_parse_target_descriptors(struct se_cmd *se_cmd,
switch (xop->op_origin) { case XCOL_SOURCE_RECV_OP: - rc = target_xcopy_locate_se_dev_e4(xop->dst_tid_wwn, - &xop->dst_dev); + rc = target_xcopy_locate_se_dev_e4(se_cmd->se_sess, + xop->dst_tid_wwn, + &xop->dst_dev, + &xop->remote_lun_ref); break; case XCOL_DEST_RECV_OP: - rc = target_xcopy_locate_se_dev_e4(xop->src_tid_wwn, - &xop->src_dev); + rc = target_xcopy_locate_se_dev_e4(se_cmd->se_sess, + xop->src_tid_wwn, + &xop->src_dev, + &xop->remote_lun_ref); break; default: pr_err("XCOPY CSCD descriptor IDs not found in CSCD list - " @@ -412,18 +439,12 @@ static int xcopy_pt_get_cmd_state(struct se_cmd *se_cmd)
static void xcopy_pt_undepend_remotedev(struct xcopy_op *xop) { - struct se_device *remote_dev; - if (xop->op_origin == XCOL_SOURCE_RECV_OP) - remote_dev = xop->dst_dev; + pr_debug("putting dst lun_ref for %p\n", xop->dst_dev); else - remote_dev = xop->src_dev; - - pr_debug("Calling configfs_undepend_item for" - " remote_dev: %p remote_dev->dev_group: %p\n", - remote_dev, &remote_dev->dev_group.cg_item); + pr_debug("putting src lun_ref for %p\n", xop->src_dev);
- target_undepend_item(&remote_dev->dev_group.cg_item); + percpu_ref_put(xop->remote_lun_ref); }
static void xcopy_pt_release_cmd(struct se_cmd *se_cmd) diff --git a/drivers/target/target_core_xcopy.h b/drivers/target/target_core_xcopy.h index 26ba4c3c9cff..974bc1e19ff2 100644 --- a/drivers/target/target_core_xcopy.h +++ b/drivers/target/target_core_xcopy.h @@ -29,6 +29,7 @@ struct xcopy_op { struct se_device *dst_dev; unsigned char dst_tid_wwn[XCOPY_NAA_IEEE_REGEX_LEN]; unsigned char local_dev_wwn[XCOPY_NAA_IEEE_REGEX_LEN]; + struct percpu_ref *remote_lun_ref;
sector_t src_lba; sector_t dst_lba;