From f24c7d48a2415ca5ec67d180b45b79fd21f4b2f5 Mon Sep 17 00:00:00 2001
From: David Disseldorp <ddiss@suse.de>
Date: Tue, 3 Nov 2020 02:21:58 +0100
Subject: [PATCH] target: fix XCOPY NAA identifier lookup
Patch-mainline: Not yet, embargoed until 2021-01-12 10:00 PST
References: CVE-2020-28374, bsc#1178372
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")
Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
[ddiss: squash with lun_ref pinning change]
---
drivers/target/target_core_xcopy.c | 115 +++++++++++++++++------------
drivers/target/target_core_xcopy.h | 1 +
2 files changed, 69 insertions(+), 47 deletions(-)
diff --git a/drivers/target/target_core_xcopy.c b/drivers/target/target_core_xcopy.c
index 44e15d7fb2f0..cd38f3c22db6 100644
--- a/drivers/target/target_core_xcopy.c
+++ b/drivers/target/target_core_xcopy.c
@@ -46,60 +46,83 @@ 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;
+ struct se_dev_entry *deve;
+ struct se_node_acl *nacl;
+ struct se_lun *this_lun = NULL;
+ struct se_device *found_dev = NULL;
+ int rc = 0;
- memset(&info, 0, sizeof(info));
- info.dev_wwn = dev_wwn;
+ /* cmd with NULL sess indicates no associated $FABRIC_MOD */
+ if (!sess)
+ goto err_out;
- 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;
+ 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;
+
+ 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,
@@ -246,12 +269,16 @@ 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 - "
@@ -391,18 +418,12 @@ 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 c56a1bde9417..e5f20005179a 100644
--- a/drivers/target/target_core_xcopy.h
+++ b/drivers/target/target_core_xcopy.h
@@ -27,6 +27,7 @@ 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;
--
2.26.2