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scsi: target: Fix XCOPY NAA identifier lookup

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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: cbf031f425 ("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>
This commit is contained in:
David Disseldorp 2020-11-03 02:21:58 +01:00 committed by Martin K. Petersen
parent e71ba9452f
commit 2896c93811
2 changed files with 69 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

115
drivers/target/target_core_xcopy.c
View File

@ -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)
rc = memcmp(&tmp_dev_wwn[0], dev_wwn, XCOPY_NAA_IEEE_REGEX_LEN);
if (rc != 0) {
pr_debug("XCOPY: skip non-matching: %*ph\n",
XCOPY_NAA_IEEE_REGEX_LEN, tmp_dev_wwn);
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);
if (rc != 0) {
pr_err("configfs_depend_item attempt failed: %d for se_dev: %p\n",
rc, se_dev);
return rc;
}
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;
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;
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,
@ -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("putting src lun_ref for %p\n", 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);
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)

1
drivers/target/target_core_xcopy.h
View File

@ -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;