diff options
author | Nicholas Bellinger <nab@linux-iscsi.org> | 2016-01-07 22:09:27 -0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-03-12 06:37:27 +0100 |
commit | 4a3c526ced412e509a5abc1ed500996b5e1f048b (patch) | |
tree | 592dda9b88ba4070dd86f3146ed829ed12d040a3 /drivers/target/target_core_tpg.c | |
parent | da259399e4874b3ba7a35040eb80ccb3656fe6cd (diff) |
target: Obtain se_node_acl->acl_kref during get_initiator_node_acl
commit 21aaa23b0ebbd19334fa461370c03cbb076b3295 upstream.
This patch addresses a long standing race where obtaining
se_node_acl->acl_kref in __transport_register_session()
happens a bit too late, and leaves open the potential
for core_tpg_del_initiator_node_acl() to hit a NULL
pointer dereference.
Instead, take ->acl_kref in core_tpg_get_initiator_node_acl()
while se_portal_group->acl_node_mutex is held, and move the
final target_put_nacl() from transport_deregister_session()
into transport_free_session() so that fabric driver login
failure handling using the modern method to still work
as expected.
Also, update core_tpg_get_initiator_node_acl() to take
an extra reference for dynamically generated acls for
demo-mode, before returning to fabric caller. Also
update iscsi-target sendtargets special case handling
to use target_tpg_has_node_acl() when checking if
demo_mode_discovery == true during discovery lookup.
Note the existing wait_for_completion(&acl->acl_free_comp)
in core_tpg_del_initiator_node_acl() does not change.
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/target/target_core_tpg.c')
-rw-r--r-- | drivers/target/target_core_tpg.c | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c index 5fb9dd7f08bb..028854cda97b 100644 --- a/drivers/target/target_core_tpg.c +++ b/drivers/target/target_core_tpg.c @@ -75,9 +75,21 @@ struct se_node_acl *core_tpg_get_initiator_node_acl( unsigned char *initiatorname) { struct se_node_acl *acl; - + /* + * Obtain se_node_acl->acl_kref using fabric driver provided + * initiatorname[] during node acl endpoint lookup driven by + * new se_session login. + * + * The reference is held until se_session shutdown -> release + * occurs via fabric driver invoked transport_deregister_session() + * or transport_free_session() code. + */ mutex_lock(&tpg->acl_node_mutex); acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname); + if (acl) { + if (!kref_get_unless_zero(&acl->acl_kref)) + acl = NULL; + } mutex_unlock(&tpg->acl_node_mutex); return acl; @@ -232,6 +244,25 @@ static void target_add_node_acl(struct se_node_acl *acl) acl->initiatorname); } +bool target_tpg_has_node_acl(struct se_portal_group *tpg, + const char *initiatorname) +{ + struct se_node_acl *acl; + bool found = false; + + mutex_lock(&tpg->acl_node_mutex); + list_for_each_entry(acl, &tpg->acl_node_list, acl_list) { + if (!strcmp(acl->initiatorname, initiatorname)) { + found = true; + break; + } + } + mutex_unlock(&tpg->acl_node_mutex); + + return found; +} +EXPORT_SYMBOL(target_tpg_has_node_acl); + struct se_node_acl *core_tpg_check_initiator_node_acl( struct se_portal_group *tpg, unsigned char *initiatorname) @@ -248,6 +279,15 @@ struct se_node_acl *core_tpg_check_initiator_node_acl( acl = target_alloc_node_acl(tpg, initiatorname); if (!acl) return NULL; + /* + * When allocating a dynamically generated node_acl, go ahead + * and take the extra kref now before returning to the fabric + * driver caller. + * + * Note this reference will be released at session shutdown + * time within transport_free_session() code. + */ + kref_get(&acl->acl_kref); acl->dynamic_node_acl = 1; /* |