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authorBart Van Assche <bvanassche@acm.org>2019-11-13 14:05:07 -0800
committerMartin K. Petersen <martin.petersen@oracle.com>2019-11-19 21:37:35 -0500
commit80647a89eaf3f2549741648f3230cd6ff68c23b4 (patch)
tree2aba65377688791dd0a098b347558b75c5f49528 /drivers/target
parent11bf1d14b2d6fd4f144d8ee3ac2e71057fc0ec35 (diff)
downloadlinux-80647a89eaf3f2549741648f3230cd6ff68c23b4.tar.bz2
scsi: target: core: Release SPC-2 reservations when closing a session
The SCSI specs require releasing SPC-2 reservations when a session is closed. Make sure that the target core does this. Running the libiscsi tests triggers the KASAN complaint shown below. This patch fixes that use-after-free. BUG: KASAN: use-after-free in target_check_reservation+0x171/0x980 [target_core_mod] Read of size 8 at addr ffff88802ecd1878 by task iscsi_trx/17200 CPU: 0 PID: 17200 Comm: iscsi_trx Not tainted 5.4.0-rc1-dbg+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x8a/0xd6 print_address_description.constprop.0+0x40/0x60 __kasan_report.cold+0x1b/0x34 kasan_report+0x16/0x20 __asan_load8+0x58/0x90 target_check_reservation+0x171/0x980 [target_core_mod] __target_execute_cmd+0xb1/0xf0 [target_core_mod] target_execute_cmd+0x22d/0x4d0 [target_core_mod] transport_generic_new_cmd+0x31f/0x5b0 [target_core_mod] transport_handle_cdb_direct+0x6f/0x90 [target_core_mod] iscsit_execute_cmd+0x381/0x3f0 [iscsi_target_mod] iscsit_sequence_cmd+0x13b/0x1f0 [iscsi_target_mod] iscsit_process_scsi_cmd+0x4c/0x130 [iscsi_target_mod] iscsit_get_rx_pdu+0x8e8/0x15f0 [iscsi_target_mod] iscsi_target_rx_thread+0x105/0x1b0 [iscsi_target_mod] kthread+0x1bc/0x210 ret_from_fork+0x24/0x30 Allocated by task 1079: save_stack+0x23/0x90 __kasan_kmalloc.constprop.0+0xcf/0xe0 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc+0xfe/0x3a0 transport_alloc_session+0x29/0x80 [target_core_mod] iscsi_target_login_thread+0xceb/0x1920 [iscsi_target_mod] kthread+0x1bc/0x210 ret_from_fork+0x24/0x30 Freed by task 17193: save_stack+0x23/0x90 __kasan_slab_free+0x13a/0x190 kasan_slab_free+0x12/0x20 kmem_cache_free+0xc8/0x3e0 transport_free_session+0x179/0x2f0 [target_core_mod] transport_deregister_session+0x121/0x170 [target_core_mod] iscsit_close_session+0x12c/0x350 [iscsi_target_mod] iscsit_logout_post_handler+0x136/0x380 [iscsi_target_mod] iscsit_response_queue+0x8fa/0xc00 [iscsi_target_mod] iscsi_target_tx_thread+0x28e/0x390 [iscsi_target_mod] kthread+0x1bc/0x210 ret_from_fork+0x24/0x30 The buggy address belongs to the object at ffff88802ecd1860 which belongs to the cache se_sess_cache of size 352 The buggy address is located 24 bytes inside of 352-byte region [ffff88802ecd1860, ffff88802ecd19c0) The buggy address belongs to the page: page:ffffea0000bb3400 refcount:1 mapcount:0 mapping:ffff8880bef2ed00 index:0x0 compound_mapcount: 0 flags: 0x1000000000010200(slab|head) raw: 1000000000010200 dead000000000100 dead000000000122 ffff8880bef2ed00 raw: 0000000000000000 0000000080270027 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88802ecd1700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ecd1780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802ecd1800: fb fb fb fb fc fc fc fc fc fc fc fc fb fb fb fb ^ ffff88802ecd1880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ecd1900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb Cc: Mike Christie <mchristi@redhat.com> Link: https://lore.kernel.org/r/20191113220508.198257-2-bvanassche@acm.org Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_transport.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 652ef1c9a9f6..ea482d4b1f00 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -584,6 +584,15 @@ void transport_free_session(struct se_session *se_sess)
}
EXPORT_SYMBOL(transport_free_session);
+static int target_release_res(struct se_device *dev, void *data)
+{
+ struct se_session *sess = data;
+
+ if (dev->reservation_holder == sess)
+ target_release_reservation(dev);
+ return 0;
+}
+
void transport_deregister_session(struct se_session *se_sess)
{
struct se_portal_group *se_tpg = se_sess->se_tpg;
@@ -600,6 +609,12 @@ void transport_deregister_session(struct se_session *se_sess)
se_sess->fabric_sess_ptr = NULL;
spin_unlock_irqrestore(&se_tpg->session_lock, flags);
+ /*
+ * Since the session is being removed, release SPC-2
+ * reservations held by the session that is disappearing.
+ */
+ target_for_each_device(target_release_res, se_sess);
+
pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
se_tpg->se_tpg_tfo->fabric_name);
/*