From: Bart Van Assche bvanassche@acm.org
[ Upstream commit e9d3009cb936bd0faf0719f68d98ad8afb1e613b ]
The iSCSI target driver is the only target driver that does not wait for ongoing commands to finish before freeing a session. Make the iSCSI target driver wait for ongoing commands to finish before freeing a session. This patch fixes the following KASAN complaint:
BUG: KASAN: use-after-free in __lock_acquire+0xb1a/0x2710 Read of size 8 at addr ffff8881154eca70 by task kworker/0:2/247
CPU: 0 PID: 247 Comm: kworker/0:2 Not tainted 5.4.0-rc1-dbg+ #6 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Workqueue: target_completion target_complete_ok_work [target_core_mod] Call Trace: dump_stack+0x8a/0xd6 print_address_description.constprop.0+0x40/0x60 __kasan_report.cold+0x1b/0x33 kasan_report+0x16/0x20 __asan_load8+0x58/0x90 __lock_acquire+0xb1a/0x2710 lock_acquire+0xd3/0x200 _raw_spin_lock_irqsave+0x43/0x60 target_release_cmd_kref+0x162/0x7f0 [target_core_mod] target_put_sess_cmd+0x2e/0x40 [target_core_mod] lio_check_stop_free+0x12/0x20 [iscsi_target_mod] transport_cmd_check_stop_to_fabric+0xd8/0xe0 [target_core_mod] target_complete_ok_work+0x1b0/0x790 [target_core_mod] process_one_work+0x549/0xa40 worker_thread+0x7a/0x5d0 kthread+0x1bc/0x210 ret_from_fork+0x24/0x30
Allocated by task 889: save_stack+0x23/0x90 __kasan_kmalloc.constprop.0+0xcf/0xe0 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc+0xf6/0x360 transport_alloc_session+0x29/0x80 [target_core_mod] iscsi_target_login_thread+0xcd6/0x18f0 [iscsi_target_mod] kthread+0x1bc/0x210 ret_from_fork+0x24/0x30
Freed by task 1025: save_stack+0x23/0x90 __kasan_slab_free+0x13a/0x190 kasan_slab_free+0x12/0x20 kmem_cache_free+0x146/0x400 transport_free_session+0x179/0x2f0 [target_core_mod] transport_deregister_session+0x130/0x180 [target_core_mod] iscsit_close_session+0x12c/0x350 [iscsi_target_mod] iscsit_logout_post_handler+0x136/0x380 [iscsi_target_mod] iscsit_response_queue+0x8de/0xbe0 [iscsi_target_mod] iscsi_target_tx_thread+0x27f/0x370 [iscsi_target_mod] kthread+0x1bc/0x210 ret_from_fork+0x24/0x30
The buggy address belongs to the object at ffff8881154ec9c0 which belongs to the cache se_sess_cache of size 352 The buggy address is located 176 bytes inside of 352-byte region [ffff8881154ec9c0, ffff8881154ecb20) The buggy address belongs to the page: page:ffffea0004553b00 refcount:1 mapcount:0 mapping:ffff888101755400 index:0x0 compound_mapcount: 0 flags: 0x2fff000000010200(slab|head) raw: 2fff000000010200 dead000000000100 dead000000000122 ffff888101755400 raw: 0000000000000000 0000000080130013 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff8881154ec900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881154ec980: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff8881154eca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^ ffff8881154eca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881154ecb00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
Cc: Mike Christie mchristi@redhat.com Link: https://lore.kernel.org/r/20191113220508.198257-3-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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/target/iscsi/iscsi_target.c | 10 ++++++++-- include/scsi/iscsi_proto.h | 1 + 2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index d19e051f2bc23..f194ffc4699e0 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -1165,7 +1165,9 @@ int iscsit_setup_scsi_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd, hdr->cmdsn, be32_to_cpu(hdr->data_length), payload_length, conn->cid);
- target_get_sess_cmd(&cmd->se_cmd, true); + if (target_get_sess_cmd(&cmd->se_cmd, true) < 0) + return iscsit_add_reject_cmd(cmd, + ISCSI_REASON_WAITING_FOR_LOGOUT, buf);
cmd->sense_reason = transport_lookup_cmd_lun(&cmd->se_cmd, scsilun_to_int(&hdr->lun)); @@ -2002,7 +2004,9 @@ iscsit_handle_task_mgt_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd, conn->sess->se_sess, 0, DMA_NONE, TCM_SIMPLE_TAG, cmd->sense_buffer + 2);
- target_get_sess_cmd(&cmd->se_cmd, true); + if (target_get_sess_cmd(&cmd->se_cmd, true) < 0) + return iscsit_add_reject_cmd(cmd, + ISCSI_REASON_WAITING_FOR_LOGOUT, buf);
/* * TASK_REASSIGN for ERL=2 / connection stays inside of @@ -4232,6 +4236,8 @@ int iscsit_close_connection( * must wait until they have completed. */ iscsit_check_conn_usage_count(conn); + target_sess_cmd_list_set_waiting(sess->se_sess); + target_wait_for_sess_cmds(sess->se_sess);
ahash_request_free(conn->conn_tx_hash); if (conn->conn_rx_hash) { diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h index b71b5c4f418c5..533f56733ba84 100644 --- a/include/scsi/iscsi_proto.h +++ b/include/scsi/iscsi_proto.h @@ -627,6 +627,7 @@ struct iscsi_reject { #define ISCSI_REASON_BOOKMARK_INVALID 9 #define ISCSI_REASON_BOOKMARK_NO_RESOURCES 10 #define ISCSI_REASON_NEGOTIATION_RESET 11 +#define ISCSI_REASON_WAITING_FOR_LOGOUT 12
/* Max. number of Key=Value pairs in a text message */ #define MAX_KEY_VALUE_PAIRS 8192