4.18-stable review patch. If anyone has any objections, please let me know.
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From: Vincent Pelletier plr.vincent@gmail.com
[ Upstream commit 7915919bb94e12460c58e27c708472e6f85f6699 ]
Fixes a use-after-free reported by KASAN when later iscsi_target_login_sess_out gets called and it tries to access conn->sess->se_sess:
Disabling lock debugging due to kernel taint iSCSI Login timeout on Network Portal [::]:3260 iSCSI Login negotiation failed. ================================================================== BUG: KASAN: use-after-free in iscsi_target_login_sess_out.cold.12+0x58/0xff [iscsi_target_mod] Read of size 8 at addr ffff880109d070c8 by task iscsi_np/980
CPU: 1 PID: 980 Comm: iscsi_np Tainted: G O 4.17.8kasan.sess.connops+ #4 Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 05/19/2014 Call Trace: dump_stack+0x71/0xac print_address_description+0x65/0x22e ? iscsi_target_login_sess_out.cold.12+0x58/0xff [iscsi_target_mod] kasan_report.cold.6+0x241/0x2fd iscsi_target_login_sess_out.cold.12+0x58/0xff [iscsi_target_mod] iscsi_target_login_thread+0x1086/0x1710 [iscsi_target_mod] ? __sched_text_start+0x8/0x8 ? iscsi_target_login_sess_out+0x250/0x250 [iscsi_target_mod] ? __kthread_parkme+0xcc/0x100 ? parse_args.cold.14+0xd3/0xd3 ? iscsi_target_login_sess_out+0x250/0x250 [iscsi_target_mod] kthread+0x1a0/0x1c0 ? kthread_bind+0x30/0x30 ret_from_fork+0x35/0x40
Allocated by task 980: kasan_kmalloc+0xbf/0xe0 kmem_cache_alloc_trace+0x112/0x210 iscsi_target_login_thread+0x816/0x1710 [iscsi_target_mod] kthread+0x1a0/0x1c0 ret_from_fork+0x35/0x40
Freed by task 980: __kasan_slab_free+0x125/0x170 kfree+0x90/0x1d0 iscsi_target_login_thread+0x1577/0x1710 [iscsi_target_mod] kthread+0x1a0/0x1c0 ret_from_fork+0x35/0x40
The buggy address belongs to the object at ffff880109d06f00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 456 bytes inside of 512-byte region [ffff880109d06f00, ffff880109d07100) The buggy address belongs to the page: page:ffffea0004274180 count:1 mapcount:0 mapping:0000000000000000 index:0x0 compound_mapcount: 0 flags: 0x17fffc000008100(slab|head) raw: 017fffc000008100 0000000000000000 0000000000000000 00000001000c000c raw: dead000000000100 dead000000000200 ffff88011b002e00 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff880109d06f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff880109d07000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff880109d07080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^ ffff880109d07100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff880109d07180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================
Signed-off-by: Vincent Pelletier plr.vincent@gmail.com [rebased against idr/ida changes and to handle ret review comments from Matthew] Signed-off-by: Mike Christie mchristi@redhat.com Cc: Matthew Wilcox willy@infradead.org Reviewed-by: Matthew Wilcox willy@infradead.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/target/iscsi/iscsi_target_login.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
--- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -310,11 +310,9 @@ static int iscsi_login_zero_tsih_s1( return -ENOMEM; }
- ret = iscsi_login_set_conn_values(sess, conn, pdu->cid); - if (unlikely(ret)) { - kfree(sess); - return ret; - } + if (iscsi_login_set_conn_values(sess, conn, pdu->cid)) + goto free_sess; + sess->init_task_tag = pdu->itt; memcpy(&sess->isid, pdu->isid, 6); sess->exp_cmd_sn = be32_to_cpu(pdu->cmdsn);