Skip to content

Commit 17b7385

Browse files
mikechristiegregkh
mikechristie
authored and
gregkh
committed
scsi: iscsi_tcp: Fix UAF during logout when accessing the shost ipaddress
[ Upstream commit 6f1d64b ] Bug report and analysis from Ding Hui. During iSCSI session logout, if another task accesses the shost ipaddress attr, we can get a KASAN UAF report like this: [ 276.942144] BUG: KASAN: use-after-free in _raw_spin_lock_bh+0x78/0xe0 [ 276.942535] Write of size 4 at addr ffff8881053b45b8 by task cat/4088 [ 276.943511] CPU: 2 PID: 4088 Comm: cat Tainted: G E 6.1.0-rc8+ #3 [ 276.943997] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 [ 276.944470] Call Trace: [ 276.944943] <TASK> [ 276.945397] dump_stack_lvl+0x34/0x48 [ 276.945887] print_address_description.constprop.0+0x86/0x1e7 [ 276.946421] print_report+0x36/0x4f [ 276.947358] kasan_report+0xad/0x130 [ 276.948234] kasan_check_range+0x35/0x1c0 [ 276.948674] _raw_spin_lock_bh+0x78/0xe0 [ 276.949989] iscsi_sw_tcp_host_get_param+0xad/0x2e0 [iscsi_tcp] [ 276.951765] show_host_param_ISCSI_HOST_PARAM_IPADDRESS+0xe9/0x130 [scsi_transport_iscsi] [ 276.952185] dev_attr_show+0x3f/0x80 [ 276.953005] sysfs_kf_seq_show+0x1fb/0x3e0 [ 276.953401] seq_read_iter+0x402/0x1020 [ 276.954260] vfs_read+0x532/0x7b0 [ 276.955113] ksys_read+0xed/0x1c0 [ 276.955952] do_syscall_64+0x38/0x90 [ 276.956347] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 276.956769] RIP: 0033:0x7f5d3a679222 [ 276.957161] Code: c0 e9 b2 fe ff ff 50 48 8d 3d 32 c0 0b 00 e8 a5 fe 01 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24 [ 276.958009] RSP: 002b:00007ffc864d16a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 276.958431] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f5d3a679222 [ 276.958857] RDX: 0000000000020000 RSI: 00007f5d3a4fe000 RDI: 0000000000000003 [ 276.959281] RBP: 00007f5d3a4fe000 R08: 00000000ffffffff R09: 0000000000000000 [ 276.959682] R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000020000 [ 276.960126] R13: 0000000000000003 R14: 0000000000000000 R15: 0000557a26dada58 [ 276.960536] </TASK> [ 276.961357] Allocated by task 2209: [ 276.961756] kasan_save_stack+0x1e/0x40 [ 276.962170] kasan_set_track+0x21/0x30 [ 276.962557] __kasan_kmalloc+0x7e/0x90 [ 276.962923] __kmalloc+0x5b/0x140 [ 276.963308] iscsi_alloc_session+0x28/0x840 [scsi_transport_iscsi] [ 276.963712] iscsi_session_setup+0xda/0xba0 [libiscsi] [ 276.964078] iscsi_sw_tcp_session_create+0x1fd/0x330 [iscsi_tcp] [ 276.964431] iscsi_if_create_session.isra.0+0x50/0x260 [scsi_transport_iscsi] [ 276.964793] iscsi_if_recv_msg+0xc5a/0x2660 [scsi_transport_iscsi] [ 276.965153] iscsi_if_rx+0x198/0x4b0 [scsi_transport_iscsi] [ 276.965546] netlink_unicast+0x4d5/0x7b0 [ 276.965905] netlink_sendmsg+0x78d/0xc30 [ 276.966236] sock_sendmsg+0xe5/0x120 [ 276.966576] ____sys_sendmsg+0x5fe/0x860 [ 276.966923] ___sys_sendmsg+0xe0/0x170 [ 276.967300] __sys_sendmsg+0xc8/0x170 [ 276.967666] do_syscall_64+0x38/0x90 [ 276.968028] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 276.968773] Freed by task 2209: [ 276.969111] kasan_save_stack+0x1e/0x40 [ 276.969449] kasan_set_track+0x21/0x30 [ 276.969789] kasan_save_free_info+0x2a/0x50 [ 276.970146] __kasan_slab_free+0x106/0x190 [ 276.970470] __kmem_cache_free+0x133/0x270 [ 276.970816] device_release+0x98/0x210 [ 276.971145] kobject_cleanup+0x101/0x360 [ 276.971462] iscsi_session_teardown+0x3fb/0x530 [libiscsi] [ 276.971775] iscsi_sw_tcp_session_destroy+0xd8/0x130 [iscsi_tcp] [ 276.972143] iscsi_if_recv_msg+0x1bf1/0x2660 [scsi_transport_iscsi] [ 276.972485] iscsi_if_rx+0x198/0x4b0 [scsi_transport_iscsi] [ 276.972808] netlink_unicast+0x4d5/0x7b0 [ 276.973201] netlink_sendmsg+0x78d/0xc30 [ 276.973544] sock_sendmsg+0xe5/0x120 [ 276.973864] ____sys_sendmsg+0x5fe/0x860 [ 276.974248] ___sys_sendmsg+0xe0/0x170 [ 276.974583] __sys_sendmsg+0xc8/0x170 [ 276.974891] do_syscall_64+0x38/0x90 [ 276.975216] entry_SYSCALL_64_after_hwframe+0x63/0xcd We can easily reproduce by two tasks: 1. while :; do iscsiadm -m node --login; iscsiadm -m node --logout; done 2. while :; do cat \ /sys/devices/platform/host*/iscsi_host/host*/ipaddress; done iscsid | cat --------------------------------+--------------------------------------- |- iscsi_sw_tcp_session_destroy | |- iscsi_session_teardown | |- device_release | |- iscsi_session_release ||- dev_attr_show |- kfree | |- show_host_param_ | ISCSI_HOST_PARAM_IPADDRESS | |- iscsi_sw_tcp_host_get_param | |- r/w tcp_sw_host->session (UAF) |- iscsi_host_remove | |- iscsi_host_free | Fix the above bug by splitting the session removal into 2 parts: 1. removal from iSCSI class which includes sysfs and removal from host tracking. 2. freeing of session. During iscsi_tcp host and session removal we can remove the session from sysfs then remove the host from sysfs. At this point we know userspace is not accessing the kernel via sysfs so we can free the session and host. Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Mike Christie <[email protected]> Reviewed-by: Lee Duncan <[email protected]> Acked-by: Ding Hui <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
1 parent 8cd0499 commit 17b7385

File tree

3 files changed

+42
-9
lines changed

3 files changed

+42
-9
lines changed

‎drivers/scsi/iscsi_tcp.c‎

Lines changed: 9 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -982,10 +982,17 @@ static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session *cls_session)
982982
if (WARN_ON_ONCE(session->leadconn))
983983
return;
984984

985+
iscsi_session_remove(cls_session);
986+
/*
987+
* Our get_host_param needs to access the session, so remove the
988+
* host from sysfs before freeing the session to make sure userspace
989+
* is no longer accessing the callout.
990+
*/
991+
iscsi_host_remove(shost, false);
992+
985993
iscsi_tcp_r2tpool_free(cls_session->dd_data);
986-
iscsi_session_teardown(cls_session);
987994

988-
iscsi_host_remove(shost, false);
995+
iscsi_session_free(cls_session);
989996
iscsi_host_free(shost);
990997
}
991998

‎drivers/scsi/libiscsi.c‎

Lines changed: 31 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -3024,17 +3024,32 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
30243024
}
30253025
EXPORT_SYMBOL_GPL(iscsi_session_setup);
30263026

3027-
/**
3028-
* iscsi_session_teardown - destroy session, host, and cls_session
3029-
* @cls_session: iscsi session
3027+
/*
3028+
* issi_session_remove - Remove session from iSCSI class.
30303029
*/
3031-
void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
3030+
void iscsi_session_remove(struct iscsi_cls_session *cls_session)
30323031
{
30333032
struct iscsi_session *session = cls_session->dd_data;
3034-
struct module *owner = cls_session->transport->owner;
30353033
struct Scsi_Host *shost = session->host;
30363034

30373035
iscsi_remove_session(cls_session);
3036+
/*
3037+
* host removal only has to wait for its children to be removed from
3038+
* sysfs, and iscsi_tcp needs to do iscsi_host_remove before freeing
3039+
* the session, so drop the session count here.
3040+
*/
3041+
iscsi_host_dec_session_cnt(shost);
3042+
}
3043+
EXPORT_SYMBOL_GPL(iscsi_session_remove);
3044+
3045+
/**
3046+
* iscsi_session_free - Free iscsi session and it's resources
3047+
* @cls_session: iscsi session
3048+
*/
3049+
void iscsi_session_free(struct iscsi_cls_session *cls_session)
3050+
{
3051+
struct iscsi_session *session = cls_session->dd_data;
3052+
struct module *owner = cls_session->transport->owner;
30383053

30393054
iscsi_pool_free(&session->cmdpool);
30403055
kfree(session->password);
@@ -3052,10 +3067,19 @@ void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
30523067
kfree(session->discovery_parent_type);
30533068

30543069
iscsi_free_session(cls_session);
3055-
3056-
iscsi_host_dec_session_cnt(shost);
30573070
module_put(owner);
30583071
}
3072+
EXPORT_SYMBOL_GPL(iscsi_session_free);
3073+
3074+
/**
3075+
* iscsi_session_teardown - destroy session and cls_session
3076+
* @cls_session: iscsi session
3077+
*/
3078+
void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
3079+
{
3080+
iscsi_session_remove(cls_session);
3081+
iscsi_session_free(cls_session);
3082+
}
30593083
EXPORT_SYMBOL_GPL(iscsi_session_teardown);
30603084

30613085
/**

‎include/scsi/libiscsi.h‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -414,6 +414,8 @@ extern int iscsi_host_get_max_scsi_cmds(struct Scsi_Host *shost,
414414
extern struct iscsi_cls_session *
415415
iscsi_session_setup(struct iscsi_transport *, struct Scsi_Host *shost,
416416
uint16_t, int, int, uint32_t, unsigned int);
417+
void iscsi_session_remove(struct iscsi_cls_session *cls_session);
418+
void iscsi_session_free(struct iscsi_cls_session *cls_session);
417419
extern void iscsi_session_teardown(struct iscsi_cls_session *);
418420
extern void iscsi_session_recovery_timedout(struct iscsi_cls_session *);
419421
extern int iscsi_set_param(struct iscsi_cls_conn *cls_conn,

0 commit comments

Comments
 (0)