linux-stable.git/drivers/target, branch linux-4.18.y

scsi: iscsi: target: Don't use stack buffer for scatterlist

2018-10-18T07:18:15+00:00

[ Upstream commit 679fcae46c8b2352bba3485d521da070cfbe68e6 ]

Fedora got a bug report of a crash with iSCSI:

kernel BUG at include/linux/scatterlist.h:143!
...
RIP: 0010:iscsit_do_crypto_hash_buf+0x154/0x180 [iscsi_target_mod]
...
 Call Trace:
  ? iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod]
  iscsit_get_rx_pdu+0x4cd/0xa90 [iscsi_target_mod]
  ? native_sched_clock+0x3e/0xa0
  ? iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod]
  iscsi_target_rx_thread+0x81/0xf0 [iscsi_target_mod]
  kthread+0x120/0x140
  ? kthread_create_worker_on_cpu+0x70/0x70
  ret_from_fork+0x3a/0x50

This is a BUG_ON for using a stack buffer with a scatterlist.  There
are two cases that trigger this bug. Switch to using a dynamically
allocated buffer for one case and do not assign a NULL buffer in
another case.

Signed-off-by: Laura Abbott 
Reviewed-by: Mike Christie 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

scsi: iscsi: target: Fix conn_ops double free

2018-10-10T06:55:58+00:00

[ Upstream commit 05a86e78ea9823ec25b3515db078dd8a76fc263c ]

If iscsi_login_init_conn fails it can free conn_ops.
__iscsi_target_login_thread will then call iscsi_target_login_sess_out
which will also free it.

This fixes the problem by organizing conn allocation/setup into parts that
are needed through the life of the conn and parts that are only needed for
the login. The free functions then release what was allocated in the alloc
functions.

With this patch we have:

iscsit_alloc_conn/iscsit_free_conn - allocs/frees the conn we need for the
entire life of the conn.

iscsi_login_init_conn/iscsi_target_nego_release - allocs/frees the parts
of the conn that are only needed during login.

Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

scsi: iscsi: target: Set conn->sess to NULL when iscsi_login_set_conn_values fails

2018-10-10T06:55:58+00:00

[ 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 
[rebased against idr/ida changes and to handle ret review comments from Matthew]
Signed-off-by: Mike Christie 
Cc: Matthew Wilcox 
Reviewed-by: Matthew Wilcox 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

scsi: target: Avoid that EXTENDED COPY commands trigger lock inversion

2018-10-03T23:59:08+00:00

[ Upstream commit 36d4cb460bcbe2a1323732a6e4bb9dd783284368 ]

The approach for adding a device to the devices_idr data structure and for
removing it is as follows:

* &dev->dev_group.cg_item is initialized before a device is added to
  devices_idr.

* If the reference count of a device drops to zero then
  target_free_device() removes the device from devices_idr.

* All devices_idr manipulations are protected by device_mutex.

This means that increasing the reference count of a device is sufficient to
prevent removal from devices_idr and also that it is safe access
dev_group.cg_item for any device that is referenced by devices_idr. Use
this to modify target_find_device() and target_for_each_device() such that
these functions no longer introduce a dependency between device_mutex and
the configfs root inode mutex.

Note: it is safe to pass a NULL pointer to config_item_put() and also to
config_item_get_unless_zero().

This patch prevents that lockdep reports the following complaint:

======================================================
WARNING: possible circular locking dependency detected
4.12.0-rc1-dbg+ #1 Not tainted
------------------------------------------------------
rmdir/12053 is trying to acquire lock:
 (device_mutex#2){+.+.+.}, at: []
target_free_device+0xae/0xf0 [target_core_mod]

but task is already holding lock:
 (&sb->s_type->i_mutex_key#14){++++++}, at: []
vfs_rmdir+0x50/0x140

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#14){++++++}:
       lock_acquire+0x59/0x80
       down_write+0x36/0x70
       configfs_depend_item+0x3a/0xb0 [configfs]
       target_depend_item+0x13/0x20 [target_core_mod]
       target_xcopy_locate_se_dev_e4_iter+0x87/0x100 [target_core_mod]
       target_devices_idr_iter+0x16/0x20 [target_core_mod]
       idr_for_each+0x39/0xc0
       target_for_each_device+0x36/0x50 [target_core_mod]
       target_xcopy_locate_se_dev_e4+0x28/0x80 [target_core_mod]
       target_xcopy_do_work+0x2e9/0xdd0 [target_core_mod]
       process_one_work+0x1ca/0x3f0
       worker_thread+0x49/0x3b0
       kthread+0x109/0x140
       ret_from_fork+0x31/0x40

-> #0 (device_mutex#2){+.+.+.}:
       __lock_acquire+0x101f/0x11d0
       lock_acquire+0x59/0x80
       __mutex_lock+0x7e/0x950
       mutex_lock_nested+0x16/0x20
       target_free_device+0xae/0xf0 [target_core_mod]
       target_core_dev_release+0x10/0x20 [target_core_mod]
       config_item_put+0x6e/0xb0 [configfs]
       configfs_rmdir+0x1a6/0x300 [configfs]
       vfs_rmdir+0xb7/0x140
       do_rmdir+0x1f4/0x200
       SyS_rmdir+0x11/0x20
       entry_SYSCALL_64_fastpath+0x23/0xc2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sb->s_type->i_mutex_key#14);
                               lock(device_mutex#2);
                               lock(&sb->s_type->i_mutex_key#14);
  lock(device_mutex#2);

 *** DEADLOCK ***

3 locks held by rmdir/12053:
 #0:  (sb_writers#10){.+.+.+}, at: []
mnt_want_write+0x1f/0x50
 #1:  (&sb->s_type->i_mutex_key#14/1){+.+.+.}, at: []
do_rmdir+0x15e/0x200
 #2:  (&sb->s_type->i_mutex_key#14){++++++}, at: []
vfs_rmdir+0x50/0x140

stack backtrace:
CPU: 3 PID: 12053 Comm: rmdir Not tainted 4.12.0-rc1-dbg+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.0.0-prebuilt.qemu-project.org 04/01/2014
Call Trace:
 dump_stack+0x86/0xcf
 print_circular_bug+0x1c7/0x220
 __lock_acquire+0x101f/0x11d0
 lock_acquire+0x59/0x80
 __mutex_lock+0x7e/0x950
 mutex_lock_nested+0x16/0x20
 target_free_device+0xae/0xf0 [target_core_mod]
 target_core_dev_release+0x10/0x20 [target_core_mod]
 config_item_put+0x6e/0xb0 [configfs]
 configfs_rmdir+0x1a6/0x300 [configfs]
 vfs_rmdir+0xb7/0x140
 do_rmdir+0x1f4/0x200
 SyS_rmdir+0x11/0x20
 entry_SYSCALL_64_fastpath+0x23/0xc2

Signed-off-by: Bart Van Assche 
[Rebased to handle conflict withe target_find_device removal]
Signed-off-by: Mike Christie 

Signed-off-by: Martin K. Petersen 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

scsi: target/iscsi: Make iscsit_ta_authentication() respect the output buffer size

2018-10-03T23:59:08+00:00

[ Upstream commit 35bea5c84fd13c643cce63f0b5cd4b148f8c901d ]

Fixes: e48354ce078c ("iscsi-target: Add iSCSI fabric support for target v4.1")
Signed-off-by: Bart Van Assche 
Reviewed-by: Mike Christie 
Cc: Mike Christie 
Cc: Christoph Hellwig 
Cc: Hannes Reinecke 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

scsi: target: iscsi: Use bin2hex instead of a re-implementation

2018-09-29T09:55:58+00:00

commit 8c39e2699f8acb2e29782a834e56306da24937fe upstream.

Signed-off-by: Vincent Pelletier 
Reviewed-by: Mike Christie 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Greg Kroah-Hartman

scsi: target: iscsi: Use hex2bin instead of a re-implementation

2018-09-29T09:55:58+00:00

commit 1816494330a83f2a064499d8ed2797045641f92c upstream.

This change has the following effects, in order of descreasing importance:

1) Prevent a stack buffer overflow

2) Do not append an unnecessary NULL to an anyway binary buffer, which
   is writing one byte past client_digest when caller is:
   chap_string_to_hex(client_digest, chap_r, strlen(chap_r));

The latter was found by KASAN (see below) when input value hes expected size
(32 hex chars), and further analysis revealed a stack buffer overflow can
happen when network-received value is longer, allowing an unauthenticated
remote attacker to smash up to 17 bytes after destination buffer (16 bytes
attacker-controlled and one null).  As switching to hex2bin requires
specifying destination buffer length, and does not internally append any null,
it solves both issues.

This addresses CVE-2018-14633.

Beyond this:

- Validate received value length and check hex2bin accepted the input, to log
  this rejection reason instead of just failing authentication.

- Only log received CHAP_R and CHAP_C values once they passed sanity checks.

==================================================================
BUG: KASAN: stack-out-of-bounds in chap_string_to_hex+0x32/0x60 [iscsi_target_mod]
Write of size 1 at addr ffff8801090ef7c8 by task kworker/0:0/1021

CPU: 0 PID: 1021 Comm: kworker/0:0 Tainted: G           O      4.17.8kasan.sess.connops+ #2
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
Workqueue: events iscsi_target_do_login_rx [iscsi_target_mod]
Call Trace:
 dump_stack+0x71/0xac
 print_address_description+0x65/0x22e
 ? chap_string_to_hex+0x32/0x60 [iscsi_target_mod]
 kasan_report.cold.6+0x241/0x2fd
 chap_string_to_hex+0x32/0x60 [iscsi_target_mod]
 chap_server_compute_md5.isra.2+0x2cb/0x860 [iscsi_target_mod]
 ? chap_binaryhex_to_asciihex.constprop.5+0x50/0x50 [iscsi_target_mod]
 ? ftrace_caller_op_ptr+0xe/0xe
 ? __orc_find+0x6f/0xc0
 ? unwind_next_frame+0x231/0x850
 ? kthread+0x1a0/0x1c0
 ? ret_from_fork+0x35/0x40
 ? ret_from_fork+0x35/0x40
 ? iscsi_target_do_login_rx+0x3bc/0x4c0 [iscsi_target_mod]
 ? deref_stack_reg+0xd0/0xd0
 ? iscsi_target_do_login_rx+0x3bc/0x4c0 [iscsi_target_mod]
 ? is_module_text_address+0xa/0x11
 ? kernel_text_address+0x4c/0x110
 ? __save_stack_trace+0x82/0x100
 ? ret_from_fork+0x35/0x40
 ? save_stack+0x8c/0xb0
 ? 0xffffffffc1660000
 ? iscsi_target_do_login+0x155/0x8d0 [iscsi_target_mod]
 ? iscsi_target_do_login_rx+0x3bc/0x4c0 [iscsi_target_mod]
 ? process_one_work+0x35c/0x640
 ? worker_thread+0x66/0x5d0
 ? kthread+0x1a0/0x1c0
 ? ret_from_fork+0x35/0x40
 ? iscsi_update_param_value+0x80/0x80 [iscsi_target_mod]
 ? iscsit_release_cmd+0x170/0x170 [iscsi_target_mod]
 chap_main_loop+0x172/0x570 [iscsi_target_mod]
 ? chap_server_compute_md5.isra.2+0x860/0x860 [iscsi_target_mod]
 ? rx_data+0xd6/0x120 [iscsi_target_mod]
 ? iscsit_print_session_params+0xd0/0xd0 [iscsi_target_mod]
 ? cyc2ns_read_begin.part.2+0x90/0x90
 ? _raw_spin_lock_irqsave+0x25/0x50
 ? memcmp+0x45/0x70
 iscsi_target_do_login+0x875/0x8d0 [iscsi_target_mod]
 ? iscsi_target_check_first_request.isra.5+0x1a0/0x1a0 [iscsi_target_mod]
 ? del_timer+0xe0/0xe0
 ? memset+0x1f/0x40
 ? flush_sigqueue+0x29/0xd0
 iscsi_target_do_login_rx+0x3bc/0x4c0 [iscsi_target_mod]
 ? iscsi_target_nego_release+0x80/0x80 [iscsi_target_mod]
 ? iscsi_target_restore_sock_callbacks+0x130/0x130 [iscsi_target_mod]
 process_one_work+0x35c/0x640
 worker_thread+0x66/0x5d0
 ? flush_rcu_work+0x40/0x40
 kthread+0x1a0/0x1c0
 ? kthread_bind+0x30/0x30
 ret_from_fork+0x35/0x40

The buggy address belongs to the page:
page:ffffea0004243bc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x17fffc000000000()
raw: 017fffc000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: ffffea0004243c20 ffffea0004243ba0 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801090ef680: f2 f2 f2 f2 f2 f2 f2 01 f2 f2 f2 f2 f2 f2 f2 00
 ffff8801090ef700: f2 f2 f2 f2 f2 f2 f2 00 02 f2 f2 f2 f2 f2 f2 00
>ffff8801090ef780: 00 f2 f2 f2 f2 f2 f2 00 00 f2 f2 f2 f2 f2 f2 00
                                              ^
 ffff8801090ef800: 00 f2 f2 f2 f2 f2 f2 00 00 00 00 02 f2 f2 f2 f2
 ffff8801090ef880: f2 f2 f2 00 00 00 00 00 00 00 00 f2 f2 f2 f2 00
==================================================================

Signed-off-by: Vincent Pelletier 
Reviewed-by: Mike Christie 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Greg Kroah-Hartman

scsi: tcmu: do not set max_blocks if data_bitmap has been setup

2018-09-19T20:41:32+00:00

[ Upstream commit c97840c84f5a4362a596a2751e9245a979377a16 ]

This patch prevents a bug where data_bitmap is allocated in
tcmu_configure_device, userspace changes the max_blocks setting, the device
is mapped to a LUN, then we try to access the data_bitmap based on the new
max_blocks limit which may now be out of range.

To prevent this, we just check if data_bitmap has been setup. If it has
then we fail the max_blocks update operation.

Signed-off-by: Mike Christie 
Reviewed-by: Xiubo Li 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

scsi: target: fix __transport_register_session locking

2018-09-19T20:41:26+00:00

[ Upstream commit 6a64f6e1591322beb8ce16e952a53582caf2a15c ]

When __transport_register_session is called from transport_register_session
irqs will already have been disabled, so we do not want the unlock irq call
to enable them until the higher level has done the final
spin_unlock_irqrestore/ spin_unlock_irq.

This has __transport_register_session use the save/restore call.

Signed-off-by: Mike Christie 
Reviewed-by: Bart Van Assche 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

iscsi target: fix session creation failure handling

2018-09-05T07:29:54+00:00

commit 26abc916a898d34c5ad159315a2f683def3c5555 upstream.

The problem is that iscsi_login_zero_tsih_s1 sets conn->sess early in
iscsi_login_set_conn_values. If the function fails later like when we
alloc the idr it does kfree(sess) and leaves the conn->sess pointer set.
iscsi_login_zero_tsih_s1 then returns -Exyz and we then call
iscsi_target_login_sess_out and access the freed memory.

This patch has iscsi_login_zero_tsih_s1 either completely setup the
session or completely tear it down, so later in
iscsi_target_login_sess_out we can just check for it being set to the
connection.

Cc: stable@vger.kernel.org
Fixes: 0957627a9960 ("iscsi-target: Fix sess allocation leak in...")
Signed-off-by: Mike Christie 
Acked-by: Martin K. Petersen 
Signed-off-by: Matthew Wilcox 
Signed-off-by: Greg Kroah-Hartman