linux.git/fs/io_uring.c, branch v5.4.64

io_uring: Fix NULL pointer dereference in io_sq_wq_submit_work()

2020-09-03T09:27:11+00:00

the commit <1c4404efcf2c0> ("") caused a crash in io_sq_wq_submit_work().
when io_ring-wq get a req form async_list, which not have been
added to task_list. Then try to delete the req from task_list will caused
a "NULL pointer dereference".

Ensure add req to async_list and task_list at the sametime.

The crash log looks like this:
[95995.973638] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[95995.979123] pgd = c20c8964
[95995.981803] [00000000] *pgd=1c72d831, *pte=00000000, *ppte=00000000
[95995.988043] Internal error: Oops: 817 [#1] SMP ARM
[95995.992814] Modules linked in: bpfilter(-)
[95995.996898] CPU: 1 PID: 15661 Comm: kworker/u8:5 Not tainted 5.4.56 #2
[95996.003406] Hardware name: Amlogic Meson platform
[95996.008108] Workqueue: io_ring-wq io_sq_wq_submit_work
[95996.013224] PC is at io_sq_wq_submit_work+0x1f4/0x5c4
[95996.018261] LR is at walk_stackframe+0x24/0x40
[95996.022685] pc : []    lr : []    psr: 600f0093
[95996.028936] sp : dc6f7e88  ip : dc6f7df0  fp : dc6f7ef4
[95996.034148] r10: deff9800  r9 : dc1d1694  r8 : dda58b80
[95996.039358] r7 : dc6f6000  r6 : dc6f7ebc  r5 : dc1d1600  r4 : deff99c0
[95996.045871] r3 : 0000cb5d  r2 : 00000000  r1 : ef6b9b80  r0 : c059b88c
[95996.052385] Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
[95996.059593] Control: 10c5387d  Table: 22be804a  DAC: 00000055
[95996.065325] Process kworker/u8:5 (pid: 15661, stack limit = 0x78013c69)
[95996.071923] Stack: (0xdc6f7e88 to 0xdc6f8000)
[95996.076268] 7e80:                   dc6f7ecc dc6f7e98 00000000 c1f06c08 de9dc800 deff9a04
[95996.084431] 7ea0: 00000000 dc6f7f7c 00000000 c1f65808 0000080c dc677a00 c1ee9bd0 dc6f7ebc
[95996.092594] 7ec0: dc6f7ebc d085c8f6 c0445a90 dc1d1e00 e008f300 c0288400 e4ef7100 00000000
[95996.100757] 7ee0: c20d45b0 e4ef7115 dc6f7f34 dc6f7ef8 c03725f0 c059b6b0 c0288400 c0288400
[95996.108921] 7f00: c0288400 00000001 c0288418 e008f300 c0288400 e008f314 00000088 c0288418
[95996.117083] 7f20: c1f03d00 dc6f6038 dc6f7f7c dc6f7f38 c0372df8 c037246c dc6f7f5c 00000000
[95996.125245] 7f40: c1f03d00 c1f03d00 c20d3cbe c0288400 dc6f7f7c e1c43880 e4fa7980 00000000
[95996.133409] 7f60: e008f300 c0372d9c e48bbe74 e1c4389c dc6f7fac dc6f7f80 c0379244 c0372da8
[95996.141570] 7f80: 600f0093 e4fa7980 c0379108 00000000 00000000 00000000 00000000 00000000
[95996.149734] 7fa0: 00000000 dc6f7fb0 c03010ac c0379114 00000000 00000000 00000000 00000000
[95996.157897] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[95996.166060] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[95996.174217] Backtrace:
[95996.176662] [] (io_sq_wq_submit_work) from [] (process_one_work+0x190/0x4c0)
[95996.185425]  r10:e4ef7115 r9:c20d45b0 r8:00000000 r7:e4ef7100 r6:c0288400 r5:e008f300
[95996.193237]  r4:dc1d1e00
[95996.195760] [] (process_one_work) from [] (worker_thread+0x5c/0x5bc)
[95996.203836]  r10:dc6f6038 r9:c1f03d00 r8:c0288418 r7:00000088 r6:e008f314 r5:c0288400
[95996.211647]  r4:e008f300
[95996.214173] [] (worker_thread) from [] (kthread+0x13c/0x168)
[95996.221554]  r10:e1c4389c r9:e48bbe74 r8:c0372d9c r7:e008f300 r6:00000000 r5:e4fa7980
[95996.229363]  r4:e1c43880
[95996.231888] [] (kthread) from [] (ret_from_fork+0x14/0x28)
[95996.239088] Exception stack(0xdc6f7fb0 to 0xdc6f7ff8)
[95996.244127] 7fa0:                                     00000000 00000000 00000000 00000000
[95996.252291] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[95996.260453] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[95996.267054]  r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c0379108
[95996.274866]  r4:e4fa7980 r3:600f0093
[95996.278430] Code: eb3a59e1 e5952098 e5951094 e5812004 (e5821000)

Signed-off-by: Xin Yin 
Signed-off-by: Greg Kroah-Hartman

io_uring: Fix NULL pointer dereference in loop_rw_iter()

2020-08-19T06:16:29+00:00

commit 2dd2111d0d383df104b144e0d1f6b5a00cb7cd88 upstream.

loop_rw_iter() does not check whether the file has a read or
write function. This can lead to NULL pointer dereference
when the user passes in a file descriptor that does not have
read or write function.

The crash log looks like this:

[   99.834071] BUG: kernel NULL pointer dereference, address: 0000000000000000
[   99.835364] #PF: supervisor instruction fetch in kernel mode
[   99.836522] #PF: error_code(0x0010) - not-present page
[   99.837771] PGD 8000000079d62067 P4D 8000000079d62067 PUD 79d8c067 PMD 0
[   99.839649] Oops: 0010 [#2] SMP PTI
[   99.840591] CPU: 1 PID: 333 Comm: io_wqe_worker-0 Tainted: G      D           5.8.0 #2
[   99.842622] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
[   99.845140] RIP: 0010:0x0
[   99.845840] Code: Bad RIP value.
[   99.846672] RSP: 0018:ffffa1c7c01ebc08 EFLAGS: 00010202
[   99.848018] RAX: 0000000000000000 RBX: ffff92363bd67300 RCX: ffff92363d461208
[   99.849854] RDX: 0000000000000010 RSI: 00007ffdbf696bb0 RDI: ffff92363bd67300
[   99.851743] RBP: ffffa1c7c01ebc40 R08: 0000000000000000 R09: 0000000000000000
[   99.853394] R10: ffffffff9ec692a0 R11: 0000000000000000 R12: 0000000000000010
[   99.855148] R13: 0000000000000000 R14: ffff92363d461208 R15: ffffa1c7c01ebc68
[   99.856914] FS:  0000000000000000(0000) GS:ffff92363dd00000(0000) knlGS:0000000000000000
[   99.858651] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   99.860032] CR2: ffffffffffffffd6 CR3: 000000007ac66000 CR4: 00000000000006e0
[   99.861979] Call Trace:
[   99.862617]  loop_rw_iter.part.0+0xad/0x110
[   99.863838]  io_write+0x2ae/0x380
[   99.864644]  ? kvm_sched_clock_read+0x11/0x20
[   99.865595]  ? sched_clock+0x9/0x10
[   99.866453]  ? sched_clock_cpu+0x11/0xb0
[   99.867326]  ? newidle_balance+0x1d4/0x3c0
[   99.868283]  io_issue_sqe+0xd8f/0x1340
[   99.869216]  ? __switch_to+0x7f/0x450
[   99.870280]  ? __switch_to_asm+0x42/0x70
[   99.871254]  ? __switch_to_asm+0x36/0x70
[   99.872133]  ? lock_timer_base+0x72/0xa0
[   99.873155]  ? switch_mm_irqs_off+0x1bf/0x420
[   99.874152]  io_wq_submit_work+0x64/0x180
[   99.875192]  ? kthread_use_mm+0x71/0x100
[   99.876132]  io_worker_handle_work+0x267/0x440
[   99.877233]  io_wqe_worker+0x297/0x350
[   99.878145]  kthread+0x112/0x150
[   99.878849]  ? __io_worker_unuse+0x100/0x100
[   99.879935]  ? kthread_park+0x90/0x90
[   99.880874]  ret_from_fork+0x22/0x30
[   99.881679] Modules linked in:
[   99.882493] CR2: 0000000000000000
[   99.883324] ---[ end trace 4453745f4673190b ]---
[   99.884289] RIP: 0010:0x0
[   99.884837] Code: Bad RIP value.
[   99.885492] RSP: 0018:ffffa1c7c01ebc08 EFLAGS: 00010202
[   99.886851] RAX: 0000000000000000 RBX: ffff92363acd7f00 RCX: ffff92363d461608
[   99.888561] RDX: 0000000000000010 RSI: 00007ffe040d9e10 RDI: ffff92363acd7f00
[   99.890203] RBP: ffffa1c7c01ebc40 R08: 0000000000000000 R09: 0000000000000000
[   99.891907] R10: ffffffff9ec692a0 R11: 0000000000000000 R12: 0000000000000010
[   99.894106] R13: 0000000000000000 R14: ffff92363d461608 R15: ffffa1c7c01ebc68
[   99.896079] FS:  0000000000000000(0000) GS:ffff92363dd00000(0000) knlGS:0000000000000000
[   99.898017] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   99.899197] CR2: ffffffffffffffd6 CR3: 000000007ac66000 CR4: 00000000000006e0

Fixes: 32960613b7c3 ("io_uring: correctly handle non ->{read,write}_iter() file_operations")
Cc: stable@vger.kernel.org
Signed-off-by: Guoyu Huang 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

io_uring: set ctx sq/cq entry count earlier

2020-08-19T06:16:24+00:00

commit bd74048108c179cea0ff52979506164c80f29da7 upstream.

If we hit an earlier error path in io_uring_create(), then we will have
accounted memory, but not set ctx->{sq,cq}_entries yet. Then when the
ring is torn down in error, we use those values to unaccount the memory.

Ensure we set the ctx entries before we're able to hit a potential error
path.

Cc: stable@vger.kernel.org
Reported-by: Tomáš Chaloupka 
Tested-by: Tomáš Chaloupka 
Reviewed-by: Stefano Garzarella 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

io_uring: fix sq array offset calculation

2020-08-19T06:15:57+00:00

[ Upstream commit b36200f543ff07a1cb346aa582349141df2c8068 ]

rings_size() sets sq_offset to the total size of the rings (the returned
value which is used for memory allocation). This is wrong: sq array should
be located within the rings, not after them. Set sq_offset to where it
should be.

Fixes: 75b28affdd6a ("io_uring: allocate the two rings together")
Signed-off-by: Dmitry Vyukov 
Acked-by: Hristo Venev 
Cc: io-uring@vger.kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

fs/io_uring.c: Fix uninitialized variable is referenced in io_submit_sqe

2020-08-19T06:15:53+00:00

the commit  ("opcode>")
caused another vulnerability. After io_get_req(), the sqe_submit struct
in req is not initialized, but the following code defaults that
req->submit.opcode is available.

Signed-off-by: Liu Yong 
Signed-off-by: Sasha Levin

io_uring: Fix use-after-free in io_sq_wq_submit_work()

2020-08-11T13:33:33+00:00

when ctx->sqo_mm is zero, io_sq_wq_submit_work() frees 'req'
without deleting it from 'task_list'. After that, 'req' is
accessed in io_ring_ctx_wait_and_kill() which lead to
a use-after-free.

Signed-off-by: Guoyu Huang 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

io_uring: prevent re-read of sqe->opcode

2020-08-11T13:33:32+00:00

Liu reports that he can trigger a NULL pointer dereference with
IORING_OP_SENDMSG, by changing the sqe->opcode after we've validated
that the previous opcode didn't need a file and didn't assign one.

Ensure we validate and read the opcode only once.

Reported-by: Liu Yong 
Tested-by: Liu Yong 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

io_uring: make sure async workqueue is canceled on exit

2020-07-09T07:37:49+00:00

Track async work items that we queue, so we can safely cancel them
if the ring is closed or the process exits. Newer kernels handle
this automatically with io-wq, but the old workqueue based setup needs
a bit of special help to get there.

There's no upstream variant of this, as that would require backporting
all the io-wq changes from 5.5 and on. Hence I made a one-off that
ensures that we don't leak memory if we have async work items that
need active cancelation (like socket IO).

Reported-by: Agarwal, Anchal 
Tested-by: Agarwal, Anchal 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

io_uring: use kvfree() in io_sqe_buffer_register()

2020-06-17T14:40:26+00:00

commit a8c73c1a614f6da6c0b04c393f87447e28cb6de4 upstream.

Use kvfree() to free the pages and vmas, since they are allocated by
kvmalloc_array() in a loop.

Fixes: d4ef647510b1 ("io_uring: avoid page allocation warnings")
Signed-off-by: Denis Efremov 
Signed-off-by: Jens Axboe 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200605093203.40087-1-efremov@linux.com
Signed-off-by: Greg Kroah-Hartman

io_uring: initialize ctx->sqo_wait earlier

2020-06-07T11:18:50+00:00

[ Upstream commit 583863ed918136412ddf14de2e12534f17cfdc6f ]

Ensure that ctx->sqo_wait is initialized as soon as the ctx is allocated,
instead of deferring it to the offload setup. This fixes a syzbot
reported lockdep complaint, which is really due to trying to wake_up
on an uninitialized wait queue:

RSP: 002b:00007fffb1fb9aa8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441319
RDX: 0000000000000001 RSI: 0000000020000140 RDI: 000000000000047b
RBP: 0000000000010475 R08: 0000000000000001 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402260
R13: 00000000004022f0 R14: 0000000000000000 R15: 0000000000000000
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 7090 Comm: syz-executor222 Not tainted 5.7.0-rc1-next-20200415-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 assign_lock_key kernel/locking/lockdep.c:913 [inline]
 register_lock_class+0x1664/0x1760 kernel/locking/lockdep.c:1225
 __lock_acquire+0x104/0x4c50 kernel/locking/lockdep.c:4234
 lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4934
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
 __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122
 io_cqring_ev_posted+0xa5/0x1e0 fs/io_uring.c:1160
 io_poll_remove_all fs/io_uring.c:4357 [inline]
 io_ring_ctx_wait_and_kill+0x2bc/0x5a0 fs/io_uring.c:7305
 io_uring_create fs/io_uring.c:7843 [inline]
 io_uring_setup+0x115e/0x22b0 fs/io_uring.c:7870
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x441319
Code: e8 5c ae 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffb1fb9aa8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9

Reported-by: syzbot+8c91f5d054e998721c57@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin