| From 2dd2111d0d383df104b144e0d1f6b5a00cb7cd88 Mon Sep 17 00:00:00 2001 |
| From: Guoyu Huang <hgy5945@gmail.com> |
| Date: Wed, 5 Aug 2020 03:53:50 -0700 |
| Subject: io_uring: Fix NULL pointer dereference in loop_rw_iter() |
| |
| From: Guoyu Huang <hgy5945@gmail.com> |
| |
| 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 <hgy5945@gmail.com> |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/io_uring.c | 8 ++++++-- |
| 1 file changed, 6 insertions(+), 2 deletions(-) |
| |
| --- a/fs/io_uring.c |
| +++ b/fs/io_uring.c |
| @@ -2614,8 +2614,10 @@ static int io_read(struct io_kiocb *req, |
| |
| if (req->file->f_op->read_iter) |
| ret2 = call_read_iter(req->file, kiocb, &iter); |
| - else |
| + else if (req->file->f_op->read) |
| ret2 = loop_rw_iter(READ, req->file, kiocb, &iter); |
| + else |
| + ret2 = -EINVAL; |
| |
| /* Catch -EAGAIN return for forced non-blocking submission */ |
| if (!force_nonblock || ret2 != -EAGAIN) { |
| @@ -2729,8 +2731,10 @@ static int io_write(struct io_kiocb *req |
| |
| if (req->file->f_op->write_iter) |
| ret2 = call_write_iter(req->file, kiocb, &iter); |
| - else |
| + else if (req->file->f_op->write) |
| ret2 = loop_rw_iter(WRITE, req->file, kiocb, &iter); |
| + else |
| + ret2 = -EINVAL; |
| |
| if (!force_nonblock) |
| current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; |