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Haoran Zhang 221af82f60 vhost/scsi: null-ptr-dereference in vhost_scsi_get_req()
Since commit 3f8ca2e115 ("vhost/scsi: Extract common handling code
from control queue handler") a null pointer dereference bug can be
triggered when guest sends an SCSI AN request.

In vhost_scsi_ctl_handle_vq(), `vc.target` is assigned with
`&v_req.tmf.lun[1]` within a switch-case block and is then passed to
vhost_scsi_get_req() which extracts `vc->req` and `tpg`. However, for
a `VIRTIO_SCSI_T_AN_*` request, tpg is not required, so `vc.target` is
set to NULL in this branch. Later, in vhost_scsi_get_req(),
`vc->target` is dereferenced without being checked, leading to a null
pointer dereference bug. This bug can be triggered from guest.

When this bug occurs, the vhost_worker process is killed while holding
`vq->mutex` and the corresponding tpg will remain occupied
indefinitely.

Below is the KASAN report:
Oops: general protection fault, probably for non-canonical address
0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 840 Comm: poc Not tainted 6.10.0+ #1
Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:vhost_scsi_get_req+0x165/0x3a0
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 2b 02 00 00
48 b8 00 00 00 00 00 fc ff df 4d 8b 65 30 4c 89 e2 48 c1 ea 03 <0f> b6
04 02 4c 89 e2 83 e2 07 38 d0 7f 08 84 c0 0f 85 be 01 00 00
RSP: 0018:ffff888017affb50 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff88801b000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888017affcb8
RBP: ffff888017affb80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff888017affc88 R14: ffff888017affd1c R15: ffff888017993000
FS:  000055556e076500(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000200027c0 CR3: 0000000010ed0004 CR4: 0000000000370ef0
Call Trace:
 <TASK>
 ? show_regs+0x86/0xa0
 ? die_addr+0x4b/0xd0
 ? exc_general_protection+0x163/0x260
 ? asm_exc_general_protection+0x27/0x30
 ? vhost_scsi_get_req+0x165/0x3a0
 vhost_scsi_ctl_handle_vq+0x2a4/0xca0
 ? __pfx_vhost_scsi_ctl_handle_vq+0x10/0x10
 ? __switch_to+0x721/0xeb0
 ? __schedule+0xda5/0x5710
 ? __kasan_check_write+0x14/0x30
 ? _raw_spin_lock+0x82/0xf0
 vhost_scsi_ctl_handle_kick+0x52/0x90
 vhost_run_work_list+0x134/0x1b0
 vhost_task_fn+0x121/0x350
...
 </TASK>
---[ end trace 0000000000000000 ]---

Let's add a check in vhost_scsi_get_req.

Fixes: 3f8ca2e115 ("vhost/scsi: Extract common handling code from control queue handler")
Signed-off-by: Haoran Zhang <wh1sper@zju.edu.cn>
[whitespace fixes]
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <b26d7ddd-b098-4361-88f8-17ca7f90adf7@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-10-07 11:47:56 -04:00
arch Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging 2024-09-01 09:18:48 +12:00
block block: fix detection of unsupported WRITE SAME in blkdev_issue_write_zeroes 2024-08-28 08:49:25 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto crypto: testmgr - generate power-of-2 lengths more often 2024-07-13 11:50:28 +12:00
Documentation USB fixes for 6.11-rc6 2024-09-01 07:06:28 +12:00
drivers vhost/scsi: null-ptr-dereference in vhost_scsi_get_req() 2024-10-07 11:47:56 -04:00
fs virtio_fs: add sysfs entries for queue information 2024-09-25 07:07:43 -04:00
include vdpa: support set mac address from vdpa tool 2024-09-10 02:51:48 -04:00
init Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
io_uring io_uring/kbuf: return correct iovec count from classic buffer peek 2024-08-30 10:45:54 -06:00
ipc sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kernel vfs-6.11-rc6.fixes 2024-08-27 16:57:35 +12:00
lib Random number generator fixes for Linux 6.11-rc6. 2024-08-29 13:59:18 +12:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: Fix missing folio invalidation calls during truncation 2024-08-24 16:09:16 +02:00
net vsock/virtio: use GFP_ATOMIC under RCU read lock 2024-10-07 11:47:55 -04:00
rust Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
samples treewide: remove unnecessary <linux/version.h> inclusion 2024-08-12 18:36:44 +09:00
scripts net: drop special comment style 2024-08-23 10:21:02 +01:00
security Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging 2024-09-01 09:18:48 +12:00
sound sound fixes for 6.11-rc6 2024-08-28 06:24:22 +12:00
tools tools/virtio:Fix the wrong format specifier 2024-09-10 02:51:48 -04:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) 2024-08-14 12:28:24 -04:00
.clang-format Docs: Move clang-format from process/ to dev-tools/ 2024-06-26 16:36:00 -06:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: add script and target to generate pacman package 2024-07-22 01:24:22 +09:00
.mailmap ARM: SoC fixes for 6.11, part 2 2024-09-01 06:42:13 +12:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS tracing: Update of MAINTAINERS and CREDITS file 2024-07-18 14:08:42 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: add virtio-vsock driver in the VIRTIO CORE section 2024-09-25 07:07:43 -04:00
Makefile Linux 6.11-rc6 2024-09-01 19:46:02 +12:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.