Go to file
Leon Romanovsky 6623e3e3cd RDMA/uverbs: Protect from races between lookup and destroy of uobjects
The race is between lookup_get_idr_uobject and
uverbs_idr_remove_uobj -> uverbs_uobject_put.

We deliberately do not call sychronize_rcu after the idr_remove in
uverbs_idr_remove_uobj for performance reasons, instead we call
kfree_rcu() during uverbs_uobject_put.

However, this means we can obtain pointers to uobj's that have
already been released and must protect against krefing them
using kref_get_unless_zero.

==================================================================
BUG: KASAN: use-after-free in copy_ah_attr_from_uverbs.isra.2+0x860/0xa00
Read of size 4 at addr ffff88005fda1ac8 by task syz-executor2/441

CPU: 1 PID: 441 Comm: syz-executor2 Not tainted 4.15.0-rc2+ #56
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
Call Trace:
dump_stack+0x8d/0xd4
print_address_description+0x73/0x290
kasan_report+0x25c/0x370
? copy_ah_attr_from_uverbs.isra.2+0x860/0xa00
copy_ah_attr_from_uverbs.isra.2+0x860/0xa00
? uverbs_try_lock_object+0x68/0xc0
? modify_qp.isra.7+0xdc4/0x10e0
modify_qp.isra.7+0xdc4/0x10e0
ib_uverbs_modify_qp+0xfe/0x170
? ib_uverbs_query_qp+0x970/0x970
? __lock_acquire+0xa11/0x1da0
ib_uverbs_write+0x55a/0xad0
? ib_uverbs_query_qp+0x970/0x970
? ib_uverbs_query_qp+0x970/0x970
? ib_uverbs_open+0x760/0x760
? futex_wake+0x147/0x410
? sched_clock_cpu+0x18/0x180
? check_prev_add+0x1680/0x1680
? do_futex+0x3b6/0xa30
? sched_clock_cpu+0x18/0x180
__vfs_write+0xf7/0x5c0
? ib_uverbs_open+0x760/0x760
? kernel_read+0x110/0x110
? lock_acquire+0x370/0x370
? __fget+0x264/0x3b0
vfs_write+0x18a/0x460
SyS_write+0xc7/0x1a0
? SyS_read+0x1a0/0x1a0
? trace_hardirqs_on_thunk+0x1a/0x1c
entry_SYSCALL_64_fastpath+0x18/0x85
RIP: 0033:0x448e29
RSP: 002b:00007f443fee0c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f443fee16bc RCX: 0000000000448e29
RDX: 0000000000000078 RSI: 00000000209f8000 RDI: 0000000000000012
RBP: 000000000070bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000008e98 R14: 00000000006ebf38 R15: 0000000000000000

Allocated by task 1:
kmem_cache_alloc_trace+0x16c/0x2f0
mlx5_alloc_cmd_msg+0x12e/0x670
cmd_exec+0x419/0x1810
mlx5_cmd_exec+0x40/0x70
mlx5_core_mad_ifc+0x187/0x220
mlx5_MAD_IFC+0xd7/0x1b0
mlx5_query_mad_ifc_gids+0x1f3/0x650
mlx5_ib_query_gid+0xa4/0xc0
ib_query_gid+0x152/0x1a0
ib_query_port+0x21e/0x290
mlx5_port_immutable+0x30f/0x490
ib_register_device+0x5dd/0x1130
mlx5_ib_add+0x3e7/0x700
mlx5_add_device+0x124/0x510
mlx5_register_interface+0x11f/0x1c0
mlx5_ib_init+0x56/0x61
do_one_initcall+0xa3/0x250
kernel_init_freeable+0x309/0x3b8
kernel_init+0x14/0x180
ret_from_fork+0x24/0x30

Freed by task 1:
kfree+0xeb/0x2f0
mlx5_free_cmd_msg+0xcd/0x140
cmd_exec+0xeba/0x1810
mlx5_cmd_exec+0x40/0x70
mlx5_core_mad_ifc+0x187/0x220
mlx5_MAD_IFC+0xd7/0x1b0
mlx5_query_mad_ifc_gids+0x1f3/0x650
mlx5_ib_query_gid+0xa4/0xc0
ib_query_gid+0x152/0x1a0
ib_query_port+0x21e/0x290
mlx5_port_immutable+0x30f/0x490
ib_register_device+0x5dd/0x1130
mlx5_ib_add+0x3e7/0x700
mlx5_add_device+0x124/0x510
mlx5_register_interface+0x11f/0x1c0
mlx5_ib_init+0x56/0x61
do_one_initcall+0xa3/0x250
kernel_init_freeable+0x309/0x3b8
kernel_init+0x14/0x180
ret_from_fork+0x24/0x30

The buggy address belongs to the object at ffff88005fda1ab0
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 24 bytes inside of
32-byte region [ffff88005fda1ab0, ffff88005fda1ad0)
The buggy address belongs to the page:
page:00000000d5655c19 count:1 mapcount:0 mapping: (null)
index:0xffff88005fda1fc0
flags: 0x4000000000000100(slab)
raw: 4000000000000100 0000000000000000 ffff88005fda1fc0 0000000180550008
raw: ffffea00017f6780 0000000400000004 ffff88006c803980 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88005fda1980: fc fc fb fb fb fb fc fc fb fb fb fb fc fc fb fb
ffff88005fda1a00: fb fb fc fc fb fb fb fb fc fc 00 00 00 00 fc fc
ffff88005fda1a80: fb fb fb fb fc fc fb fb fb fb fc fc fb fb fb fb
ffff88005fda1b00: fc fc 00 00 00 00 fc fc fb fb fb fb fc fc fb fb
ffff88005fda1b80: fb fb fc fc fb fb fb fb fc fc fb fb fb fb fc fc
==================================================================@

Cc: syzkaller <syzkaller@googlegroups.com>
Cc: <stable@vger.kernel.org> # 4.11
Fixes: 3832125624 ("IB/core: Add support for idr types")
Reported-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-02-15 14:59:47 -07:00
arch unify {de,}mangle_poll(), get rid of kernel-side POLL... 2018-02-11 14:37:22 -08:00
block vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
Documentation KVM changes for 4.16 2018-02-10 13:16:35 -08:00
drivers RDMA/uverbs: Protect from races between lookup and destroy of uobjects 2018-02-15 14:59:47 -07:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
include IB/uverbs: Use __aligned_u64 for uapi headers 2018-02-15 14:59:45 -07:00
init membarrier: Provide core serializing command, *_SYNC_CORE 2018-02-05 21:35:03 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
lib Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
net vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
samples sample/bpf: fix erspan metadata 2018-02-06 11:32:49 -05:00
scripts Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
security vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
sound vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-09 15:34:18 -08:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore scripts/package: snap-pkg target 2017-12-13 00:00:18 +09:00
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS KVM changes for 4.16 2018-02-10 13:16:35 -08:00
Makefile Linux 4.16-rc1 2018-02-11 15:04:29 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.