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Dae R. Jeong d22b2a3572 vmci_host: fix a race condition in vmci_host_poll() causing GPF
[ Upstream commit ae13381da5ff0e8e084c0323c3cc0a945e43e9c7 ]

During fuzzing, a general protection fault is observed in
vmci_host_poll().

general protection fault, probably for non-canonical address 0xdffffc0000000019: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000c8-0x00000000000000cf]
RIP: 0010:__lock_acquire+0xf3/0x5e00 kernel/locking/lockdep.c:4926
<- omitting registers ->
Call Trace:
 <TASK>
 lock_acquire+0x1a4/0x4a0 kernel/locking/lockdep.c:5672
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xb3/0x100 kernel/locking/spinlock.c:162
 add_wait_queue+0x3d/0x260 kernel/sched/wait.c:22
 poll_wait include/linux/poll.h:49 [inline]
 vmci_host_poll+0xf8/0x2b0 drivers/misc/vmw_vmci/vmci_host.c:174
 vfs_poll include/linux/poll.h:88 [inline]
 do_pollfd fs/select.c:873 [inline]
 do_poll fs/select.c:921 [inline]
 do_sys_poll+0xc7c/0x1aa0 fs/select.c:1015
 __do_sys_ppoll fs/select.c:1121 [inline]
 __se_sys_ppoll+0x2cc/0x330 fs/select.c:1101
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4e/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Example thread interleaving that causes the general protection fault
is as follows:

CPU1 (vmci_host_poll)               CPU2 (vmci_host_do_init_context)
-----                               -----
// Read uninitialized context
context = vmci_host_dev->context;
                                    // Initialize context
                                    vmci_host_dev->context = vmci_ctx_create();
                                    vmci_host_dev->ct_type = VMCIOBJ_CONTEXT;

if (vmci_host_dev->ct_type == VMCIOBJ_CONTEXT) {
    // Dereferencing the wrong pointer
    poll_wait(..., &context->host_context);
}

In this scenario, vmci_host_poll() reads vmci_host_dev->context first,
and then reads vmci_host_dev->ct_type to check that
vmci_host_dev->context is initialized. However, since these two reads
are not atomically executed, there is a chance of a race condition as
described above.

To fix this race condition, read vmci_host_dev->context after checking
the value of vmci_host_dev->ct_type so that vmci_host_poll() always
reads an initialized context.

Reported-by: Dae R. Jeong <threeearcat@gmail.com>
Fixes: 8bf503991f ("VMCI: host side driver implementation.")
Signed-off-by: Dae R. Jeong <threeearcat@gmail.com>
Link: https://lore.kernel.org/r/ZCGFsdBAU4cYww5l@dragonet
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-05-11 23:03:28 +09:00
arch arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-step 2023-05-11 23:03:16 +09:00
block blk-mq: don't plug for head insertions in blk_execute_rq_nowait 2023-05-11 23:03:22 +09:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: drbg - Only fail when jent is unavailable in FIPS mode 2023-05-11 23:03:21 +09:00
Documentation ASoC: dt-bindings: qcom,lpass-rx-macro: correct minItems for clocks 2023-05-11 23:03:05 +09:00
drivers vmci_host: fix a race condition in vmci_host_poll() causing GPF 2023-05-11 23:03:28 +09:00
fs pstore: Revert pmsg_lock back to a normal mutex 2023-05-11 23:03:27 +09:00
include linux/vt_buffer.h: allow either builtin or modular for macros 2023-05-11 23:03:28 +09:00
init gcc: disable '-Warray-bounds' for gcc-13 too 2023-04-26 14:28:43 +02:00
io_uring io_uring/rsrc: use nospec'ed indexes 2023-05-11 23:03:24 +09:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel bpf: Don't EFAULT for getsockopt with optval=NULL 2023-05-11 23:03:26 +09:00
lib debugobject: Prevent init race with static objects 2023-05-11 23:03:16 +09:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/mempolicy: fix use-after-free of VMA iterator 2023-05-01 08:26:27 +09:00
net tcp/udp: Fix memleaks of sk and zerocopy skbs with TX timestamp. 2023-05-11 23:03:26 +09:00
rust rust: kernel: Mark rust_fmt_argument as extern "C" 2023-04-26 14:28:38 +02:00
samples ftrace: Export ftrace_free_filter() to modules 2023-02-01 08:34:37 +01:00
scripts ASN.1: Fix check for strdup() success 2023-04-26 14:28:44 +02:00
security selinux: ensure av_permissions.h is built when needed 2023-05-11 23:03:06 +09:00
sound ASoC: es8316: Handle optional IRQ assignment 2023-05-11 23:03:28 +09:00
tools net/sched: sch_fq: fix integer overflow of "credit" 2023-05-11 23:03:26 +09:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Register /dev/kvm as the _very_ last thing during initialization 2023-03-10 09:34:11 +01:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.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 MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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 audit: update the mailing list in MAINTAINERS 2023-02-25 11:25:42 +01:00
Makefile Linux 6.1.27 2023-05-01 08:26:28 +09:00
README

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

There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text 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.