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Gui-Dong Han c8e0fb0da8 usb: mon: Fix atomicity violation in mon_bin_vma_fault
commit 2dd23cc4d0 upstream.

In mon_bin_vma_fault():
    offset = vmf->pgoff << PAGE_SHIFT;
    if (offset >= rp->b_size)
        return VM_FAULT_SIGBUS;
    chunk_idx = offset / CHUNK_SIZE;
    pageptr = rp->b_vec[chunk_idx].pg;
The code is executed without holding any lock.

In mon_bin_vma_close():
    spin_lock_irqsave(&rp->b_lock, flags);
    rp->mmap_active--;
    spin_unlock_irqrestore(&rp->b_lock, flags);

In mon_bin_ioctl():
    spin_lock_irqsave(&rp->b_lock, flags);
    if (rp->mmap_active) {
        ...
    } else {
        ...
        kfree(rp->b_vec);
        rp->b_vec  = vec;
        rp->b_size = size;
        ...
    }
    spin_unlock_irqrestore(&rp->b_lock, flags);

Concurrent execution of mon_bin_vma_fault() with mon_bin_vma_close() and
mon_bin_ioctl() could lead to atomicity violations. mon_bin_vma_fault()
accesses rp->b_size and rp->b_vec without locking, risking array
out-of-bounds access or use-after-free bugs due to possible modifications
in mon_bin_ioctl().

This possible bug is found by an experimental static analysis tool
developed by our team, BassCheck[1]. This tool analyzes the locking APIs
to extract function pairs that can be concurrently executed, and then
analyzes the instructions in the paired functions to identify possible
concurrency bugs including data races and atomicity violations. The above
possible bug is reported when our tool analyzes the source code of
Linux 6.2.

To address this issue, it is proposed to add a spin lock pair in
mon_bin_vma_fault() to ensure atomicity. With this patch applied, our tool
never reports the possible bug, with the kernel configuration allyesconfig
for x86_64. Due to the lack of associated hardware, we cannot test the
patch in runtime testing, and just verify it according to the code logic.

[1] https://sites.google.com/view/basscheck/

Fixes: 19e6317d24 ("usb: mon: Fix a deadlock in usbmon between ...")
Cc:  <stable@vger.kernel.org>
Signed-off-by: Gui-Dong Han <2045gemini@gmail.com>
Link: https://lore.kernel.org/r/20240105052412.9377-1-2045gemini@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-25 15:35:43 -08:00
arch powerpc/64s: Increase default stack size to 32KB 2024-01-25 15:35:42 -08:00
block blk-cgroup: fix rcu lockdep warning in blkg_lookup() 2024-01-25 15:35:30 -08:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: scomp - fix req->dst buffer overflow 2024-01-25 15:35:18 -08:00
Documentation media: dt-bindings: media: rkisp1: Fix the port description for the parallel interface 2024-01-25 15:35:35 -08:00
drivers usb: mon: Fix atomicity violation in mon_bin_vma_fault 2024-01-25 15:35:43 -08:00
fs Revert "kernfs: convert kernfs_idr_lock to an irq safe raw spinlock" 2024-01-25 15:35:41 -08:00
include gpiolib: provide gpio_device_find() 2024-01-25 15:35:39 -08:00
init proc: sysctl: prevent aliased sysctls from getting passed to init 2023-11-28 17:19:57 +00:00
io_uring io_uring: use fget/fput consistently 2024-01-20 11:51:38 +01:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel tick-sched: Fix idle and iowait sleeptime accounting vs CPU hotplug 2024-01-25 15:35:42 -08:00
lib kunit: debugfs: Fix unchecked dereference in debugfs_print_results() 2024-01-25 15:35:15 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/memory_hotplug: fix memmap_on_memory sysfs value retrieval 2024-01-20 11:51:49 +01:00
net keys, dns: Fix size check of V1 server-list header 2024-01-25 15:35:41 -08:00
rust rust: Ignore preserve-most functions 2024-01-25 15:35:41 -08:00
samples vfio/mtty: Overhaul mtty interrupt handling 2024-01-10 17:16:55 +01:00
scripts scripts/decode_stacktrace.sh: optionally use LLVM utilities 2024-01-20 11:51:49 +01:00
security selinux: Fix error priority for bind with AF_UNSPEC on PF_INET6 socket 2024-01-25 15:35:15 -08:00
sound ALSA: scarlett2: Add clamp() in scarlett2_mixer_ctl_put() 2024-01-25 15:35:39 -08:00
tools selftests/bpf: Add assert for user stacks in test_task_stack 2024-01-25 15:35:41 -08:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 Char/Misc driver fixes for 6.6-final 2023-10-28 07:51:27 -10:00
Makefile Linux 6.6.13 2024-01-20 11:51:49 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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 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.