CVE-2024-39509

In the Linux kernel, the following vulnerability has been resolved:

HID: core: remove unnecessary WARN_ON() in implement()

Syzkaller hit a warning [1] in a call to implement() when trying to write a value into a field of smaller size in an output report.

Since implement() already has a warn message printed out with the help of hid_warn() and value in question gets trimmed with: … value &= m; … WARN_ON may be considered superfluous. Remove it to suppress future syzkaller triggers.

[1] WARNING: CPU: 0 PID: 5084 at drivers/hid/hid-core.c:1451 implement drivers/hid/hid-core.c:1451 [inline] WARNING: CPU: 0 PID: 5084 at drivers/hid/hid-core.c:1451 hid_output_report+0x548/0x760 drivers/hid/hid-core.c:1863 Modules linked in: CPU: 0 PID: 5084 Comm: syz-executor424 Not tainted 6.9.0-rc7-syzkaller-00183-gcf87f46fd34d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:implement drivers/hid/hid-core.c:1451 [inline] RIP: 0010:hid_output_report+0x548/0x760 drivers/hid/hid-core.c:1863 … Call Trace: __usbhid_submit_report drivers/hid/usbhid/hid-core.c:591 [inline] usbhid_submit_report+0x43d/0x9e0 drivers/hid/usbhid/hid-core.c:636 hiddev_ioctl+0x138b/0x1f00 drivers/hid/usbhid/hiddev.c:726 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f …

Weakness

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

Affected Software

Extended Description

While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.

Potential Mitigations

References

• https://git.kernel.org/stable/c/30f76bc468b9b2cbbd5d3eb482661e3e4798893f
• https://git.kernel.org/stable/c/33f6832798dd3297317901cc1db556ac3ae80c24
• https://git.kernel.org/stable/c/4aa2dcfbad538adf7becd0034a3754e1bd01b2b5
• https://git.kernel.org/stable/c/655c6de2f215b61d0708db6b06305eee9bbfeba2
• https://git.kernel.org/stable/c/8bac61934cd563b073cd30b8cf6d5c758ab5ab26
• https://git.kernel.org/stable/c/955b3764671f3f157215194972d9c01a3a4bd316
• https://git.kernel.org/stable/c/bfd546fc7fd76076f81bf41b85b51ceda30949fd
• https://git.kernel.org/stable/c/f9db5fbeffb951cac3f0fb1c2eeffb79785399ca
• https://git.kernel.org/stable/c/30f76bc468b9b2cbbd5d3eb482661e3e4798893f
• https://git.kernel.org/stable/c/33f6832798dd3297317901cc1db556ac3ae80c24
• https://git.kernel.org/stable/c/4aa2dcfbad538adf7becd0034a3754e1bd01b2b5
• https://git.kernel.org/stable/c/655c6de2f215b61d0708db6b06305eee9bbfeba2
• https://git.kernel.org/stable/c/8bac61934cd563b073cd30b8cf6d5c758ab5ab26
• https://git.kernel.org/stable/c/955b3764671f3f157215194972d9c01a3a4bd316
• https://git.kernel.org/stable/c/bfd546fc7fd76076f81bf41b85b51ceda30949fd
• https://git.kernel.org/stable/c/f9db5fbeffb951cac3f0fb1c2eeffb79785399ca