CVE-2024-53187

What it actually does

Missing bounds check on user-supplied uaddr in io_pin_pages allows integer overflow when size is added, leading to incorrect page pinning and potential out-of-bounds memory operations in io_uring.

Why it matters to the business

Local attackers on affected Linux systems may trigger kernel crashes, denial of service, or memory corruption that affects stability and availability of services relying on io_uring.

How an attack unfolds

An attacker invokes io_uring_setup with a crafted user address that overflows when io_pin_pages computes the end address; the kernel proceeds with invalid pinning during ring mapping, enabling further corruption or information disclosure.

How to fix it

Upgrade the Linux kernel to a version containing commit 29eac3eca72d4c2a71122050c37cd7d8f73ac4f3 or later; rebuild and reboot with the patched kernel; disable io_uring via kernel boot parameter if immediate patching is impossible.

How to confirm the fix worked

Verify the running kernel contains commit 29eac3eca72d4c2a71122050c37cd7d8f73ac4f3; attempt to reproduce the original warning with a fuzzer targeting io_pin_pages and confirm the overflow check is present in the binary.

Typical attack path

1. Craft io_uring setup parameters containing an address near the top of the address space
2. Call io_uring_setup to reach io_allocate_scq_urings and io_rings_map
3. Trigger io_pin_pages with the overflowing uaddr
4. Exploit resulting invalid page map for memory corruption or denial of service

How to detect it

Search kernel logs and dmesg for WARNING messages at io_uring/memmap.c:144 or call traces containing io_pin_pages, __io_uaddr_map, and io_allocate_scq_urings; inspect audit logs for unusual io_uring_setup calls from untrusted processes.

• WARNING: CPU:.*io_pin_pages+0x149/0x180
• io_uring/memmap.c:144
• __io_uaddr_map+0xfb/0x2d0
• io_allocate_scq_urings+0x1c0/0x650

What your security team should do

• Apply the referenced kernel commit or distribution update within the next maintenance window
• Restrict unprivileged io_uring use via sysctl or seccomp where feasible
• Monitor kernel logs for io_pin_pages warnings until patches are deployed