CVE-2021-47376

/// Technical description

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

bpf: Add oversize check before call kvcalloc()

Commit 7661809d493b ("mm: don't allow oversized kvmalloc() calls") add the

oversize check. When the allocation is larger than what kmalloc() supports,

the following warning triggered:

WARNING: CPU: 0 PID: 8408 at mm/util.c:597 kvmalloc_node+0x108/0x110 mm/util.c:597

Modules linked in:

CPU: 0 PID: 8408 Comm: syz-executor221 Not tainted 5.14.0-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

RIP: 0010:kvmalloc_node+0x108/0x110 mm/util.c:597

Call Trace:

kvmalloc include/linux/mm.h:806 [inline]

kvmalloc_array include/linux/mm.h:824 [inline]

kvcalloc include/linux/mm.h:829 [inline]

check_btf_line kernel/bpf/verifier.c:9925 [inline]

check_btf_info kernel/bpf/verifier.c:10049 [inline]

bpf_check+0xd634/0x150d0 kernel/bpf/verifier.c:13759

bpf_prog_load kernel/bpf/syscall.c:2301 [inline]

__sys_bpf+0x11181/0x126e0 kerne

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References