CVE-2023-52621

/// Technical description

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

bpf: Check rcu_read_lock_trace_held() before calling bpf map helpers

These three bpf_map_{lookup,update,delete}_elem() helpers are also

available for sleepable bpf program, so add the corresponding lock

assertion for sleepable bpf program, otherwise the following warning

will be reported when a sleepable bpf program manipulates bpf map under

interpreter mode (aka bpf_jit_enable=0):

WARNING: CPU: 3 PID: 4985 at kernel/bpf/helpers.c:40 ......

CPU: 3 PID: 4985 Comm: test_progs Not tainted 6.6.0+ #2

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ......

RIP: 0010:bpf_map_lookup_elem+0x54/0x60

......

Call Trace:

<TASK>

? __warn+0xa5/0x240

? bpf_map_lookup_elem+0x54/0x60

? report_bug+0x1ba/0x1f0

? handle_bug+0x40/0x80

? exc_invalid_op+0x18/0x50

? asm_exc_invalid_op+0x1b/0x20

? __pfx_bpf_map_lookup_elem+0x10/0x10

? rcu_lockdep_current_cpu_online+0x65/0xb0

? rcu_is_watching+0x

/// 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