CVE-2024-43840

/// Technical description

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

bpf, arm64: Fix trampoline for BPF_TRAMP_F_CALL_ORIG

When BPF_TRAMP_F_CALL_ORIG is set, the trampoline calls

__bpf_tramp_enter() and __bpf_tramp_exit() functions, passing them

the struct bpf_tramp_image *im pointer as an argument in R0.

The trampoline generation code uses emit_addr_mov_i64() to emit

instructions for moving the bpf_tramp_image address into R0, but

emit_addr_mov_i64() assumes the address to be in the vmalloc() space

and uses only 48 bits. Because bpf_tramp_image is allocated using

kzalloc(), its address can use more than 48-bits, in this case the

trampoline will pass an invalid address to __bpf_tramp_enter/exit()

causing a kernel crash.

Fix this by using emit_a64_mov_i64() in place of emit_addr_mov_i64()

as it can work with addresses that are greater than 48-bits.

/// 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