发布于3月6日3月6日 Members Amazon Linux 2023: CVE-2023-52828: Important priority package update for kernel Severity 5 CVSS (AV:L/AC:L/Au:S/C:N/I:N/A:C) Published 05/21/2024 Created 02/14/2025 Added 02/14/2025 Modified 02/14/2025 Description In the Linux kernel, the following vulnerability has been resolved: bpf: Detect IP == ksym.end as part of BPF program Now that bpf_throw kfunc is the first such call instruction that has noreturn semantics within the verifier, this also kicks in dead code elimination in unprecedented ways. For one, any instruction following a bpf_throw call will never be marked as seen. Moreover, if a callchain ends up throwing, any instructions after the call instruction to the eventually throwing subprog in callers will also never be marked as seen. The tempting way to fix this would be to emit extra 'int3' instructions which bump the jited_len of a program, and ensure that during runtime when a program throws, we can discover its boundaries even if the call instruction to bpf_throw (or to subprogs that always throw) is emitted as the final instruction in the program. An example of such a program would be this: do_something(): ... r0 = 0 exit foo(): r1 = 0 call bpf_throw r0 = 0 exit bar(cond): if r1 != 0 goto pc+2 call do_something exit call foo r0 = 0// Never seen by verifier exit// main(ctx): r1 = ... call bar r0 = 0 exit Here, if we do end up throwing, the stacktrace would be the following: bpf_throw foo bar main In bar, the final instruction emitted will be the call to foo, as such, the return address will be the subsequent instruction (which the JIT emits as int3 on x86). This will end up lying outside the jited_len of the program, thus, when unwinding, we will fail to discover the return address as belonging to any program and end up in a panic due to the unreliable stack unwinding of BPF programs that we never expect. To remedy this case, make bpf_prog_ksym_find treat IP == ksym.end as part of the BPF program, so that is_bpf_text_address returns true when such a case occurs, and we are able to unwind reliably when the final instruction ends up being a call instruction. Solution(s) amazon-linux-2023-upgrade-bpftool amazon-linux-2023-upgrade-bpftool-debuginfo amazon-linux-2023-upgrade-kernel amazon-linux-2023-upgrade-kernel-debuginfo amazon-linux-2023-upgrade-kernel-debuginfo-common-aarch64 amazon-linux-2023-upgrade-kernel-debuginfo-common-x86-64 amazon-linux-2023-upgrade-kernel-devel amazon-linux-2023-upgrade-kernel-headers amazon-linux-2023-upgrade-kernel-libbpf amazon-linux-2023-upgrade-kernel-libbpf-devel amazon-linux-2023-upgrade-kernel-libbpf-static amazon-linux-2023-upgrade-kernel-livepatch-6-1-66-91-160 amazon-linux-2023-upgrade-kernel-modules-extra amazon-linux-2023-upgrade-kernel-tools amazon-linux-2023-upgrade-kernel-tools-debuginfo amazon-linux-2023-upgrade-kernel-tools-devel amazon-linux-2023-upgrade-perf amazon-linux-2023-upgrade-perf-debuginfo amazon-linux-2023-upgrade-python3-perf amazon-linux-2023-upgrade-python3-perf-debuginfo References https://attackerkb.com/topics/cve-2023-52828 CVE - 2023-52828 https://alas.aws.amazon.com/AL2023/ALAS-2023-461.html
