CVE-2024-50163

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> bpf: Make sure internal and UAPI bpf_redirect flags don&amp;#39;t overlap<br /> <br /> The bpf_redirect_info is shared between the SKB and XDP redirect paths,<br /> and the two paths use the same numeric flag values in the ri-&gt;flags<br /> field (specifically, BPF_F_BROADCAST == BPF_F_NEXTHOP). This means that<br /> if skb bpf_redirect_neigh() is used with a non-NULL params argument and,<br /> subsequently, an XDP redirect is performed using the same<br /> bpf_redirect_info struct, the XDP path will get confused and end up<br /> crashing, which syzbot managed to trigger.<br /> <br /> With the stack-allocated bpf_redirect_info, the structure is no longer<br /> shared between the SKB and XDP paths, so the crash doesn&amp;#39;t happen<br /> anymore. However, different code paths using identically-numbered flag<br /> values in the same struct field still seems like a bit of a mess, so<br /> this patch cleans that up by moving the flag definitions together and<br /> redefining the three flags in BPF_F_REDIRECT_INTERNAL to not overlap<br /> with the flags used for XDP. It also adds a BUILD_BUG_ON() check to make<br /> sure the overlap is not re-introduced by mistake.