CVE-2024-50163
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Make sure internal and UAPI bpf_redirect flags don't overlap The bpf_redirect_info is shared between the SKB and XDP redirect paths, and the two paths use the same numeric flag values in the ri->flags field (specifically, BPF_F_BROADCAST == BPF_F_NEXTHOP). This means that if skb bpf_redirect_neigh() is used with a non-NULL params argument and, subsequently, an XDP redirect is performed using the same bpf_redirect_info struct, the XDP path will get confused and end up crashing, which syzbot managed to trigger. With the stack-allocated bpf_redirect_info, the structure is no longer shared between the SKB and XDP paths, so the crash doesn't happen anymore. However, different code paths using identically-numbered flag values in the same struct field still seems like a bit of a mess, so this patch cleans that up by moving the flag definitions together and redefining the three flags in BPF_F_REDIRECT_INTERNAL to not overlap with the flags used for XDP. It also adds a BUILD_BUG_ON() check to make sure the overlap is not re-introduced by mistake.
How to fix
- linux linux_kernel5.15.170, 6.1.115, 6.6.59, 6.11.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 5.14 ≤ v < 5.15.170, 5.16 ≤ v < 6.1.115, 6.2 ≤ v < 6.6.59, 6.7 ≤ v < 6.11.6, 6.12 | 5.15.170, 6.1.115, 6.6.59, 6.11.6 |
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