Entreprise française de cybersécurité depuis 2004
☎ 03 60 47 09 81 - info@securiteinfo.com
☎ 03 60 47 09 81 - info@securiteinfo.com
In the Linux kernel, the following vulnerability has been resolved:bpf: Make sure internal and UAPI bpf_redirect flags don't overlapThe 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->flagsfield (specifically, BPF_F_BROADCAST == BPF_F_NEXTHOP). This means thatif skb bpf_redirect_neigh() is used with a non-NULL params argument and,subsequently, an XDP redirect is performed using the samebpf_redirect_info struct, the XDP path will get confused and end upcrashing, which syzbot managed to trigger.With the stack-allocated bpf_redirect_info, the structure is no longershared between the SKB and XDP paths, so the crash doesn't happenanymore. However, different code paths using identically-numbered flagvalues in the same struct field still seems like a bit of a mess, sothis patch cleans that up by moving the flag definitions together andredefining the three flags in BPF_F_REDIRECT_INTERNAL to not overlapwith the flags used for XDP. It also adds a BUILD_BUG_ON() check to makesure the overlap is not re-introduced by mistake.
No PoCs from references.
- https://github.com/ARPSyndicate/cve-scores