Bug 2424887 (CVE-2025-68363)
| Summary: | CVE-2025-68363 kernel: bpf: Check skb->transport_header is set in bpf_skb_check_mtu | ||
|---|---|---|---|
| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | low | Docs Contact: | |
| Priority: | low | ||
| Version: | unspecified | Keywords: | Security |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
In the Linux kernel, the following vulnerability has been resolved: bpf: Check skb->transport_header is set in bpf_skb_check_mtu The bpf_skb_check_mtu helper needs to use skb->transport_header when the BPF_MTU_CHK_SEGS flag is used: bpf_skb_check_mtu(skb, ifindex, &mtu_len, 0, BPF_MTU_CHK_SEGS) The transport_header is not always set. There is a WARN_ON_ONCE report when CONFIG_DEBUG_NET is enabled + skb->gso_size is set + bpf_prog_test_run is used: WARNING: CPU: 1 PID: 2216 at ./include/linux/skbuff.h:3071 skb_gso_validate_network_len bpf_skb_check_mtu bpf_prog_3920e25740a41171_tc_chk_segs_flag # A test in the next patch bpf_test_run bpf_prog_test_run_skb For a normal ingress skb (not test_run), skb_reset_transport_header is performed but there is plan to avoid setting it as described in commit 2170a1f09148 ("net: no longer reset transport_header in __netif_receive_skb_core()"). This patch fixes the bpf helper by checking skb_transport_header_was_set(). The check is done just before skb->transport_header is used, to avoid breaking the existing bpf prog. The WARN_ON_ONCE is limited to bpf_prog_test_run, so targeting bpf-next.