Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: net: gro: don't merge zcopy skbs skb_gro_receive() can currently copy frags between the source and GRO skb, without checking the zerocopy status, and in particular the SKBFL_MANAGED_FRAG_REFS flag. When SKBFL_MANAGED_FRAG_REFS is set, the skb doesn't hold a reference on the pages in shinfo->frags. Appending those frags to another skb's frags without fixing up the page refcount can lead to UAF. When either the last skb in the GRO chain (the one we would append frags to) or the source skb is zerocopy, don't merge the skbs.

Affected versions

Linux: 753f1ca4e1e50248a1b760c9774d6d6b354562cc through before 3c6cc9f2ca65b6dd61b1af75452dc0e1cd0aad8d (git); 753f1ca4e1e50248a1b760c9774d6d6b354562cc through before 1f9c828556416fbe3f49386708ce999fc4d4da06 (git); 753f1ca4e1e50248a1b760c9774d6d6b354562cc through before 479084ae0e1d9cb7929cb4298d35623de189f80a (git); 753f1ca4e1e50248a1b760c9774d6d6b354562cc through before e334cbf3388fd9334503a778a82d9e9f14dd2f71 (git); 753f1ca4e1e50248a1b760c9774d6d6b354562cc through before 44bea2032af0425e4ce6d26a8af0ede79db49ec1 (git); 753f1ca4e1e50248a1b760c9774d6d6b354562cc through before 4db79a322db8c97f7b73b8a347395ef4d685eb40 (git); 6.0; V3.1.6 through before * (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.