Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: fix pedit partial COW leading to page cache corruption tcf_pedit_act() computes the COW range for skb_ensure_writable() once before the key loop using tcfp_off_max_hint, but the hint does not account for the runtime header offset added by typed keys. This can leave part of the write region un-COW'd. Fix by moving skb_ensure_writable() inside the per-key loop where the actual write offset is known, and add overflow checking on the offset arithmetic. For negative offsets (e.g. Ethernet header edits at ingress), use skb_cow() to COW the headroom instead. Guard offset_valid() against INT_MIN, where negation is undefined.

References 4

• git.kernel.org https://git.kernel.org/stable/c/2bec122b9fb91507a758ab5e3e5c4fbe7cb3f61b
• git.kernel.org https://git.kernel.org/stable/c/3dee9d0c198faeb95d052c1b94c2958751a28512
• git.kernel.org https://git.kernel.org/stable/c/899ee91156e57784090c5565e4f31bd7dbffbc5a
• git.kernel.org https://git.kernel.org/stable/c/b198ed4e52580a7238c7c7082f03906f8b310313

Remediation