Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: fix runt reassembly panic from short inner tot_len When the start of an inner packet is split across two outer packets such that fewer than 4 bytes land at the end of the first one, __input_process_payload() saves those bytes as a runt and skips the iplen/iphlen validation performed for in-place packets. When the continuation packet arrives, iptfs_reassem_cont() only requires the declared inner length to be >= sizeof(ra_runt) (6) before allocating the reassembly skb with that attacker-controlled length. However, __iptfs_iphlen() always returns the fixed minimum IP header size (20 for IPv4, 40 for IPv6), so for an inner IPv4 tot_len in [6, 19] the header-completion copy writes past the declared packet length, and the subsequent "ipremain -= copylen" underflows to ~4GB, leaving the payload copy length bounded only by blkoff (up to 64KB). At runtime the skb_put() tailroom check turns this into skb_over_panic(), i.e. an unprivileged kernel panic (DoS), reachable locally via userns+netns IPTFS SAs and remotely against IPTFS VPN gateways when the decrypted outer skb is linear (e.g. AF_PACKET taps, tun/tap delivery). Align the runt path with the normal path by requiring the declared inner length to cover at least the IP header size. This also subsumes the previous >= sizeof(ra_runt) check, since the minimum IP header is always larger than the runt buffer. This issue was found by the autokbug dynamic kernel fuzzer at Tencent Yunding Lab.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 07569476544681816335099929ff3494dfbf6b05 before a7018ee0ea8622ed59edc064be4e0f2c26464f53; affected 07569476544681816335099929ff3494dfbf6b05 before 5b8afb56ccb7c014b0f1ac40341708b200443c2d; affected 07569476544681816335099929ff3494dfbf6b05 before dc33262be1fe43d0eb0b84fb58c6ed42e2f64a8c |
| Linux / Linux | affected 6.14; unaffected 0 before 6.14; unaffected 6.18.54 through 6.18.*; unaffected 7.2.8 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.