From: Zhengchuan Liang <zcliangcn@gmail.com> mainline inclusion from mainline-v7.1-rc1 commit fdce0b3590f724540795b874b4c8850c90e6b0a8 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14432 CVE: CVE-2026-31685 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- `eui64_mt6()` derives a modified EUI-64 from the Ethernet source address and compares it with the low 64 bits of the IPv6 source address. The existing guard only rejects an invalid MAC header when `par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()` can still reach `eth_hdr(skb)` even when the MAC header is not valid. Fix this by removing the `par->fragoff != 0` condition so that packets with an invalid MAC header are rejected before accessing `eth_hdr(skb)`. Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2") Reported-by: Yifan Wu <yifanwucs@gmail.com> Reported-by: Juefei Pu <tomapufckgml@gmail.com> Co-developed-by: Yuan Tan <yuantan098@gmail.com> Signed-off-by: Yuan Tan <yuantan098@gmail.com> Suggested-by: Xin Liu <bird@lzu.edu.cn> Tested-by: Ren Wei <enjou1224z@gmail.com> Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/ipv6/netfilter/ip6t_eui64.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv6/netfilter/ip6t_eui64.c b/net/ipv6/netfilter/ip6t_eui64.c index aab0706908c5..cda3d43e527d 100644 --- a/net/ipv6/netfilter/ip6t_eui64.c +++ b/net/ipv6/netfilter/ip6t_eui64.c @@ -25,8 +25,7 @@ eui64_mt6(const struct sk_buff *skb, struct xt_action_param *par) unsigned char eui64[8]; if (!(skb_mac_header(skb) >= skb->head && - skb_mac_header(skb) + ETH_HLEN <= skb->data) && - par->fragoff != 0) { + skb_mac_header(skb) + ETH_HLEN <= skb->data)) { par->hotdrop = true; return false; } -- 2.43.0