ip6_tunnel: use skb_cow_head() in ip6_tnl_xmit()

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/ipv6/ip6_tunnel.c"
                    ],
                    "versions": [
                        {
                            "version": "058214a4d1dfefed9f01a277fadd3590acb5f990",
                            "lessThan": "6e8eff8ed13b14708bc39f170144eacde494aac6",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "058214a4d1dfefed9f01a277fadd3590acb5f990",
                            "lessThan": "dc1a319a4815c074914e2812e0e9cd0164ca682b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "058214a4d1dfefed9f01a277fadd3590acb5f990",
                            "lessThan": "629d5557e635cdbc109a14ed913ba5a540e3f79a",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "058214a4d1dfefed9f01a277fadd3590acb5f990",
                            "lessThan": "defa0adeff132cc90ed66915b9a104d9393e1e54",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "058214a4d1dfefed9f01a277fadd3590acb5f990",
                            "lessThan": "37df5bc6b5ccad88c2faa0f5466f150178882b74",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "058214a4d1dfefed9f01a277fadd3590acb5f990",
                            "lessThan": "b36dfd6e8cff00cea81c11cc0af88d1564763461",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "058214a4d1dfefed9f01a277fadd3590acb5f990",
                            "lessThan": "8fc56ca49fc0ee1725b55c67bb43ab0dd01f3f52",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "058214a4d1dfefed9f01a277fadd3590acb5f990",
                            "lessThan": "87f21b59ddc618eff9670c174842964ad65fdade",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/ipv6/ip6_tunnel.c"
                    ],
                    "versions": [
                        {
                            "version": "4.7",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.7",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.270",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.221",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.188",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.157",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.109",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.50",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.4",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }