{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nseg6: fix the iif in the IPv6 socket control block\n\nWhen an IPv4 packet is received, the ip_rcv_core(...) sets the receiving\ninterface index into the IPv4 socket control block (v5.16-rc4,\nnet/ipv4/ip_input.c line 510):\n\n    IPCB(skb)->iif = skb->skb_iif;\n\nIf that IPv4 packet is meant to be encapsulated in an outer IPv6+SRH\nheader, the seg6_do_srh_encap(...) performs the required encapsulation.\nIn this case, the seg6_do_srh_encap function clears the IPv6 socket control\nblock (v5.16-rc4 net/ipv6/seg6_iptunnel.c line 163):\n\n    memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));\n\nThe memset(...) was introduced in commit ef489749aae5 (\"ipv6: sr: clear\nIP6CB(skb) on SRH ip4ip6 encapsulation\") a long time ago (2019-01-29).\n\nSince the IPv6 socket control block and the IPv4 socket control block share\nthe same memory area (skb->cb), the receiving interface index info is lost\n(IP6CB(skb)->iif is set to zero).\n\nAs a side effect, that condition triggers a NULL pointer dereference if\ncommit 0857d6f8c759 (\"ipv6: When forwarding count rx stats on the orig\nnetdev\") is applied.\n\nTo fix that issue, we set the IP6CB(skb)->iif with the index of the\nreceiving interface once again."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "net/ipv6/seg6_iptunnel.c"
               ],
               "versions": [
                  {
                     "version": "c630ec8bdada",
                     "lessThan": "b16d412e5f79",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "2f704348c93f",
                     "lessThan": "6431e71093f3",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ef489749aae5",
                     "lessThan": "ef8804e47c0a",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ef489749aae5",
                     "lessThan": "666521b3852d",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ef489749aae5",
                     "lessThan": "98adb2bbfa40",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ef489749aae5",
                     "lessThan": "ae68d93354e5",
                     "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/seg6_iptunnel.c"
               ],
               "versions": [
                  {
                     "version": "5.0",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "5.0",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "4.14.258",
                     "lessThanOrEqual": "4.14.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "4.19.221",
                     "lessThanOrEqual": "4.19.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.4.165",
                     "lessThanOrEqual": "5.4.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.10.85",
                     "lessThanOrEqual": "5.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15.8",
                     "lessThanOrEqual": "5.15.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.16",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3"
            },
            {
               "url": "https://git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e"
            },
            {
               "url": "https://git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9"
            },
            {
               "url": "https://git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831"
            },
            {
               "url": "https://git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1"
            },
            {
               "url": "https://git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c"
            }
         ],
         "title": "seg6: fix the iif in the IPv6 socket control block",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2021-47515",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}