{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: vlan: fix underflow for the real_dev refcnt\n\nInject error before dev_hold(real_dev) in register_vlan_dev(),\nand execute the following testcase:\n\nip link add dev dummy1 type dummy\nip link add name dummy1.100 link dummy1 type vlan id 100\nip link del dev dummy1\n\nWhen the dummy netdevice is removed, we will get a WARNING as following:\n\n=======================================================================\nrefcount_t: decrement hit 0; leaking memory.\nWARNING: CPU: 2 PID: 0 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0\n\nand an endless loop of:\n\n=======================================================================\nunregister_netdevice: waiting for dummy1 to become free. Usage count = -1073741824\n\nThat is because dev_put(real_dev) in vlan_dev_free() be called without\ndev_hold(real_dev) in register_vlan_dev(). It makes the refcnt of real_dev\nunderflow.\n\nMove the dev_hold(real_dev) to vlan_dev_init() which is the call-back of\nndo_init(). That makes dev_hold() and dev_put() for vlan's real_dev\nsymmetrical."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "net/8021q/vlan.c",
                  "net/8021q/vlan_dev.c"
               ],
               "versions": [
                  {
                     "version": "700602b662d7",
                     "lessThan": "5e44178864b3",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "e04a7a84bb77",
                     "lessThan": "6e800ee43218",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "21032425c36f",
                     "lessThan": "f7fc72a508cf",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "563bcbae3ba2",
                     "lessThan": "01d9cc2dea3f",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "net/8021q/vlan.c",
                  "net/8021q/vlan_dev.c"
               ],
               "versions": [
                  {
                     "version": "5.4.160",
                     "lessThan": "5.4.163",
                     "status": "affected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.10.80",
                     "lessThan": "5.10.83",
                     "status": "affected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15.3",
                     "lessThan": "5.15.6",
                     "status": "affected",
                     "versionType": "custom"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/5e44178864b38dd70b877985abd7d86fdb95f27d"
            },
            {
               "url": "https://git.kernel.org/stable/c/6e800ee43218a56acc93676bbb3d93b74779e555"
            },
            {
               "url": "https://git.kernel.org/stable/c/f7fc72a508cf115c273a7a29350069def1041890"
            },
            {
               "url": "https://git.kernel.org/stable/c/01d9cc2dea3fde3bad6d27f464eff463496e2b00"
            }
         ],
         "title": "net: vlan: fix underflow for the real_dev refcnt",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2021-47555",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}