FKIE_CVE-2022-50816

Vulnerability from fkie_nvd - Published: 2025-12-30 13:15 - Updated: 2025-12-31 20:43
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: ensure sane device mtu in tunnels Another syzbot report [1] with no reproducer hints at a bug in ip6_gre tunnel (dev:ip6gretap0) Since ipv6 mcast code makes sure to read dev->mtu once and applies a sanity check on it (see commit b9b312a7a451 "ipv6: mcast: better catch silly mtu values"), a remaining possibility is that a layer is able to set dev->mtu to an underflowed value (high order bit set). This could happen indeed in ip6gre_tnl_link_config_route(), ip6_tnl_link_config() and ipip6_tunnel_bind_dev() Make sure to sanitize mtu value in a local variable before it is written once on dev->mtu, as lockless readers could catch wrong temporary value. [1] skbuff: skb_over_panic: text:ffff80000b7a2f38 len:40 put:40 head:ffff000149dcf200 data:ffff000149dcf2b0 tail:0xd8 end:0xc0 dev:ip6gretap0 ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:120 Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 10241 Comm: kworker/1:1 Not tainted 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022 Workqueue: mld mld_ifc_work pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : skb_panic+0x4c/0x50 net/core/skbuff.c:116 lr : skb_panic+0x4c/0x50 net/core/skbuff.c:116 sp : ffff800020dd3b60 x29: ffff800020dd3b70 x28: 0000000000000000 x27: ffff00010df2a800 x26: 00000000000000c0 x25: 00000000000000b0 x24: ffff000149dcf200 x23: 00000000000000c0 x22: 00000000000000d8 x21: ffff80000b7a2f38 x20: ffff00014c2f7800 x19: 0000000000000028 x18: 00000000000001a9 x17: 0000000000000000 x16: ffff80000db49158 x15: ffff000113bf1a80 x14: 0000000000000000 x13: 00000000ffffffff x12: ffff000113bf1a80 x11: ff808000081c0d5c x10: 0000000000000000 x9 : 73f125dc5c63ba00 x8 : 73f125dc5c63ba00 x7 : ffff800008161d1c x6 : 0000000000000000 x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000 x2 : ffff0001fefddcd0 x1 : 0000000100000000 x0 : 0000000000000089 Call trace: skb_panic+0x4c/0x50 net/core/skbuff.c:116 skb_over_panic net/core/skbuff.c:125 [inline] skb_put+0xd4/0xdc net/core/skbuff.c:2049 ip6_mc_hdr net/ipv6/mcast.c:1714 [inline] mld_newpack+0x14c/0x270 net/ipv6/mcast.c:1765 add_grhead net/ipv6/mcast.c:1851 [inline] add_grec+0xa20/0xae0 net/ipv6/mcast.c:1989 mld_send_cr+0x438/0x5a8 net/ipv6/mcast.c:2115 mld_ifc_work+0x38/0x290 net/ipv6/mcast.c:2653 process_one_work+0x2d8/0x504 kernel/workqueue.c:2289 worker_thread+0x340/0x610 kernel/workqueue.c:2436 kthread+0x12c/0x158 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 Code: 91011400 aa0803e1 a90027ea 94373093 (d4210000)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2bab6fa449d16af36d9c9518865f783a15f446c7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/44affe7ede596f078c4f2f41e0d160266ccda818
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/78297d513157a31fd629626fe4cbb85a7dcbb94a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ad3f1d9bf162c487d23df684852597961b745cae
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/af51fc23a03f02b0c6df09ab0d60f23794436052
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ccd94bd4939690e24d13e23814bce7ed853a09f3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d89d7ff01235f218dad37de84457717f699dee79
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: ensure sane device mtu in tunnels\n\nAnother syzbot report [1] with no reproducer hints\nat a bug in ip6_gre tunnel (dev:ip6gretap0)\n\nSince ipv6 mcast code makes sure to read dev-\u003emtu once\nand applies a sanity check on it (see commit b9b312a7a451\n\"ipv6: mcast: better catch silly mtu values\"), a remaining\npossibility is that a layer is able to set dev-\u003emtu to\nan underflowed value (high order bit set).\n\nThis could happen indeed in ip6gre_tnl_link_config_route(),\nip6_tnl_link_config() and ipip6_tunnel_bind_dev()\n\nMake sure to sanitize mtu value in a local variable before\nit is written once on dev-\u003emtu, as lockless readers could\ncatch wrong temporary value.\n\n[1]\nskbuff: skb_over_panic: text:ffff80000b7a2f38 len:40 put:40 head:ffff000149dcf200 data:ffff000149dcf2b0 tail:0xd8 end:0xc0 dev:ip6gretap0\n------------[ cut here ]------------\nkernel BUG at net/core/skbuff.c:120\nInternal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP\nModules linked in:\nCPU: 1 PID: 10241 Comm: kworker/1:1 Not tainted 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022\nWorkqueue: mld mld_ifc_work\npstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : skb_panic+0x4c/0x50 net/core/skbuff.c:116\nlr : skb_panic+0x4c/0x50 net/core/skbuff.c:116\nsp : ffff800020dd3b60\nx29: ffff800020dd3b70 x28: 0000000000000000 x27: ffff00010df2a800\nx26: 00000000000000c0 x25: 00000000000000b0 x24: ffff000149dcf200\nx23: 00000000000000c0 x22: 00000000000000d8 x21: ffff80000b7a2f38\nx20: ffff00014c2f7800 x19: 0000000000000028 x18: 00000000000001a9\nx17: 0000000000000000 x16: ffff80000db49158 x15: ffff000113bf1a80\nx14: 0000000000000000 x13: 00000000ffffffff x12: ffff000113bf1a80\nx11: ff808000081c0d5c x10: 0000000000000000 x9 : 73f125dc5c63ba00\nx8 : 73f125dc5c63ba00 x7 : ffff800008161d1c x6 : 0000000000000000\nx5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000\nx2 : ffff0001fefddcd0 x1 : 0000000100000000 x0 : 0000000000000089\nCall trace:\nskb_panic+0x4c/0x50 net/core/skbuff.c:116\nskb_over_panic net/core/skbuff.c:125 [inline]\nskb_put+0xd4/0xdc net/core/skbuff.c:2049\nip6_mc_hdr net/ipv6/mcast.c:1714 [inline]\nmld_newpack+0x14c/0x270 net/ipv6/mcast.c:1765\nadd_grhead net/ipv6/mcast.c:1851 [inline]\nadd_grec+0xa20/0xae0 net/ipv6/mcast.c:1989\nmld_send_cr+0x438/0x5a8 net/ipv6/mcast.c:2115\nmld_ifc_work+0x38/0x290 net/ipv6/mcast.c:2653\nprocess_one_work+0x2d8/0x504 kernel/workqueue.c:2289\nworker_thread+0x340/0x610 kernel/workqueue.c:2436\nkthread+0x12c/0x158 kernel/kthread.c:376\nret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860\nCode: 91011400 aa0803e1 a90027ea 94373093 (d4210000)"
    }
  ],
  "id": "CVE-2022-50816",
  "lastModified": "2025-12-31T20:43:05.160",
  "metrics": {},
  "published": "2025-12-30T13:15:55.963",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2bab6fa449d16af36d9c9518865f783a15f446c7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/44affe7ede596f078c4f2f41e0d160266ccda818"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/78297d513157a31fd629626fe4cbb85a7dcbb94a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ad3f1d9bf162c487d23df684852597961b745cae"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/af51fc23a03f02b0c6df09ab0d60f23794436052"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ccd94bd4939690e24d13e23814bce7ed853a09f3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d89d7ff01235f218dad37de84457717f699dee79"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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