ghsa-6vr7-3j3q-8546
Vulnerability from github
Published
2024-02-20 21:30
Modified
2024-09-04 12:30
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Details

In the Linux kernel, the following vulnerability has been resolved:

net: prevent mss overflow in skb_segment()

Once again syzbot is able to crash the kernel in skb_segment() [1]

GSO_BY_FRAGS is a forbidden value, but unfortunately the following computation in skb_segment() can reach it quite easily :

mss = mss * partial_segs;

65535 = 3 * 5 * 17 * 257, so many initial values of mss can lead to a bad final result.

Make sure to limit segmentation so that the new mss value is smaller than GSO_BY_FRAGS.

[1]

general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077] CPU: 1 PID: 5079 Comm: syz-executor993 Not tainted 6.7.0-rc4-syzkaller-00141-g1ae4cd3cbdd0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 RIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551 Code: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00 RSP: 0018:ffffc900043473d0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597 RDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070 RBP: ffffc90004347578 R08: 0000000000000005 R09: 000000000000ffff R10: 000000000000ffff R11: 0000000000000002 R12: ffff888063202ac0 R13: 0000000000010000 R14: 000000000000ffff R15: 0000000000000046 FS: 0000555556e7e380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020010000 CR3: 0000000027ee2000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: udp6_ufo_fragment+0xa0e/0xd00 net/ipv6/udp_offload.c:109 ipv6_gso_segment+0x534/0x17e0 net/ipv6/ip6_offload.c:120 skb_mac_gso_segment+0x290/0x610 net/core/gso.c:53 __skb_gso_segment+0x339/0x710 net/core/gso.c:124 skb_gso_segment include/net/gso.h:83 [inline] validate_xmit_skb+0x36c/0xeb0 net/core/dev.c:3626 __dev_queue_xmit+0x6f3/0x3d60 net/core/dev.c:4338 dev_queue_xmit include/linux/netdevice.h:3134 [inline] packet_xmit+0x257/0x380 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3087 [inline] packet_sendmsg+0x24c6/0x5220 net/packet/af_packet.c:3119 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0xd5/0x180 net/socket.c:745 __sys_sendto+0x255/0x340 net/socket.c:2190 __do_sys_sendto net/socket.c:2202 [inline] __se_sys_sendto net/socket.c:2198 [inline] __x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f8692032aa9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff8d685418 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8692032aa9 RDX: 0000000000010048 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00000000000f4240 R08: 0000000020000540 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff8d685480 R13: 0000000000000001 R14: 00007fff8d685480 R15: 0000000000000003 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551 Code: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00 RSP: 0018:ffffc900043473d0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597 RDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070 RBP: ffffc90004347578 R0 ---truncated---

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{
  "affected": [],
  "aliases": [
    "CVE-2023-52435"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-119"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-02-20T20:15:08Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: prevent mss overflow in skb_segment()\n\nOnce again syzbot is able to crash the kernel in skb_segment() [1]\n\nGSO_BY_FRAGS is a forbidden value, but unfortunately the following\ncomputation in skb_segment() can reach it quite easily :\n\n\tmss = mss * partial_segs;\n\n65535 = 3 * 5 * 17 * 257, so many initial values of mss can lead to\na bad final result.\n\nMake sure to limit segmentation so that the new mss value is smaller\nthan GSO_BY_FRAGS.\n\n[1]\n\ngeneral protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN\nKASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]\nCPU: 1 PID: 5079 Comm: syz-executor993 Not tainted 6.7.0-rc4-syzkaller-00141-g1ae4cd3cbdd0 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023\nRIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551\nCode: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 \u003c0f\u003e b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00\nRSP: 0018:ffffc900043473d0 EFLAGS: 00010202\nRAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597\nRDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070\nRBP: ffffc90004347578 R08: 0000000000000005 R09: 000000000000ffff\nR10: 000000000000ffff R11: 0000000000000002 R12: ffff888063202ac0\nR13: 0000000000010000 R14: 000000000000ffff R15: 0000000000000046\nFS: 0000555556e7e380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000020010000 CR3: 0000000027ee2000 CR4: 00000000003506f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n\u003cTASK\u003e\nudp6_ufo_fragment+0xa0e/0xd00 net/ipv6/udp_offload.c:109\nipv6_gso_segment+0x534/0x17e0 net/ipv6/ip6_offload.c:120\nskb_mac_gso_segment+0x290/0x610 net/core/gso.c:53\n__skb_gso_segment+0x339/0x710 net/core/gso.c:124\nskb_gso_segment include/net/gso.h:83 [inline]\nvalidate_xmit_skb+0x36c/0xeb0 net/core/dev.c:3626\n__dev_queue_xmit+0x6f3/0x3d60 net/core/dev.c:4338\ndev_queue_xmit include/linux/netdevice.h:3134 [inline]\npacket_xmit+0x257/0x380 net/packet/af_packet.c:276\npacket_snd net/packet/af_packet.c:3087 [inline]\npacket_sendmsg+0x24c6/0x5220 net/packet/af_packet.c:3119\nsock_sendmsg_nosec net/socket.c:730 [inline]\n__sock_sendmsg+0xd5/0x180 net/socket.c:745\n__sys_sendto+0x255/0x340 net/socket.c:2190\n__do_sys_sendto net/socket.c:2202 [inline]\n__se_sys_sendto net/socket.c:2198 [inline]\n__x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198\ndo_syscall_x64 arch/x86/entry/common.c:52 [inline]\ndo_syscall_64+0x40/0x110 arch/x86/entry/common.c:83\nentry_SYSCALL_64_after_hwframe+0x63/0x6b\nRIP: 0033:0x7f8692032aa9\nCode: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007fff8d685418 EFLAGS: 00000246 ORIG_RAX: 000000000000002c\nRAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8692032aa9\nRDX: 0000000000010048 RSI: 00000000200000c0 RDI: 0000000000000003\nRBP: 00000000000f4240 R08: 0000000020000540 R09: 0000000000000014\nR10: 0000000000000000 R11: 0000000000000246 R12: 00007fff8d685480\nR13: 0000000000000001 R14: 00007fff8d685480 R15: 0000000000000003\n\u003c/TASK\u003e\nModules linked in:\n---[ end trace 0000000000000000 ]---\nRIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551\nCode: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 \u003c0f\u003e b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00\nRSP: 0018:ffffc900043473d0 EFLAGS: 00010202\nRAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597\nRDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070\nRBP: ffffc90004347578 R0\n---truncated---",
  "id": "GHSA-6vr7-3j3q-8546",
  "modified": "2024-09-04T12:30:36Z",
  "published": "2024-02-20T21:30:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-52435"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0d3ffbbf8631d6db0552f46250015648991c856f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/23d05d563b7e7b0314e65c8e882bc27eac2da8e7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6c53e8547687d9c767c139cd4b50af566f58c29a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8f8f185643747fbb448de6aab0efa51c679909a3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/95b3904a261a9f810205da560e802cc326f50d77"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/989b0ff35fe5fc9652ee5bafbe8483db6f27b137"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cd1022eaf87be8e6151435bd4df4c242c347e083"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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