ghsa-g58j-c94r-957c
Vulnerability from github
Published
2025-12-24 15:30
Modified
2025-12-24 15:30
Details

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

net: nsh: Use correct mac_offset to unwind gso skb in nsh_gso_segment()

As the call trace shows, skb_panic was caused by wrong skb->mac_header in nsh_gso_segment():

invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 3 PID: 2737 Comm: syz Not tainted 6.3.0-next-20230505 #1 RIP: 0010:skb_panic+0xda/0xe0 call Trace: skb_push+0x91/0xa0 nsh_gso_segment+0x4f3/0x570 skb_mac_gso_segment+0x19e/0x270 __skb_gso_segment+0x1e8/0x3c0 validate_xmit_skb+0x452/0x890 validate_xmit_skb_list+0x99/0xd0 sch_direct_xmit+0x294/0x7c0 __dev_queue_xmit+0x16f0/0x1d70 packet_xmit+0x185/0x210 packet_snd+0xc15/0x1170 packet_sendmsg+0x7b/0xa0 sock_sendmsg+0x14f/0x160

The root cause is: nsh_gso_segment() use skb->network_header - nhoff to reset mac_header in skb_gso_error_unwind() if inner-layer protocol gso fails. However, skb->network_header may be reset by inner-layer protocol gso function e.g. mpls_gso_segment. skb->mac_header reset by the inaccurate network_header will be larger than skb headroom.

nsh_gso_segment nhoff = skb->network_header - skb->mac_header; __skb_pull(skb,nsh_len) skb_mac_gso_segment mpls_gso_segment skb_reset_network_header(skb);//skb->network_header+=nsh_len return -EINVAL; skb_gso_error_unwind skb_push(skb, nsh_len); skb->mac_header = skb->network_header - nhoff; // skb->mac_header > skb->headroom, cause skb_push panic

Use correct mac_offset to restore mac_header and get rid of nhoff.

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{
  "affected": [],
  "aliases": [
    "CVE-2023-54114"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-24T13:16:13Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: nsh: Use correct mac_offset to unwind gso skb in nsh_gso_segment()\n\nAs the call trace shows, skb_panic was caused by wrong skb-\u003emac_header\nin nsh_gso_segment():\n\ninvalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI\nCPU: 3 PID: 2737 Comm: syz Not tainted 6.3.0-next-20230505 #1\nRIP: 0010:skb_panic+0xda/0xe0\ncall Trace:\n skb_push+0x91/0xa0\n nsh_gso_segment+0x4f3/0x570\n skb_mac_gso_segment+0x19e/0x270\n __skb_gso_segment+0x1e8/0x3c0\n validate_xmit_skb+0x452/0x890\n validate_xmit_skb_list+0x99/0xd0\n sch_direct_xmit+0x294/0x7c0\n __dev_queue_xmit+0x16f0/0x1d70\n packet_xmit+0x185/0x210\n packet_snd+0xc15/0x1170\n packet_sendmsg+0x7b/0xa0\n sock_sendmsg+0x14f/0x160\n\nThe root cause is:\nnsh_gso_segment() use skb-\u003enetwork_header - nhoff to reset mac_header\nin skb_gso_error_unwind() if inner-layer protocol gso fails.\nHowever, skb-\u003enetwork_header may be reset by inner-layer protocol\ngso function e.g. mpls_gso_segment. skb-\u003emac_header reset by the\ninaccurate network_header will be larger than skb headroom.\n\nnsh_gso_segment\n    nhoff = skb-\u003enetwork_header - skb-\u003emac_header;\n    __skb_pull(skb,nsh_len)\n    skb_mac_gso_segment\n        mpls_gso_segment\n            skb_reset_network_header(skb);//skb-\u003enetwork_header+=nsh_len\n            return -EINVAL;\n    skb_gso_error_unwind\n        skb_push(skb, nsh_len);\n        skb-\u003emac_header = skb-\u003enetwork_header - nhoff;\n        // skb-\u003emac_header \u003e skb-\u003eheadroom, cause skb_push panic\n\nUse correct mac_offset to restore mac_header and get rid of nhoff.",
  "id": "GHSA-g58j-c94r-957c",
  "modified": "2025-12-24T15:30:38Z",
  "published": "2025-12-24T15:30:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-54114"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/02b20e0bc0c2628539e9e518dc342787c3332de2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2f88c8d38ecf5ed0273f99a067246899ba499eb2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/435855b0831b351cb72cb38369ee33122ce9574c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6fbedf987b6b8ed54a50e2205d998eb2c8be72f9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c83b49383b595be50647f0c764a48c78b5f3c4f8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cb38e62922aa3991793344b5a5870e7291c74a44"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cdd8160dcda1fed2028a5f96575a84afc23aff7d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d2309e0cb27b6871b273fbc1725e93be62570d86"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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