ghsa-hw24-w8rj-6q65
Vulnerability from github
Published
2025-10-28 12:30
Modified
2025-10-28 12:30
Details

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

riscv, bpf: Sign extend struct ops return values properly

The ns_bpf_qdisc selftest triggers a kernel panic:

Unable to handle kernel paging request at virtual address ffffffffa38dbf58
Current test_progs pgtable: 4K pagesize, 57-bit VAs, pgdp=0x00000001109cc000
[ffffffffa38dbf58] pgd=000000011fffd801, p4d=000000011fffd401, pud=000000011fffd001, pmd=0000000000000000
Oops [#1]
Modules linked in: bpf_testmod(OE) xt_conntrack nls_iso8859_1 [...] [last unloaded: bpf_testmod(OE)]
CPU: 1 UID: 0 PID: 23584 Comm: test_progs Tainted: G        W  OE       6.17.0-rc1-g2465bb83e0b4 #1 NONE
Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2024.01+dfsg-1ubuntu5.1 01/01/2024
epc : __qdisc_run+0x82/0x6f0
 ra : __qdisc_run+0x6e/0x6f0
epc : ffffffff80bd5c7a ra : ffffffff80bd5c66 sp : ff2000000eecb550
 gp : ffffffff82472098 tp : ff60000096895940 t0 : ffffffff8001f180
 t1 : ffffffff801e1664 t2 : 0000000000000000 s0 : ff2000000eecb5d0
 s1 : ff60000093a6a600 a0 : ffffffffa38dbee8 a1 : 0000000000000001
 a2 : ff2000000eecb510 a3 : 0000000000000001 a4 : 0000000000000000
 a5 : 0000000000000010 a6 : 0000000000000000 a7 : 0000000000735049
 s2 : ffffffffa38dbee8 s3 : 0000000000000040 s4 : ff6000008bcda000
 s5 : 0000000000000008 s6 : ff60000093a6a680 s7 : ff60000093a6a6f0
 s8 : ff60000093a6a6ac s9 : ff60000093140000 s10: 0000000000000000
 s11: ff2000000eecb9d0 t3 : 0000000000000000 t4 : 0000000000ff0000
 t5 : 0000000000000000 t6 : ff60000093a6a8b6
status: 0000000200000120 badaddr: ffffffffa38dbf58 cause: 000000000000000d
[<ffffffff80bd5c7a>] __qdisc_run+0x82/0x6f0
[<ffffffff80b6fe58>] __dev_queue_xmit+0x4c0/0x1128
[<ffffffff80b80ae0>] neigh_resolve_output+0xd0/0x170
[<ffffffff80d2daf6>] ip6_finish_output2+0x226/0x6c8
[<ffffffff80d31254>] ip6_finish_output+0x10c/0x2a0
[<ffffffff80d31446>] ip6_output+0x5e/0x178
[<ffffffff80d2e232>] ip6_xmit+0x29a/0x608
[<ffffffff80d6f4c6>] inet6_csk_xmit+0xe6/0x140
[<ffffffff80c985e4>] __tcp_transmit_skb+0x45c/0xaa8
[<ffffffff80c995fe>] tcp_connect+0x9ce/0xd10
[<ffffffff80d66524>] tcp_v6_connect+0x4ac/0x5e8
[<ffffffff80cc19b8>] __inet_stream_connect+0xd8/0x318
[<ffffffff80cc1c36>] inet_stream_connect+0x3e/0x68
[<ffffffff80b42b20>] __sys_connect_file+0x50/0x88
[<ffffffff80b42bee>] __sys_connect+0x96/0xc8
[<ffffffff80b42c40>] __riscv_sys_connect+0x20/0x30
[<ffffffff80e5bcae>] do_trap_ecall_u+0x256/0x378
[<ffffffff80e69af2>] handle_exception+0x14a/0x156
Code: 892a 0363 1205 489c 8bc1 c7e5 2d03 084a 2703 080a (2783) 0709
---[ end trace 0000000000000000 ]---

The bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer is treated as a 32bit value and sign extend to 64bit in epilogue. This behavior is right for most bpf prog types but wrong for struct ops which requires RISC-V ABI.

So let's sign extend struct ops return values according to the function model and RISC-V ABI(0).

Show details on source website

To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2025-40079"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-10-28T12:15:42Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nriscv, bpf: Sign extend struct ops return values properly\n\nThe ns_bpf_qdisc selftest triggers a kernel panic:\n\n    Unable to handle kernel paging request at virtual address ffffffffa38dbf58\n    Current test_progs pgtable: 4K pagesize, 57-bit VAs, pgdp=0x00000001109cc000\n    [ffffffffa38dbf58] pgd=000000011fffd801, p4d=000000011fffd401, pud=000000011fffd001, pmd=0000000000000000\n    Oops [#1]\n    Modules linked in: bpf_testmod(OE) xt_conntrack nls_iso8859_1 [...] [last unloaded: bpf_testmod(OE)]\n    CPU: 1 UID: 0 PID: 23584 Comm: test_progs Tainted: G        W  OE       6.17.0-rc1-g2465bb83e0b4 #1 NONE\n    Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\n    Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2024.01+dfsg-1ubuntu5.1 01/01/2024\n    epc : __qdisc_run+0x82/0x6f0\n     ra : __qdisc_run+0x6e/0x6f0\n    epc : ffffffff80bd5c7a ra : ffffffff80bd5c66 sp : ff2000000eecb550\n     gp : ffffffff82472098 tp : ff60000096895940 t0 : ffffffff8001f180\n     t1 : ffffffff801e1664 t2 : 0000000000000000 s0 : ff2000000eecb5d0\n     s1 : ff60000093a6a600 a0 : ffffffffa38dbee8 a1 : 0000000000000001\n     a2 : ff2000000eecb510 a3 : 0000000000000001 a4 : 0000000000000000\n     a5 : 0000000000000010 a6 : 0000000000000000 a7 : 0000000000735049\n     s2 : ffffffffa38dbee8 s3 : 0000000000000040 s4 : ff6000008bcda000\n     s5 : 0000000000000008 s6 : ff60000093a6a680 s7 : ff60000093a6a6f0\n     s8 : ff60000093a6a6ac s9 : ff60000093140000 s10: 0000000000000000\n     s11: ff2000000eecb9d0 t3 : 0000000000000000 t4 : 0000000000ff0000\n     t5 : 0000000000000000 t6 : ff60000093a6a8b6\n    status: 0000000200000120 badaddr: ffffffffa38dbf58 cause: 000000000000000d\n    [\u003cffffffff80bd5c7a\u003e] __qdisc_run+0x82/0x6f0\n    [\u003cffffffff80b6fe58\u003e] __dev_queue_xmit+0x4c0/0x1128\n    [\u003cffffffff80b80ae0\u003e] neigh_resolve_output+0xd0/0x170\n    [\u003cffffffff80d2daf6\u003e] ip6_finish_output2+0x226/0x6c8\n    [\u003cffffffff80d31254\u003e] ip6_finish_output+0x10c/0x2a0\n    [\u003cffffffff80d31446\u003e] ip6_output+0x5e/0x178\n    [\u003cffffffff80d2e232\u003e] ip6_xmit+0x29a/0x608\n    [\u003cffffffff80d6f4c6\u003e] inet6_csk_xmit+0xe6/0x140\n    [\u003cffffffff80c985e4\u003e] __tcp_transmit_skb+0x45c/0xaa8\n    [\u003cffffffff80c995fe\u003e] tcp_connect+0x9ce/0xd10\n    [\u003cffffffff80d66524\u003e] tcp_v6_connect+0x4ac/0x5e8\n    [\u003cffffffff80cc19b8\u003e] __inet_stream_connect+0xd8/0x318\n    [\u003cffffffff80cc1c36\u003e] inet_stream_connect+0x3e/0x68\n    [\u003cffffffff80b42b20\u003e] __sys_connect_file+0x50/0x88\n    [\u003cffffffff80b42bee\u003e] __sys_connect+0x96/0xc8\n    [\u003cffffffff80b42c40\u003e] __riscv_sys_connect+0x20/0x30\n    [\u003cffffffff80e5bcae\u003e] do_trap_ecall_u+0x256/0x378\n    [\u003cffffffff80e69af2\u003e] handle_exception+0x14a/0x156\n    Code: 892a 0363 1205 489c 8bc1 c7e5 2d03 084a 2703 080a (2783) 0709\n    ---[ end trace 0000000000000000 ]---\n\nThe bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer\nis treated as a 32bit value and sign extend to 64bit in epilogue. This\nbehavior is right for most bpf prog types but wrong for struct ops which\nrequires RISC-V ABI.\n\nSo let\u0027s sign extend struct ops return values according to the function\nmodel and RISC-V ABI([0]).\n\n  [0]: https://riscv.org/wp-content/uploads/2024/12/riscv-calling.pdf",
  "id": "GHSA-hw24-w8rj-6q65",
  "modified": "2025-10-28T12:30:17Z",
  "published": "2025-10-28T12:30:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40079"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/92751937f12a7d34ad492577a251c94a55e97e72"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fd2e08128944a7679e753f920e9eda72057e427c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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