ghsa-5469-6p3j-2hpr
Vulnerability from github
Published
2024-08-26 12:31
Modified
2024-09-05 18:30
Details

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

bpf: add missing check_func_arg_reg_off() to prevent out-of-bounds memory accesses

Currently, it's possible to pass in a modified CONST_PTR_TO_DYNPTR to a global function as an argument. The adverse effects of this is that BPF helpers can continue to make use of this modified CONST_PTR_TO_DYNPTR from within the context of the global function, which can unintentionally result in out-of-bounds memory accesses and therefore compromise overall system stability i.e.

[ 244.157771] BUG: KASAN: slab-out-of-bounds in bpf_dynptr_data+0x137/0x140 [ 244.161345] Read of size 8 at addr ffff88810914be68 by task test_progs/302 [ 244.167151] CPU: 0 PID: 302 Comm: test_progs Tainted: G O E 6.10.0-rc3-00131-g66b586715063 #533 [ 244.174318] Call Trace: [ 244.175787] [ 244.177356] dump_stack_lvl+0x66/0xa0 [ 244.179531] print_report+0xce/0x670 [ 244.182314] ? __virt_addr_valid+0x200/0x3e0 [ 244.184908] kasan_report+0xd7/0x110 [ 244.187408] ? bpf_dynptr_data+0x137/0x140 [ 244.189714] ? bpf_dynptr_data+0x137/0x140 [ 244.192020] bpf_dynptr_data+0x137/0x140 [ 244.194264] bpf_prog_b02a02fdd2bdc5fa_global_call_bpf_dynptr_data+0x22/0x26 [ 244.198044] bpf_prog_b0fe7b9d7dc3abde_callback_adjust_bpf_dynptr_reg_off+0x1f/0x23 [ 244.202136] bpf_user_ringbuf_drain+0x2c7/0x570 [ 244.204744] ? 0xffffffffc0009e58 [ 244.206593] ? __pfx_bpf_user_ringbuf_drain+0x10/0x10 [ 244.209795] bpf_prog_33ab33f6a804ba2d_user_ringbuf_callback_const_ptr_to_dynptr_reg_off+0x47/0x4b [ 244.215922] bpf_trampoline_6442502480+0x43/0xe3 [ 244.218691] __x64_sys_prlimit64+0x9/0xf0 [ 244.220912] do_syscall_64+0xc1/0x1d0 [ 244.223043] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 244.226458] RIP: 0033:0x7ffa3eb8f059 [ 244.228582] Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 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 8b 0d 8f 1d 0d 00 f7 d8 64 89 01 48 [ 244.241307] RSP: 002b:00007ffa3e9c6eb8 EFLAGS: 00000206 ORIG_RAX: 000000000000012e [ 244.246474] RAX: ffffffffffffffda RBX: 00007ffa3e9c7cdc RCX: 00007ffa3eb8f059 [ 244.250478] RDX: 00007ffa3eb162b4 RSI: 0000000000000000 RDI: 00007ffa3e9c7fb0 [ 244.255396] RBP: 00007ffa3e9c6ed0 R08: 00007ffa3e9c76c0 R09: 0000000000000000 [ 244.260195] R10: 0000000000000000 R11: 0000000000000206 R12: ffffffffffffff80 [ 244.264201] R13: 000000000000001c R14: 00007ffc5d6b4260 R15: 00007ffa3e1c7000 [ 244.268303]

Add a check_func_arg_reg_off() to the path in which the BPF verifier verifies the arguments of global function arguments, specifically those which take an argument of type ARG_PTR_TO_DYNPTR | MEM_RDONLY. Also, process_dynptr_func() doesn't appear to perform any explicit and strict type matching on the supplied register type, so let's also enforce that a register either type PTR_TO_STACK or CONST_PTR_TO_DYNPTR is by the caller.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2024-43910"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-08-26T11:15:05Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: add missing check_func_arg_reg_off() to prevent out-of-bounds memory accesses\n\nCurrently, it\u0027s possible to pass in a modified CONST_PTR_TO_DYNPTR to\na global function as an argument. The adverse effects of this is that\nBPF helpers can continue to make use of this modified\nCONST_PTR_TO_DYNPTR from within the context of the global function,\nwhich can unintentionally result in out-of-bounds memory accesses and\ntherefore compromise overall system stability i.e.\n\n[  244.157771] BUG: KASAN: slab-out-of-bounds in bpf_dynptr_data+0x137/0x140\n[  244.161345] Read of size 8 at addr ffff88810914be68 by task test_progs/302\n[  244.167151] CPU: 0 PID: 302 Comm: test_progs Tainted: G O E 6.10.0-rc3-00131-g66b586715063 #533\n[  244.174318] Call Trace:\n[  244.175787]  \u003cTASK\u003e\n[  244.177356]  dump_stack_lvl+0x66/0xa0\n[  244.179531]  print_report+0xce/0x670\n[  244.182314]  ? __virt_addr_valid+0x200/0x3e0\n[  244.184908]  kasan_report+0xd7/0x110\n[  244.187408]  ? bpf_dynptr_data+0x137/0x140\n[  244.189714]  ? bpf_dynptr_data+0x137/0x140\n[  244.192020]  bpf_dynptr_data+0x137/0x140\n[  244.194264]  bpf_prog_b02a02fdd2bdc5fa_global_call_bpf_dynptr_data+0x22/0x26\n[  244.198044]  bpf_prog_b0fe7b9d7dc3abde_callback_adjust_bpf_dynptr_reg_off+0x1f/0x23\n[  244.202136]  bpf_user_ringbuf_drain+0x2c7/0x570\n[  244.204744]  ? 0xffffffffc0009e58\n[  244.206593]  ? __pfx_bpf_user_ringbuf_drain+0x10/0x10\n[  244.209795]  bpf_prog_33ab33f6a804ba2d_user_ringbuf_callback_const_ptr_to_dynptr_reg_off+0x47/0x4b\n[  244.215922]  bpf_trampoline_6442502480+0x43/0xe3\n[  244.218691]  __x64_sys_prlimit64+0x9/0xf0\n[  244.220912]  do_syscall_64+0xc1/0x1d0\n[  244.223043]  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[  244.226458] RIP: 0033:0x7ffa3eb8f059\n[  244.228582] Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 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 8b 0d 8f 1d 0d 00 f7 d8 64 89 01 48\n[  244.241307] RSP: 002b:00007ffa3e9c6eb8 EFLAGS: 00000206 ORIG_RAX: 000000000000012e\n[  244.246474] RAX: ffffffffffffffda RBX: 00007ffa3e9c7cdc RCX: 00007ffa3eb8f059\n[  244.250478] RDX: 00007ffa3eb162b4 RSI: 0000000000000000 RDI: 00007ffa3e9c7fb0\n[  244.255396] RBP: 00007ffa3e9c6ed0 R08: 00007ffa3e9c76c0 R09: 0000000000000000\n[  244.260195] R10: 0000000000000000 R11: 0000000000000206 R12: ffffffffffffff80\n[  244.264201] R13: 000000000000001c R14: 00007ffc5d6b4260 R15: 00007ffa3e1c7000\n[  244.268303]  \u003c/TASK\u003e\n\nAdd a check_func_arg_reg_off() to the path in which the BPF verifier\nverifies the arguments of global function arguments, specifically\nthose which take an argument of type ARG_PTR_TO_DYNPTR |\nMEM_RDONLY. Also, process_dynptr_func() doesn\u0027t appear to perform any\nexplicit and strict type matching on the supplied register type, so\nlet\u0027s also enforce that a register either type PTR_TO_STACK or\nCONST_PTR_TO_DYNPTR is by the caller.",
  "id": "GHSA-5469-6p3j-2hpr",
  "modified": "2024-09-05T18:30:51Z",
  "published": "2024-08-26T12:31:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-43910"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/13663a7c644bf1dedaf461d07252db5d76c8759a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ec2b9a5e11e51fea1bb04c1e7e471952e887e874"
    }
  ],
  "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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