ghsa-jgf3-fmmf-vj4h
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
bpf: sync_linked_regs() must preserve subreg_def
Range propagation must not affect subreg_def marks, otherwise the following example is rewritten by verifier incorrectly when BPF_F_TEST_RND_HI32 flag is set:
0: call bpf_ktime_get_ns call bpf_ktime_get_ns 1: r0 &= 0x7fffffff after verifier r0 &= 0x7fffffff 2: w1 = w0 rewrites w1 = w0 3: if w0 < 10 goto +0 --------------> r11 = 0x2f5674a6 (r) 4: r1 >>= 32 r11 <<= 32 (r) 5: r0 = r1 r1 |= r11 (r) 6: exit; if w0 < 0xa goto pc+0 r1 >>= 32 r0 = r1 exit
(or zero extension of w1 at (2) is missing for architectures that require zero extension for upper register half).
The following happens w/o this patch: - r0 is marked as not a subreg at (0); - w1 is marked as subreg at (2); - w1 subreg_def is overridden at (3) by copy_register_state(); - w1 is read at (5) but mark_insn_zext() does not mark (2) for zero extension, because w1 subreg_def is not set; - because of BPF_F_TEST_RND_HI32 flag verifier inserts random value for hi32 bits of (2) (marked (r)); - this random value is read at (5).
{
"affected": [],
"aliases": [
"CVE-2024-53125"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-12-04T14:15:20Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: sync_linked_regs() must preserve subreg_def\n\nRange propagation must not affect subreg_def marks, otherwise the\nfollowing example is rewritten by verifier incorrectly when\nBPF_F_TEST_RND_HI32 flag is set:\n\n 0: call bpf_ktime_get_ns call bpf_ktime_get_ns\n 1: r0 \u0026= 0x7fffffff after verifier r0 \u0026= 0x7fffffff\n 2: w1 = w0 rewrites w1 = w0\n 3: if w0 \u003c 10 goto +0 --------------\u003e r11 = 0x2f5674a6 (r)\n 4: r1 \u003e\u003e= 32 r11 \u003c\u003c= 32 (r)\n 5: r0 = r1 r1 |= r11 (r)\n 6: exit; if w0 \u003c 0xa goto pc+0\n r1 \u003e\u003e= 32\n r0 = r1\n exit\n\n(or zero extension of w1 at (2) is missing for architectures that\n require zero extension for upper register half).\n\nThe following happens w/o this patch:\n- r0 is marked as not a subreg at (0);\n- w1 is marked as subreg at (2);\n- w1 subreg_def is overridden at (3) by copy_register_state();\n- w1 is read at (5) but mark_insn_zext() does not mark (2)\n for zero extension, because w1 subreg_def is not set;\n- because of BPF_F_TEST_RND_HI32 flag verifier inserts random\n value for hi32 bits of (2) (marked (r));\n- this random value is read at (5).",
"id": "GHSA-jgf3-fmmf-vj4h",
"modified": "2024-12-04T15:31:52Z",
"published": "2024-12-04T15:31:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-53125"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e2ef0f317a52e678fe8fa84b94d6a15b466d6ff0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e9bd9c498cb0f5843996dbe5cbce7a1836a83c70"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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