ghsa-wwjm-jqc7-c985
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix stackmap overflow check on 32-bit arches
The stackmap code relies on roundup_pow_of_two() to compute the number of hash buckets, and contains an overflow check by checking if the resulting value is 0. However, on 32-bit arches, the roundup code itself can overflow by doing a 32-bit left-shift of an unsigned long value, which is undefined behaviour, so it is not guaranteed to truncate neatly. This was triggered by syzbot on the DEVMAP_HASH type, which contains the same check, copied from the hashtab code.
The commit in the fixes tag actually attempted to fix this, but the fix did not account for the UB, so the fix only works on CPUs where an overflow does result in a neat truncation to zero, which is not guaranteed. Checking the value before rounding does not have this problem.
{
"affected": [],
"aliases": [
"CVE-2024-26883"
],
"database_specific": {
"cwe_ids": [
"CWE-119"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-17T11:15:10Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix stackmap overflow check on 32-bit arches\n\nThe stackmap code relies on roundup_pow_of_two() to compute the number\nof hash buckets, and contains an overflow check by checking if the\nresulting value is 0. However, on 32-bit arches, the roundup code itself\ncan overflow by doing a 32-bit left-shift of an unsigned long value,\nwhich is undefined behaviour, so it is not guaranteed to truncate\nneatly. This was triggered by syzbot on the DEVMAP_HASH type, which\ncontains the same check, copied from the hashtab code.\n\nThe commit in the fixes tag actually attempted to fix this, but the fix\ndid not account for the UB, so the fix only works on CPUs where an\noverflow does result in a neat truncation to zero, which is not\nguaranteed. Checking the value before rounding does not have this\nproblem.",
"id": "GHSA-wwjm-jqc7-c985",
"modified": "2024-06-27T12:30:45Z",
"published": "2024-04-17T12:32:05Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26883"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0971126c8164abe2004b8536b49690a0d6005b0a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/15641007df0f0d35fa28742b25c2a7db9dcd6895"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/21e5fa4688e1a4d3db6b72216231b24232f75c1d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/43f798b9036491fb014b55dd61c4c5c3193267d0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7070b274c7866a4c5036f8d54fcaf315c64ac33a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7a4b21250bf79eef26543d35bd390448646c536b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ca1f06e72dec41ae4f76e7b1a8a97265447b46ae"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d0e214acc59145ce25113f617311aa79dda39cb3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f06899582ccee09bd85d0696290e3eaca9aa042d"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}