FKIE_CVE-2025-37807
Vulnerability from fkie_nvd - Published: 2025-05-08 07:15 - Updated: 2026-10-21 13:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix kmemleak warning for percpu hashmap
Vlad Poenaru reported the following kmemleak issue:
unreferenced object 0x606fd7c44ac8 (size 32):
backtrace (crc 0):
pcpu_alloc_noprof+0x730/0xeb0
bpf_map_alloc_percpu+0x69/0xc0
prealloc_init+0x9d/0x1b0
htab_map_alloc+0x363/0x510
map_create+0x215/0x3a0
__sys_bpf+0x16b/0x3e0
__x64_sys_bpf+0x18/0x20
do_syscall_64+0x7b/0x150
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Further investigation shows the reason is due to not 8-byte aligned
store of percpu pointer in htab_elem_set_ptr():
*(void __percpu **)(l->key + key_size) = pptr;
Note that the whole htab_elem alignment is 8 (for x86_64). If the key_size
is 4, that means pptr is stored in a location which is 4 byte aligned but
not 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based
on 8 byte stride, so it won't detect above pptr, hence reporting the memory
leak.
In htab_map_alloc(), we already have
htab->elem_size = sizeof(struct htab_elem) +
round_up(htab->map.key_size, 8);
if (percpu)
htab->elem_size += sizeof(void *);
else
htab->elem_size += round_up(htab->map.value_size, 8);
So storing pptr with 8-byte alignment won't cause any problem and can fix
kmemleak too.
The issue can be reproduced with bpf selftest as well:
1. Enable CONFIG_DEBUG_KMEMLEAK config
2. Add a getchar() before skel destroy in test_hash_map() in prog_tests/for_each.c.
The purpose is to keep map available so kmemleak can be detected.
3. run './test_progs -t for_each/hash_map &' and a kmemleak should be reported.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/bpf/hashtab.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "25014e3dfa6d2fb95c920b9e6b2f0b303baa4533",
"status": "affected",
"version": "824bd0ce6c7c43a9e1e210abf124958e54d88342",
"versionType": "git"
},
{
"lessThan": "7758e308aeda1038aba1944f7302d34161b3effe",
"status": "affected",
"version": "824bd0ce6c7c43a9e1e210abf124958e54d88342",
"versionType": "git"
},
{
"lessThan": "1f1c29aa1934177349c17e3c32e68ec38a7a56df",
"status": "affected",
"version": "824bd0ce6c7c43a9e1e210abf124958e54d88342",
"versionType": "git"
},
{
"lessThan": "11ba7ce076e5903e7bdc1fd1498979c331b3c286",
"status": "affected",
"version": "824bd0ce6c7c43a9e1e210abf124958e54d88342",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/bpf/hashtab.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.6"
},
{
"lessThan": "4.6",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.26",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.14.*",
"status": "unaffected",
"version": "6.14.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.15",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "505F343C-3DE3-4984-A2E0-52BAFF9CC7CE",
"versionEndExcluding": "6.12.26",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "6B25CA7E-4CD0-46DB-B4EF-13A3516071FB",
"versionEndExcluding": "6.14.5",
"versionStartIncluding": "6.13",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix kmemleak warning for percpu hashmap\n\nVlad Poenaru reported the following kmemleak issue:\n\n unreferenced object 0x606fd7c44ac8 (size 32):\n backtrace (crc 0):\n pcpu_alloc_noprof+0x730/0xeb0\n bpf_map_alloc_percpu+0x69/0xc0\n prealloc_init+0x9d/0x1b0\n htab_map_alloc+0x363/0x510\n map_create+0x215/0x3a0\n __sys_bpf+0x16b/0x3e0\n __x64_sys_bpf+0x18/0x20\n do_syscall_64+0x7b/0x150\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\nFurther investigation shows the reason is due to not 8-byte aligned\nstore of percpu pointer in htab_elem_set_ptr():\n *(void __percpu **)(l-\u003ekey + key_size) = pptr;\n\nNote that the whole htab_elem alignment is 8 (for x86_64). If the key_size\nis 4, that means pptr is stored in a location which is 4 byte aligned but\nnot 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based\non 8 byte stride, so it won\u0027t detect above pptr, hence reporting the memory\nleak.\n\nIn htab_map_alloc(), we already have\n\n htab-\u003eelem_size = sizeof(struct htab_elem) +\n round_up(htab-\u003emap.key_size, 8);\n if (percpu)\n htab-\u003eelem_size += sizeof(void *);\n else\n htab-\u003eelem_size += round_up(htab-\u003emap.value_size, 8);\n\nSo storing pptr with 8-byte alignment won\u0027t cause any problem and can fix\nkmemleak too.\n\nThe issue can be reproduced with bpf selftest as well:\n 1. Enable CONFIG_DEBUG_KMEMLEAK config\n 2. Add a getchar() before skel destroy in test_hash_map() in prog_tests/for_each.c.\n The purpose is to keep map available so kmemleak can be detected.\n 3. run \u0027./test_progs -t for_each/hash_map \u0026\u0027 and a kmemleak should be reported."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: Se corrige la advertencia de kmemleak para el mapa hash de percpu Vlad Poenaru inform\u00f3 el siguiente problema de kmemleak: objeto sin referencia 0x606fd7c44ac8 (tama\u00f1o 32): backtrace (crc 0): pcpu_alloc_noprof+0x730/0xeb0 bpf_map_alloc_percpu+0x69/0xc0 prealloc_init+0x9d/0x1b0 htab_map_alloc+0x363/0x510 map_create+0x215/0x3a0 __sys_bpf+0x16b/0x3e0 __x64_sys_bpf+0x18/0x20 do_syscall_64+0x7b/0x150 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Una investigaci\u00f3n m\u00e1s profunda muestra que la raz\u00f3n se debe a un almacenamiento no alineado de 8 bytes del puntero por CPU en htab_elem_set_ptr(): *(void __percpu **)(l-\u0026gt;key + key_size) = pptr; Tenga en cuenta que la alineaci\u00f3n completa de htab_elem es 8 (para x86_64). Si key_size es 4, significa que pptr se almacena en una ubicaci\u00f3n que est\u00e1 alineada con 4 bytes pero no con 8 bytes. En mm/kmemleak.c, scan_block() escanea la memoria bas\u00e1ndose en un paso de 8 bytes, por lo que no detectar\u00e1 por encima de pptr, por lo que informa la p\u00e9rdida de memoria. En htab_map_alloc(), ya tenemos htab-\u0026gt;elem_size = sizeof(struct htab_elem) + round_up(htab-\u0026gt;map.key_size, 8); if (percpu) htab-\u0026gt;elem_size += sizeof(void *); else htab-\u0026gt;elem_size += round_up(htab-\u0026gt;map.value_size, 8); Por lo tanto, almacenar pptr con alineaci\u00f3n de 8 bytes no causar\u00e1 ning\u00fan problema y tambi\u00e9n puede solucionar la fuga de kmem. El problema tambi\u00e9n se puede reproducir con la autoprueba de BPF: 1. Habilite la configuraci\u00f3n CONFIG_DEBUG_KMEMLEAK. 2. A\u00f1ada un getchar() antes de skel destroy en test_hash_map() en prog_tests/for_each.c. El objetivo es mantener el mapa disponible para que se pueda detectar la fuga de kmem. 3. Ejecute \u0027./test_progs -t for_each/hash_map \u0026amp;\u0027 y se deber\u00eda informar de una fuga de kmem."
}
],
"id": "CVE-2025-37807",
"lastModified": "2026-10-21T13:18:06.520",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2025-05-08T07:15:51.873",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/11ba7ce076e5903e7bdc1fd1498979c331b3c286"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/1f1c29aa1934177349c17e3c32e68ec38a7a56df"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/25014e3dfa6d2fb95c920b9e6b2f0b303baa4533"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/7758e308aeda1038aba1944f7302d34161b3effe"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-401"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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