CVE-2021-47221

See a problem?
Please try reporting it to the source first.
Source
https://cve.org/CVERecord?id=CVE-2021-47221
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47221.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2021-47221
Downstream
Published
2024-05-21T15:15:11.380Z
Modified
2026-03-15T22:43:08.494645Z
Severity
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
[none]
Details

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

mm/slub: actually fix freelist pointer vs redzoning

It turns out that SLUB redzoning ("slubdebug=Z") checks from s->objectsize rather than from s->inuse (which is normally bumped to make room for the freelist pointer), so a cache created with an object size less than 24 would have the freelist pointer written beyond s->objectsize, causing the redzone to be corrupted by the freelist pointer. This was very visible with "slubdebug=ZF":

BUG test (Tainted: G B ): Right Redzone overwritten

INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200 INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620

Redzone (ptrval): bb bb bb bb bb bb bb bb ........ Object (ptrval): 00 00 00 00 00 f6 f4 a5 ........ Redzone (ptrval): 40 1d e8 1a aa @.... Padding (ptrval): 00 00 00 00 00 00 00 00 ........

Adjust the offset to stay within s->object_size.

(Note that no caches of in this size range are known to exist in the kernel currently.)

References

Affected packages

Git /

Affected ranges

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47221.json"
unresolved_ranges 
[
    {
        "events": [
            {
                "introduced": "5.7"
            },
            {
                "fixed": "5.10.46"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "5.11"
            },
            {
                "fixed": "5.12.13"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "5.13-rc1"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "5.13-rc2"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "5.13-rc3"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "5.13-rc4"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "5.13-rc5"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "5.13-rc6"
            }
        ]
    }
]