ghsa-5mmf-rjpr-m4cj
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
fork: only invoke khugepaged, ksm hooks if no error
There is no reason to invoke these hooks early against an mm that is in an incomplete state.
The change in commit d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") makes this more pertinent as we may be in a state where entries in the maple tree are not yet consistent.
Their placement early in dup_mmap() only appears to have been meaningful for early error checking, and since functionally it'd require a very small allocation to fail (in practice 'too small to fail') that'd only occur in the most dire circumstances, meaning the fork would fail or be OOM'd in any case.
Since both khugepaged and KSM tracking are there to provide optimisations to memory performance rather than critical functionality, it doesn't really matter all that much if, under such dire memory pressure, we fail to register an mm with these.
As a result, we follow the example of commit d2081b2bf819 ("mm: khugepaged: make khugepaged_enter() void function") and make ksm_fork() a void function also.
We only expose the mm to these functions once we are done with them and only if no error occurred in the fork operation.
{
"affected": [],
"aliases": [
"CVE-2024-50263"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-11-11T14:15:15Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfork: only invoke khugepaged, ksm hooks if no error\n\nThere is no reason to invoke these hooks early against an mm that is in an\nincomplete state.\n\nThe change in commit d24062914837 (\"fork: use __mt_dup() to duplicate\nmaple tree in dup_mmap()\") makes this more pertinent as we may be in a\nstate where entries in the maple tree are not yet consistent.\n\nTheir placement early in dup_mmap() only appears to have been meaningful\nfor early error checking, and since functionally it\u0027d require a very small\nallocation to fail (in practice \u0027too small to fail\u0027) that\u0027d only occur in\nthe most dire circumstances, meaning the fork would fail or be OOM\u0027d in\nany case.\n\nSince both khugepaged and KSM tracking are there to provide optimisations\nto memory performance rather than critical functionality, it doesn\u0027t\nreally matter all that much if, under such dire memory pressure, we fail\nto register an mm with these.\n\nAs a result, we follow the example of commit d2081b2bf819 (\"mm:\nkhugepaged: make khugepaged_enter() void function\") and make ksm_fork() a\nvoid function also.\n\nWe only expose the mm to these functions once we are done with them and\nonly if no error occurred in the fork operation.",
"id": "GHSA-5mmf-rjpr-m4cj",
"modified": "2024-12-10T00:31:26Z",
"published": "2024-11-11T15:31:02Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-50263"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3b85aa0da8cd01173b9afd1f70080fbb9576c4b0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/985da552a98e27096444508ce5d853244019111f"
},
{
"type": "WEB",
"url": "https://project-zero.issues.chromium.org/issues/373391951"
}
],
"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"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.