ghsa-jpp4-rwwf-g5qm
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type
On 64-bit platforms, the pfn_to_kaddr() macro requires that the input value is 64 bits in order to ensure that valid address bits don't get lost when shifting that input by PAGE_SHIFT to calculate the physical address to provide a virtual address for.
One such example is in pvalidate_pages() (used by SEV-SNP guests), where the GFN in the struct used for page-state change requests is a 40-bit bit-field, so attempts to pass this GFN field directly into pfn_to_kaddr() ends up causing guest crashes when dealing with addresses above the 1TB range due to the above.
Fix this issue with SEV-SNP guests, as well as any similar cases that might cause issues in current/future code, by using an inline function, instead of a macro, so that the input is implicitly cast to the expected 64-bit input type prior to performing the shift operation.
While it might be argued that the issue is on the caller side, other archs/macros have taken similar approaches to deal with instances like this, such as ARM explicitly casting the input to phys_addr_t:
e48866647b48 ("ARM: 8396/1: use phys_addr_t in pfn_to_kaddr()")
A C inline function is even better though.
[ mingo: Refined the changelog some more & added __always_inline. ]
{
"affected": [],
"aliases": [
"CVE-2023-52659"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-17T13:15:57Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type\n\nOn 64-bit platforms, the pfn_to_kaddr() macro requires that the input\nvalue is 64 bits in order to ensure that valid address bits don\u0027t get\nlost when shifting that input by PAGE_SHIFT to calculate the physical\naddress to provide a virtual address for.\n\nOne such example is in pvalidate_pages() (used by SEV-SNP guests), where\nthe GFN in the struct used for page-state change requests is a 40-bit\nbit-field, so attempts to pass this GFN field directly into\npfn_to_kaddr() ends up causing guest crashes when dealing with addresses\nabove the 1TB range due to the above.\n\nFix this issue with SEV-SNP guests, as well as any similar cases that\nmight cause issues in current/future code, by using an inline function,\ninstead of a macro, so that the input is implicitly cast to the\nexpected 64-bit input type prior to performing the shift operation.\n\nWhile it might be argued that the issue is on the caller side, other\narchs/macros have taken similar approaches to deal with instances like\nthis, such as ARM explicitly casting the input to phys_addr_t:\n\n e48866647b48 (\"ARM: 8396/1: use phys_addr_t in pfn_to_kaddr()\")\n\nA C inline function is even better though.\n\n[ mingo: Refined the changelog some more \u0026 added __always_inline. ]",
"id": "GHSA-jpp4-rwwf-g5qm",
"modified": "2024-05-17T15:31:07Z",
"published": "2024-05-17T15:31:07Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-52659"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/325956b0173f11e98f90462be4829a8b8b0682ce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7e1471888a5e6e846e9b4d306e5327db2b58e64e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/814305b5c23cb815ada68d43019f39050472b25f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8e5647a723c49d73b9f108a8bb38e8c29d3948ea"
}
],
"schema_version": "1.4.0",
"severity": []
}