virt: sev-guest: Do not use host-controlled page order in cleanup path
When issuing an extended guest request (SVM_VMGEXIT_EXT_GUEST_REQUEST),
get_ext_report() allocates a buffer to retrieve a certificate blob from the
host, keeping track of its size in report_req->certs_len.
However, the host may return SNP_GUEST_VMM_ERR_INVALID_LEN, indicating
an invalid buffer size, as well as the expected length of such buffer.
get_ext_report() subsequently updates report_req->certs_len with the
host-controlled value, and cleans up the buffer by computing a page order
from such value. This is incorrect, as the host-provided length may not
match the page order of the original allocation, potentially resulting
in corruption in the page allocator.
Fix this by using alloc_pages_exact() instead, and reusing @npages to
compute the size passed to free_pages_exact(). For consistency, also
use @npages to compute the size when allocating the pages, even though
this last change has no functional effect.
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No vendor fix or workaround currently provided.
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Tracking
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Sun, 28 Jun 2026 08:00:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
cvssV3_1
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Fri, 26 Jun 2026 04:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-239 CWE-787 |
Fri, 26 Jun 2026 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-131 | |
| References |
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Wed, 24 Jun 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-239 CWE-787 |
Wed, 24 Jun 2026 17:15:00 +0000
| Type | Values Removed | Values Added |
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| Description | In the Linux kernel, the following vulnerability has been resolved: virt: sev-guest: Do not use host-controlled page order in cleanup path When issuing an extended guest request (SVM_VMGEXIT_EXT_GUEST_REQUEST), get_ext_report() allocates a buffer to retrieve a certificate blob from the host, keeping track of its size in report_req->certs_len. However, the host may return SNP_GUEST_VMM_ERR_INVALID_LEN, indicating an invalid buffer size, as well as the expected length of such buffer. get_ext_report() subsequently updates report_req->certs_len with the host-controlled value, and cleans up the buffer by computing a page order from such value. This is incorrect, as the host-provided length may not match the page order of the original allocation, potentially resulting in corruption in the page allocator. Fix this by using alloc_pages_exact() instead, and reusing @npages to compute the size passed to free_pages_exact(). For consistency, also use @npages to compute the size when allocating the pages, even though this last change has no functional effect. | |
| Title | virt: sev-guest: Do not use host-controlled page order in cleanup path | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-06-28T06:37:21.090Z
Reserved: 2026-06-09T07:44:35.373Z
Link: CVE-2026-52959
No data.
No data.
OpenCVE Enrichment
Updated: 2026-06-28T13:45:06Z