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.
CVSS breakdown
Affected products
- Linux / Linux3e385c0d6ce88ac9916dcf84267bd5855d830748 – 3f6fb0211b39aaa1b841260681dd02ca6b693ed5
- Linux / Linux3e385c0d6ce88ac9916dcf84267bd5855d830748 – 9e48b4f813d2c3db75d522aa82ab705ce04b7e2d
- Linux / Linux3e385c0d6ce88ac9916dcf84267bd5855d830748 – 23e6a1ca04ae44806439a5a446e62e4d42e80bb4
- Linux / Linux0b16521f95c875e79d657cb8d6911c15080dbb80 – 0b16521f95c875e79d657cb8d6911c15080dbb80
- Linux / Linux6.13.8 – 6.14
- Linux / Linux6.14 – 6.14
- Linux / Linux0 – 6.14
- Linux / Linux6.18.33 – 6.18.*
- Linux / Linux7.0.10 – 7.0.*
- Linux / Linux7.1 – *