CVE - CVE-2021-47227

CVE-ID
CVE-2021-47227	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Prevent state corruption in __fpu__restore_sig() The non-compacted slowpath uses __copy_from_user() and copies the entire user buffer into the kernel buffer, verbatim. This means that the kernel buffer may now contain entirely invalid state on which XRSTOR will #GP. validate_user_xstate_header() can detect some of that corruption, but that leaves the onus on callers to clear the buffer. Prior to XSAVES support, it was possible just to reinitialize the buffer, completely, but with supervisor states that is not longer possible as the buffer clearing code split got it backwards. Fixing that is possible but not corrupting the state in the first place is more robust. Avoid corruption of the kernel XSAVE buffer by using copy_user_to_xstate() which validates the XSAVE header contents before copying the actual states to the kernel. copy_user_to_xstate() was previously only called for compacted-format kernel buffers, but it works for both compacted and non-compacted forms. Using it for the non-compacted form is slower because of multiple __copy_from_user() operations, but that cost is less important than robust code in an already slow path. [ Changelog polished by Dave Hansen ]
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/076f732b16a5bf842686e1b43ab6021a2d98233e URL:https://git.kernel.org/stable/c/076f732b16a5bf842686e1b43ab6021a2d98233e MISC:https://git.kernel.org/stable/c/484cea4f362e1eeb5c869abbfb5f90eae6421b38 URL:https://git.kernel.org/stable/c/484cea4f362e1eeb5c869abbfb5f90eae6421b38 MISC:https://git.kernel.org/stable/c/ec25ea1f3f05d6f8ee51d1277efea986eafd4f2a URL:https://git.kernel.org/stable/c/ec25ea1f3f05d6f8ee51d1277efea986eafd4f2a
Assigning CNA
kernel.org
Date Record Created
20240410	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240410)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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