CVE - CVE-2024-50102

CVE-ID
CVE-2024-50102	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: fix user address masking non-canonical speculation issue It turns out that AMD has a "Meltdown Lite(tm)" issue with non-canonical accesses in kernel space. And so using just the high bit to decide whether an access is in user space or kernel space ends up with the good old "leak speculative data" if you have the right gadget using the result: CVE-2020-12965 “Transient Execution of Non-Canonical Accesses“ Now, the kernel surrounds the access with a STAC/CLAC pair, and those instructions end up serializing execution on older Zen architectures, which closes the speculation window. But that was true only up until Zen 5, which renames the AC bit [1]. That improves performance of STAC/CLAC a lot, but also means that the speculation window is now open. Note that this affects not just the new address masking, but also the regular valid_user_address() check used by access_ok(), and the asm version of the sign bit check in the get_user() helpers. It does not affect put_user() or clear_user() variants, since there's no speculative result to be used in a gadget for those operations.
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/291313693677a345d4f50aae3c68e28b469f601e URL:https://git.kernel.org/stable/c/291313693677a345d4f50aae3c68e28b469f601e MISC:https://git.kernel.org/stable/c/86e6b1547b3d013bc392adf775b89318441403c2 URL:https://git.kernel.org/stable/c/86e6b1547b3d013bc392adf775b89318441403c2
Assigning CNA
kernel.org
Date Record Created
20241021	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 (20241021)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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