Executive Summary
| Informations | |||
|---|---|---|---|
| Name | CVE-2025-21632 | First vendor Publication | 2025-01-19 |
| Vendor | Cve | Last vendor Modification | 2025-01-19 |
Security-Database Scoring CVSS v3
| Cvss vector : N/A | |||
|---|---|---|---|
| Overall CVSS Score | NA | ||
| Base Score | NA | Environmental Score | NA |
| impact SubScore | NA | Temporal Score | NA |
| Exploitabality Sub Score | NA | ||
| Calculate full CVSS 3.0 Vectors scores | |||
Security-Database Scoring CVSS v2
| Cvss vector : | |||
|---|---|---|---|
| Cvss Base Score | N/A | Attack Range | N/A |
| Cvss Impact Score | N/A | Attack Complexity | N/A |
| Cvss Expoit Score | N/A | Authentication | N/A |
| Calculate full CVSS 2.0 Vectors scores | |||
Detail
| In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Ensure shadow stack is active before "getting" registers The x86 shadow stack support has its own set of registers. Those registers are XSAVE-managed, but they are "supervisor state components" which means that userspace can not touch them with XSAVE/XRSTOR. It also means that they are not accessible from the existing ptrace ABI for XSAVE state. Thus, there is a new ptrace get/set interface for it. The regset code that ptrace uses provides an ->active() handler in addition to the get/set ones. For shadow stack this ->active() handler verifies that shadow stack is enabled via the ARCH_SHSTK_SHSTK bit in the thread struct. The ->active() handler is checked from some call sites of the regset get/set handlers, but not the ptrace ones. This was not understood when shadow stack support was put in place. As a result, both the set/get handlers can be called with XFEATURE_CET_USER in its init state, which would cause get_xsave_addr() to return NULL and trigger a WARN_ON(). The ssp_set() handler luckily has an ssp_active() check to avoid surprising the kernel with shadow stack behavior when the kernel is not ready for it (ARCH_SHSTK_SHSTK==0). That check just happened to avoid the warning. But the ->get() side wasn't so lucky. It can be called with shadow stacks disabled, triggering the warning in practice, as reported by Christina Schimpe: WARNING: CPU: 5 PID: 1773 at arch/x86/kernel/fpu/regset.c:198 ssp_get+0x89/0xa0 [...] Call Trace: Ensure that shadow stacks are active in a thread before looking them up in the XSAVE buffer. Since ARCH_SHSTK_SHSTK and user_ssp[SHSTK_EN] are set at the same time, the active check ensures that there will be something to find in the XSAVE buffer. [ dhansen: changelog/subject tweaks ] |
Original Source
| Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-21632 |
Sources (Detail)
Alert History
| Date | Informations |
|---|---|
| 2025-01-19 17:20:28 |
|
