cbcvebase.
CVE-2021-47226
published 2024-05-21

CVE-2021-47226: In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer Both Intel and AMD…

PriorityP428high7.1CVSS 3.1
AVLACLPRLUINSUCNIHAH
EPSS
0.22%
12.9th percentile
In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer Both Intel and AMD consider it to be architecturally valid for XRSTOR to fail with #PF but nonetheless change the register state. The actual conditions under which this might occur are unclear [1], but it seems plausible that this might be triggered if one sibling thread unmaps a page and invalidates the shared TLB while another sibling thread is executing XRSTOR on the page in question. __fpu__restore_sig() can execute XRSTOR while the hardware registers are preserved on behalf of a different victim task (using the fpu_fpregs_owner_ctx mechanism), and, in theory, XRSTOR could fail but modify the registers. If this happens, then there is a window in which __fpu__restore_sig() could schedule out and the victim task could schedule back in without reloading its own FPU registers. This would result in part of the FPU state that __fpu__restore_sig() was attempting to load leaking into the victim task's user-visible state. Invalidate preserved FPU registers on XRSTOR failure to prevent this situation from corrupting any state. [1] Frequent readers of the errata lists might imagine "complex microarchitectural conditions".

Affected

17 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.10.46-1 (bookworm)linux 5.10.46-1 (bookworm)
linuxlinux
linuxlinux>= 1d731e731c4cd7cbd3b1aa295f0932e7610da82f < a7748e021b9fb7739e3cb88449296539de0b6817a7748e021b9fb7739e3cb88449296539de0b6817
linuxlinux>= 1d731e731c4cd7cbd3b1aa295f0932e7610da82f < 002665dcba4bbec8c82f0aeb4bd3f44334ed2c14002665dcba4bbec8c82f0aeb4bd3f44334ed2c14
linuxlinux>= 1d731e731c4cd7cbd3b1aa295f0932e7610da82f < d8778e393afa421f1f117471144f8ce6deb6953ad8778e393afa421f1f117471144f8ce6deb6953a
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.46-15.10.46-1
linuxlinux_kernel>= 0 < 5.10.46-15.10.46-1
linuxlinux_kernel>= 0 < 5.10.46-15.10.46-1
linuxlinux_kernel>= 0 < 5.10.46-15.10.46-1
linuxlinux_kernel>= 5.11 < 5.12.135.12.13
linuxlinux_kernel>= 5.2 < 5.10.465.10.46

CVSS provenance

nvdv3.17.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
osv7.1HIGH
vendor_debian7.1HIGH
vendor_redhat7.1HIGH
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