cbcvebase.
CVE-2024-50275
published 2024-11-19

CVE-2024-50275: In the Linux kernel, the following vulnerability has been resolved: arm64/sve: Discard stale CPU state when handling SVE traps The logic for handling SVE traps…

PriorityP429high7CVSS 3.1
AVLACHPRLUINSUCHIHAH
EPSS
0.24%
15.1th percentile
In the Linux kernel, the following vulnerability has been resolved: arm64/sve: Discard stale CPU state when handling SVE traps The logic for handling SVE traps manipulates saved FPSIMD/SVE state incorrectly, and a race with preemption can result in a task having TIF_SVE set and TIF_FOREIGN_FPSTATE clear even though the live CPU state is stale (e.g. with SVE traps enabled). This has been observed to result in warnings from do_sve_acc() where SVE traps are not expected while TIF_SVE is set: | if (test_and_set_thread_flag(TIF_SVE)) | WARN_ON(1); /* SVE access shouldn't have trapped */ Warnings of this form have been reported intermittently, e.g. https://lore.kernel.org/linux-arm-kernel/CA+G9fYtEGe_DhY2Ms7+L7NKsLYUomGsgqpdBj+QwDLeSg=JhGg@mail.gmail.com/ https://lore.kernel.org/linux-arm-kernel/[email protected]/ The race can occur when the SVE trap handler is preempted before and after manipulating the saved FPSIMD/SVE state, starting and ending on the same CPU, e.g. | void do_sve_acc(unsigned long esr, struct pt_regs *regs) | { | // Trap on CPU 0 with TIF_SVE clear, SVE traps enabled | // task->fpsimd_cpu is 0. | // per_cpu_ptr(&fpsimd_last_state, 0) is task. | | ... | | // Preempted; migrated from CPU 0 to CPU 1. | // TIF_FOREIGN_FPSTATE is set. | | get_cpu_fpsimd_context(); | | if (test_and_set_thread_flag(TIF_SVE)) | WARN_ON(1); /* SVE access shouldn't have trapped */ | | sve_init_regs() { | if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { | ... | } else { | fpsimd_to_sve(current); | current->thread.fp_type = FP_STATE_SVE; | } | } | | put_cpu_fpsimd_context(); | | // Preempted; migrated from CPU 1 to CPU 0. | // task->fpsimd_cpu is still 0 | // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then: | // - Stale HW state is reused (with SVE traps enabled) | // - TIF_FOREIGN_FPSTATE is cleared | // - A return to userspace skips HW state restore | } Fix the case where the state is not live and TIF_FOREIGN_FPSTATE is set by calling fpsimd_f

Affected

26 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
debianlinux-6.1< linux 6.1.123-1 (bookworm)linux 6.1.123-1 (bookworm)
linuxlinux
linuxlinux>= cccb78ce89c45a4414db712be4986edfb92434bd < 51d3d80a6dc314982a9a0aeb0961085922a1aa1551d3d80a6dc314982a9a0aeb0961085922a1aa15
linuxlinux>= cccb78ce89c45a4414db712be4986edfb92434bd < de529504b3274d57caf8f66800b714b0d3ee235ade529504b3274d57caf8f66800b714b0d3ee235a
linuxlinux>= cccb78ce89c45a4414db712be4986edfb92434bd < 51d11ea0250d6ee461987403bbfd4b2abb5613a751d11ea0250d6ee461987403bbfd4b2abb5613a7
linuxlinux>= cccb78ce89c45a4414db712be4986edfb92434bd < fa9ce027b3ce37a2bb173bf2553b5caa438fd8c9fa9ce027b3ce37a2bb173bf2553b5caa438fd8c9
linuxlinux>= cccb78ce89c45a4414db712be4986edfb92434bd < 751ecf6afd6568adc98f2a6052315552c0483d18751ecf6afd6568adc98f2a6052315552c0483d18
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.1.123-16.1.123-1
linuxlinux_kernel>= 0 < 6.11.9-16.11.9-1
linuxlinux_kernel>= 0 < 6.11.9-16.11.9-1
linuxlinux_kernel>= 0 < 5.15.0-135.1465.15.0-135.146
linuxlinux_kernel>= 0 < 6.8.0-58.606.8.0-58.60
linuxlinux_kernel>= 0 < 6.11.0-18.186.11.0-18.18
linuxlinux_kernel>= 5.13 < 6.6.616.6.61
linuxlinux_kernel>= 6.7 < 6.11.86.11.8
msrcazl3_kernel_6.6.57.1-7_on_azure_linux_3.0
msrcazl3_kernel_6.6.64.2-1_on_azure_linux_3.0
msrccbl2_kernel_5.15.176.3-1_on_cbl_mariner_2.0

CVSS provenance

nvdv3.17.0HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian7.0HIGH
vendor_msrc7.0HIGH
vendor_redhat7.0HIGH
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