Re: [PATCH v2] KVM: arm64: Fix shift-out-of-bounds bug

From: Marc Zyngier
Date: Thu Oct 17 2024 - 04:23:21 EST


On Wed, 16 Oct 2024 19:57:01 -0700, Ilkka Koskinen wrote:
> Fix a shift-out-of-bounds bug reported by UBSAN when running
> VM with MTE enabled host kernel.
>
> UBSAN: shift-out-of-bounds in arch/arm64/kvm/sys_regs.c:1988:14
> shift exponent 33 is too large for 32-bit type 'int'
> CPU: 26 UID: 0 PID: 7629 Comm: qemu-kvm Not tainted 6.12.0-rc2 #34
> Hardware name: IEI NF5280R7/Mitchell MB, BIOS 00.00. 2024-10-12 09:28:54 10/14/2024
> Call trace:
> dump_backtrace+0xa0/0x128
> show_stack+0x20/0x38
> dump_stack_lvl+0x74/0x90
> dump_stack+0x18/0x28
> __ubsan_handle_shift_out_of_bounds+0xf8/0x1e0
> reset_clidr+0x10c/0x1c8
> kvm_reset_sys_regs+0x50/0x1c8
> kvm_reset_vcpu+0xec/0x2b0
> __kvm_vcpu_set_target+0x84/0x158
> kvm_vcpu_set_target+0x138/0x168
> kvm_arch_vcpu_ioctl_vcpu_init+0x40/0x2b0
> kvm_arch_vcpu_ioctl+0x28c/0x4b8
> kvm_vcpu_ioctl+0x4bc/0x7a8
> __arm64_sys_ioctl+0xb4/0x100
> invoke_syscall+0x70/0x100
> el0_svc_common.constprop.0+0x48/0xf0
> do_el0_svc+0x24/0x38
> el0_svc+0x3c/0x158
> el0t_64_sync_handler+0x120/0x130
> el0t_64_sync+0x194/0x198
>
> [...]

Applied to fixes, thanks!

[1/1] KVM: arm64: Fix shift-out-of-bounds bug
commit: c6c167afa090ea0451f91814e1318755a8fb8bb9

Cheers,

M.
--
Without deviation from the norm, progress is not possible.