* [PATCH] KVM: arm64: Fix shift-out-of-bounds bug
@ 2024-10-16 19:57 Ilkka Koskinen
2024-10-16 22:46 ` Gavin Shan
0 siblings, 1 reply; 3+ messages in thread
From: Ilkka Koskinen @ 2024-10-16 19:57 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, Joey Gouly, Suzuki K Poulose,
Zenghui Yu, Catalin Marinas, Will Deacon, Akihiko Odaki
Cc: linux-arm-kernel, kvmarm, linux-kernel, Ilkka Koskinen
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
Fixes: 7af0c2534f4c ("KVM: arm64: Normalize cache configuration")
Cc: stable@vger.kernel.org
Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
---
arch/arm64/kvm/sys_regs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 375052d8cd22..665c576faba3 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1994,7 +1994,7 @@ static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
* one cache line.
*/
if (kvm_has_mte(vcpu->kvm))
- clidr |= 2 << CLIDR_TTYPE_SHIFT(loc);
+ clidr |= 2UL << CLIDR_TTYPE_SHIFT(loc);
__vcpu_sys_reg(vcpu, r->reg) = clidr;
--
2.40.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] KVM: arm64: Fix shift-out-of-bounds bug
2024-10-16 19:57 [PATCH] KVM: arm64: Fix shift-out-of-bounds bug Ilkka Koskinen
@ 2024-10-16 22:46 ` Gavin Shan
2024-10-17 2:39 ` Ilkka Koskinen
0 siblings, 1 reply; 3+ messages in thread
From: Gavin Shan @ 2024-10-16 22:46 UTC (permalink / raw)
To: Ilkka Koskinen, Marc Zyngier, Oliver Upton, Joey Gouly,
Suzuki K Poulose, Zenghui Yu, Catalin Marinas, Will Deacon,
Akihiko Odaki
Cc: linux-arm-kernel, kvmarm, linux-kernel
On 10/17/24 5:57 AM, 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
>
> Fixes: 7af0c2534f4c ("KVM: arm64: Normalize cache configuration")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
> ---
> arch/arm64/kvm/sys_regs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
Reviewed-by: Gavin Shan <gshan@redhat.com>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 375052d8cd22..665c576faba3 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1994,7 +1994,7 @@ static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> * one cache line.
> */
> if (kvm_has_mte(vcpu->kvm))
> - clidr |= 2 << CLIDR_TTYPE_SHIFT(loc);
> + clidr |= 2UL << CLIDR_TTYPE_SHIFT(loc);
>
Nit: It's more precise to have 2ULL since the type of @clidr is u64,
equivalent to 'unsigned long long' on arm64. The pattern ULL has been
used in reset_mpidr().
> __vcpu_sys_reg(vcpu, r->reg) = clidr;
>
Thanks,
Gavin
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] KVM: arm64: Fix shift-out-of-bounds bug
2024-10-16 22:46 ` Gavin Shan
@ 2024-10-17 2:39 ` Ilkka Koskinen
0 siblings, 0 replies; 3+ messages in thread
From: Ilkka Koskinen @ 2024-10-17 2:39 UTC (permalink / raw)
To: Gavin Shan
Cc: Ilkka Koskinen, Marc Zyngier, Oliver Upton, Joey Gouly,
Suzuki K Poulose, Zenghui Yu, Catalin Marinas, Will Deacon,
Akihiko Odaki, linux-arm-kernel, kvmarm, linux-kernel
Hi Gavin,
On Wed, 16 Oct 2024, Gavin Shan wrote:
> On 10/17/24 5:57 AM, 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
>>
>> Fixes: 7af0c2534f4c ("KVM: arm64: Normalize cache configuration")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
>> ---
>> arch/arm64/kvm/sys_regs.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
>
>> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
>> index 375052d8cd22..665c576faba3 100644
>> --- a/arch/arm64/kvm/sys_regs.c
>> +++ b/arch/arm64/kvm/sys_regs.c
>> @@ -1994,7 +1994,7 @@ static u64 reset_clidr(struct kvm_vcpu *vcpu, const
>> struct sys_reg_desc *r)
>> * one cache line.
>> */
>> if (kvm_has_mte(vcpu->kvm))
>> - clidr |= 2 << CLIDR_TTYPE_SHIFT(loc);
>> + clidr |= 2UL << CLIDR_TTYPE_SHIFT(loc);
>>
>
> Nit: It's more precise to have 2ULL since the type of @clidr is u64,
> equivalent to 'unsigned long long' on arm64. The pattern ULL has been
> used in reset_mpidr().
That's a good catch. I change it and submit v2 right away.
Cheers, Ilkka
>
>> __vcpu_sys_reg(vcpu, r->reg) = clidr;
>>
>
> Thanks,
> Gavin
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2024-10-17 2:39 UTC | newest]
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2024-10-16 19:57 [PATCH] KVM: arm64: Fix shift-out-of-bounds bug Ilkka Koskinen
2024-10-16 22:46 ` Gavin Shan
2024-10-17 2:39 ` Ilkka Koskinen
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