[PATCH] x86/sgx: Add overflow check in sgx_validate_offset_length()

[PATCH] x86/sgx: Add overflow check in sgx_validate_offset_length()

[Borys]

sgx_validate_offset_length() function verifies "offset" and "length"
arguments provided by userspace, but was missing an overflow check on
their addition.
This code was originally introduced in commit c6d26d370767 ("x86/sgx:
Add SGX_IOC_ENCLAVE_ADD_PAGES") and later refactored in commit
dda03e2c331b ("x86/sgx: Create utility to validate user provided offset
and length").

Fixes: c6d26d370767 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES")
Signed-off-by: Borys Popławski <borysp@invisiblethingslab.com>
---
 Applies on top of tip/x86/sgx ee56a283988d739c25d2d00ffb22707cb487ab47

 arch/x86/kernel/cpu/sgx/ioctl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index ebe79d60619f..da8b8ea6b063 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -356,6 +356,9 @@ static int sgx_validate_offset_length(struct sgx_encl *encl,
 	if (!length || !IS_ALIGNED(length, PAGE_SIZE))
 		return -EINVAL;
 
+	if (offset + length < offset)
+		return -EINVAL;
+
 	if (offset + length - PAGE_SIZE >= encl->size)
 		return -EINVAL;
 
-- 
2.37.3

Re: [PATCH] x86/sgx: Add overflow check in sgx_validate_offset_length()

[Jarkko Sakkinen]

On Wed, Oct 05, 2022 at 12:59:03AM +0200, Borys wrote:
> sgx_validate_offset_length() function verifies "offset" and "length"
> arguments provided by userspace, but was missing an overflow check on
> their addition.
> This code was originally introduced in commit c6d26d370767 ("x86/sgx:
> Add SGX_IOC_ENCLAVE_ADD_PAGES") and later refactored in commit
> dda03e2c331b ("x86/sgx: Create utility to validate user provided offset
> and length").
> 
> Fixes: c6d26d370767 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES")
> Signed-off-by: Borys Popławski <borysp@invisiblethingslab.com>
> ---
>  Applies on top of tip/x86/sgx ee56a283988d739c25d2d00ffb22707cb487ab47
> 
>  arch/x86/kernel/cpu/sgx/ioctl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> index ebe79d60619f..da8b8ea6b063 100644
> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -356,6 +356,9 @@ static int sgx_validate_offset_length(struct sgx_encl *encl,
>  	if (!length || !IS_ALIGNED(length, PAGE_SIZE))
>  		return -EINVAL;
>  
> +	if (offset + length < offset)
> +		return -EINVAL;
> +
>  	if (offset + length - PAGE_SIZE >= encl->size)
>  		return -EINVAL;
>  
> -- 
> 2.37.3
> 

Thank you.

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BTW, needs:

Cc: stable@vger.kernel.org # v5.11+

BR, Jarkko

Re: [PATCH] x86/sgx: Add overflow check in sgx_validate_offset_length()

[Reinette Chatre]

(Move x86 maintainers to "To:")

Hi Maintainers,

Could you please consider this fix for inclusion?

Thank you very much

Reinette

On 10/4/2022 4:15 PM, Jarkko Sakkinen wrote:
> On Wed, Oct 05, 2022 at 12:59:03AM +0200, Borys wrote:
>> sgx_validate_offset_length() function verifies "offset" and "length"
>> arguments provided by userspace, but was missing an overflow check on
>> their addition.
>> This code was originally introduced in commit c6d26d370767 ("x86/sgx:
>> Add SGX_IOC_ENCLAVE_ADD_PAGES") and later refactored in commit
>> dda03e2c331b ("x86/sgx: Create utility to validate user provided offset
>> and length").
>>
>> Fixes: c6d26d370767 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES")
>> Signed-off-by: Borys Popławski <borysp@invisiblethingslab.com>
>> ---
>>  Applies on top of tip/x86/sgx ee56a283988d739c25d2d00ffb22707cb487ab47
>>
>>  arch/x86/kernel/cpu/sgx/ioctl.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
>> index ebe79d60619f..da8b8ea6b063 100644
>> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
>> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
>> @@ -356,6 +356,9 @@ static int sgx_validate_offset_length(struct sgx_encl *encl,
>>  	if (!length || !IS_ALIGNED(length, PAGE_SIZE))
>>  		return -EINVAL;
>>  
>> +	if (offset + length < offset)
>> +		return -EINVAL;
>> +
>>  	if (offset + length - PAGE_SIZE >= encl->size)
>>  		return -EINVAL;
>>  
>> -- 
>> 2.37.3
>>
> 
> Thank you.
> 
> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> 
> BTW, needs:
> 
> Cc: stable@vger.kernel.org # v5.11+
> 
> BR, Jarkko

[tip: x86/urgent] x86/sgx: Add overflow check in sgx_validate_offset_length()

[tip-bot2 for Borys Popławski]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     f0861f49bd946ff94fce4f82509c45e167f63690
Gitweb:        https://git.kernel.org/tip/f0861f49bd946ff94fce4f82509c45e167f63690
Author:        Borys Popławski <borysp@invisiblethingslab.com>
AuthorDate:    Wed, 05 Oct 2022 00:59:03 +02:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Tue, 08 Nov 2022 20:34:05 +01:00

x86/sgx: Add overflow check in sgx_validate_offset_length()

sgx_validate_offset_length() function verifies "offset" and "length"
arguments provided by userspace, but was missing an overflow check on
their addition. Add it.

Fixes: c6d26d370767 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES")
Signed-off-by: Borys Popławski <borysp@invisiblethingslab.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Cc: stable@vger.kernel.org # v5.11+
Link: https://lore.kernel.org/r/0d91ac79-6d84-abed-5821-4dbe59fa1a38@invisiblethingslab.com
---
 arch/x86/kernel/cpu/sgx/ioctl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index ebe79d6..da8b8ea 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -356,6 +356,9 @@ static int sgx_validate_offset_length(struct sgx_encl *encl,
 	if (!length || !IS_ALIGNED(length, PAGE_SIZE))
 		return -EINVAL;
 
+	if (offset + length < offset)
+		return -EINVAL;
+
 	if (offset + length - PAGE_SIZE >= encl->size)
 		return -EINVAL;