[PATCH v2 1/2] misc: amd-sbi: Address potential integer overflow issue reported in smatch

[PATCH v2 1/2] misc: amd-sbi: Address potential integer overflow issue reported in smatch

[Akshay Gupta]

Smatch warnings are reported for below commit,

Commit bb13a84ed6b7 ("misc: amd-sbi: Add support for CPUID protocol")
from Apr 28, 2025 (linux-next), leads to the following Smatch static
checker warning:

drivers/misc/amd-sbi/rmi-core.c:132 rmi_cpuid_read() warn: bitwise OR is zero '0xffffffff00000000 & 0xffff'
drivers/misc/amd-sbi/rmi-core.c:132 rmi_cpuid_read() warn: potential integer overflow from user 'msg->cpu_in_out << 32'
drivers/misc/amd-sbi/rmi-core.c:213 rmi_mca_msr_read() warn: bitwise OR is zero '0xffffffff00000000 & 0xffff'
drivers/misc/amd-sbi/rmi-core.c:213 rmi_mca_msr_read() warn: potential integer overflow from user 'msg->mcamsr_in_out << 32'

CPUID thread data from input is available at byte 4 & 5, this
patch fixes to copy the user data correctly in the argument.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/aDVyO8ByVsceybk9@stanley.mountain/
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Signed-off-by: Akshay Gupta <akshay.gupta@amd.com>
---
Changes from v1:
 - Split patch as per Greg's suggestion

 drivers/misc/amd-sbi/rmi-core.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c
index b653a21a909e..3570f3b269a9 100644
--- a/drivers/misc/amd-sbi/rmi-core.c
+++ b/drivers/misc/amd-sbi/rmi-core.c
@@ -42,7 +42,6 @@
 #define RD_MCA_CMD	0x86
 
 /* CPUID MCAMSR mask & index */
-#define CPUID_MCA_THRD_MASK	GENMASK(15, 0)
 #define CPUID_MCA_THRD_INDEX	32
 #define CPUID_MCA_FUNC_MASK	GENMASK(31, 0)
 #define CPUID_EXT_FUNC_INDEX	56
@@ -129,7 +128,7 @@ static int rmi_cpuid_read(struct sbrmi_data *data,
 		goto exit_unlock;
 	}
 
-	thread = msg->cpu_in_out << CPUID_MCA_THRD_INDEX & CPUID_MCA_THRD_MASK;
+	thread = msg->cpu_in_out >> CPUID_MCA_THRD_INDEX;
 
 	/* Thread > 127, Thread128 CS register, 1'b1 needs to be set to 1 */
 	if (thread > 127) {
@@ -210,7 +209,7 @@ static int rmi_mca_msr_read(struct sbrmi_data *data,
 		goto exit_unlock;
 	}
 
-	thread = msg->mcamsr_in_out << CPUID_MCA_THRD_INDEX & CPUID_MCA_THRD_MASK;
+	thread = msg->mcamsr_in_out >> CPUID_MCA_THRD_INDEX;
 
 	/* Thread > 127, Thread128 CS register, 1'b1 needs to be set to 1 */
 	if (thread > 127) {
-- 
2.25.1

[PATCH v2 2/2] misc: amd-sbi: Address copy_to/from_user() warning reported in smatch

[Akshay Gupta]

Smatch warnings are reported for below commit,

Commit bb13a84ed6b7 ("misc: amd-sbi: Add support for CPUID protocol")
from Apr 28, 2025 (linux-next), leads to the following Smatch static
checker warning:

drivers/misc/amd-sbi/rmi-core.c:376 apml_rmi_reg_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
drivers/misc/amd-sbi/rmi-core.c:394 apml_mailbox_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
drivers/misc/amd-sbi/rmi-core.c:411 apml_cpuid_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
drivers/misc/amd-sbi/rmi-core.c:428 apml_mcamsr_xfer() warn: maybe return -EFAULT instead of the bytes remaining?

copy_to/from_user() returns number of bytes, not copied.
In case data not copied, return "-EFAULT".

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/aDVyO8ByVsceybk9@stanley.mountain/
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Signed-off-by: Akshay Gupta <akshay.gupta@amd.com>
---
Changes from v1:
 - Split patch as per Greg's suggestion
 drivers/misc/amd-sbi/rmi-core.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c
index 3570f3b269a9..9048517c088c 100644
--- a/drivers/misc/amd-sbi/rmi-core.c
+++ b/drivers/misc/amd-sbi/rmi-core.c
@@ -372,7 +372,8 @@ static int apml_rmi_reg_xfer(struct sbrmi_data *data,
 	mutex_unlock(&data->lock);
 
 	if (msg.rflag && !ret)
-		return copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg));
+		if (copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg)))
+			return -EFAULT;
 	return ret;
 }
 
@@ -390,7 +391,9 @@ static int apml_mailbox_xfer(struct sbrmi_data *data, struct apml_mbox_msg __use
 	if (ret && ret != -EPROTOTYPE)
 		return ret;
 
-	return copy_to_user(arg, &msg, sizeof(struct apml_mbox_msg));
+	if (copy_to_user(arg, &msg, sizeof(struct apml_mbox_msg)))
+		return -EFAULT;
+	return ret;
 }
 
 static int apml_cpuid_xfer(struct sbrmi_data *data, struct apml_cpuid_msg __user *arg)
@@ -407,7 +410,9 @@ static int apml_cpuid_xfer(struct sbrmi_data *data, struct apml_cpuid_msg __user
 	if (ret && ret != -EPROTOTYPE)
 		return ret;
 
-	return copy_to_user(arg, &msg, sizeof(struct apml_cpuid_msg));
+	if (copy_to_user(arg, &msg, sizeof(struct apml_cpuid_msg)))
+		return -EFAULT;
+	return ret;
 }
 
 static int apml_mcamsr_xfer(struct sbrmi_data *data, struct apml_mcamsr_msg __user *arg)
@@ -424,7 +429,9 @@ static int apml_mcamsr_xfer(struct sbrmi_data *data, struct apml_mcamsr_msg __us
 	if (ret && ret != -EPROTOTYPE)
 		return ret;
 
-	return copy_to_user(arg, &msg, sizeof(struct apml_mcamsr_msg));
+	if (copy_to_user(arg, &msg, sizeof(struct apml_mcamsr_msg)))
+		return -EFAULT;
+	return ret;
 }
 
 static long sbrmi_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
-- 
2.25.1

Re: [PATCH v2 2/2] misc: amd-sbi: Address copy_to/from_user() warning reported in smatch

[Dan Carpenter]

On Wed, Jun 25, 2025 at 11:07:07AM +0000, Akshay Gupta wrote:
> Smatch warnings are reported for below commit,
> 
> Commit bb13a84ed6b7 ("misc: amd-sbi: Add support for CPUID protocol")
> from Apr 28, 2025 (linux-next), leads to the following Smatch static
> checker warning:
> 
> drivers/misc/amd-sbi/rmi-core.c:376 apml_rmi_reg_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
> drivers/misc/amd-sbi/rmi-core.c:394 apml_mailbox_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
> drivers/misc/amd-sbi/rmi-core.c:411 apml_cpuid_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
> drivers/misc/amd-sbi/rmi-core.c:428 apml_mcamsr_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
> 
> copy_to/from_user() returns number of bytes, not copied.
> In case data not copied, return "-EFAULT".
> 
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/all/aDVyO8ByVsceybk9@stanley.mountain/
> Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
> Signed-off-by: Akshay Gupta <akshay.gupta@amd.com>
> ---
> Changes from v1:
>  - Split patch as per Greg's suggestion
>  drivers/misc/amd-sbi/rmi-core.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c
> index 3570f3b269a9..9048517c088c 100644
> --- a/drivers/misc/amd-sbi/rmi-core.c
> +++ b/drivers/misc/amd-sbi/rmi-core.c
> @@ -372,7 +372,8 @@ static int apml_rmi_reg_xfer(struct sbrmi_data *data,
>  	mutex_unlock(&data->lock);
>  
>  	if (msg.rflag && !ret)

Unrelated to this patch, but it's always better to do if (ret) {.
Do error handling not success handling etc.

> -		return copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg));
> +		if (copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg)))
> +			return -EFAULT;
>  	return ret;
>  }
>  
> @@ -390,7 +391,9 @@ static int apml_mailbox_xfer(struct sbrmi_data *data, struct apml_mbox_msg __use
>  	if (ret && ret != -EPROTOTYPE)
>  		return ret;
>  
> -	return copy_to_user(arg, &msg, sizeof(struct apml_mbox_msg));
> +	if (copy_to_user(arg, &msg, sizeof(struct apml_mbox_msg)))
> +		return -EFAULT;
> +	return ret;

This fixes the -EPROTOTYPE as well.  In the original code, it would
return success where -EPROTOTYPE was intended.  It's probably worth
mentioning that in the commit message and maybe adding a test cases to
your test platform.

regards,
dan carpenter

Re: [PATCH v2 2/2] misc: amd-sbi: Address copy_to/from_user() warning reported in smatch

[Gupta, Akshay]

On 6/25/2025 5:13 PM, Dan Carpenter wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> On Wed, Jun 25, 2025 at 11:07:07AM +0000, Akshay Gupta wrote:
>> Smatch warnings are reported for below commit,
>>
>> Commit bb13a84ed6b7 ("misc: amd-sbi: Add support for CPUID protocol")
>> from Apr 28, 2025 (linux-next), leads to the following Smatch static
>> checker warning:
>>
>> drivers/misc/amd-sbi/rmi-core.c:376 apml_rmi_reg_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
>> drivers/misc/amd-sbi/rmi-core.c:394 apml_mailbox_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
>> drivers/misc/amd-sbi/rmi-core.c:411 apml_cpuid_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
>> drivers/misc/amd-sbi/rmi-core.c:428 apml_mcamsr_xfer() warn: maybe return -EFAULT instead of the bytes remaining?
>>
>> copy_to/from_user() returns number of bytes, not copied.
>> In case data not copied, return "-EFAULT".
>>
>> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
>> Closes: https://lore.kernel.org/all/aDVyO8ByVsceybk9@stanley.mountain/
>> Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
>> Signed-off-by: Akshay Gupta <akshay.gupta@amd.com>
>> ---
>> Changes from v1:
>>   - Split patch as per Greg's suggestion
>>   drivers/misc/amd-sbi/rmi-core.c | 15 +++++++++++----
>>   1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/misc/amd-sbi/rmi-core.c b/drivers/misc/amd-sbi/rmi-core.c
>> index 3570f3b269a9..9048517c088c 100644
>> --- a/drivers/misc/amd-sbi/rmi-core.c
>> +++ b/drivers/misc/amd-sbi/rmi-core.c
>> @@ -372,7 +372,8 @@ static int apml_rmi_reg_xfer(struct sbrmi_data *data,
>>        mutex_unlock(&data->lock);
>>
>>        if (msg.rflag && !ret)
> Unrelated to this patch, but it's always better to do if (ret) {.
> Do error handling not success handling etc.

Hi Dan,

Thank you for the suggestion, will take care of this.

>> -             return copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg));
>> +             if (copy_to_user(arg, &msg, sizeof(struct apml_reg_xfer_msg)))
>> +                     return -EFAULT;
>>        return ret;
>>   }
>>
>> @@ -390,7 +391,9 @@ static int apml_mailbox_xfer(struct sbrmi_data *data, struct apml_mbox_msg __use
>>        if (ret && ret != -EPROTOTYPE)
>>                return ret;
>>
>> -     return copy_to_user(arg, &msg, sizeof(struct apml_mbox_msg));
>> +     if (copy_to_user(arg, &msg, sizeof(struct apml_mbox_msg)))
>> +             return -EFAULT;
>> +     return ret;
> This fixes the -EPROTOTYPE as well.  In the original code, it would
> return success where -EPROTOTYPE was intended.  It's probably worth
> mentioning that in the commit message and maybe adding a test cases to
> your test platform.
I will update the commit message to address this.
> regards,
> dan carpenter
>