[PATCH 0/2] platform/x86/intel/uncore-freq: String handling improvements

[PATCH 0/2] platform/x86/intel/uncore-freq: String handling improvements

[Kaushlendra Kumar]

This series replaces unsafe/deprecated string formatting functions in
the Intel uncore frequency driver with their safer alternatives.

Patch 1 replaces sprintf() with sysfs_emit() in sysfs show functions
for proper buffer bounds checking.

Patch 2 replaces sprintf() with snprintf() in device name formatting
to follow kernel best practices.

Kaushlendra Kumar (2):
  platform/x86/intel/uncore-freq: Replace sprintf() with snprintf()
  platform/x86/intel/uncore-freq: Replace sprintf() with sysfs_emit()

 .../uncore-frequency/uncore-frequency-common.c      | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

-- 
2.34.1

[PATCH 1/2] platform/x86/intel/uncore-freq: Replace sprintf() with snprintf()

[Kaushlendra Kumar]

Replace unbounded sprintf() calls with snprintf() to prevent potential
buffer overflows when formatting device names. While the current format
strings cannot overflow the buffer, using snprintf() follows kernel
best practices for string formatting.

Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
---
 .../x86/intel/uncore-frequency/uncore-frequency-common.c     | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
index 65897fae17df..c129dd450360 100644
--- a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
+++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
@@ -269,9 +269,10 @@ int uncore_freq_add_entry(struct uncore_data *data, int cpu)
 			goto uncore_unlock;
 
 		data->instance_id = ret;
-		sprintf(data->name, "uncore%02d", ret);
+		snprintf(data->name, sizeof(data->name), "uncore%02d", ret);
 	} else {
-		sprintf(data->name, "package_%02d_die_%02d", data->package_id, data->die_id);
+		snprintf(data->name, sizeof(data->name), "package_%02d_die_%02d",
+			 data->package_id, data->die_id);
 	}
 
 	uncore_read(data, &data->initial_min_freq_khz, UNCORE_INDEX_MIN_FREQ);
-- 
2.34.1

Re: [PATCH 1/2] platform/x86/intel/uncore-freq: Replace sprintf() with snprintf()

[Ilpo Järvinen]

On Tue, 30 Dec 2025, Kaushlendra Kumar wrote:

> Replace unbounded sprintf() calls with snprintf() to prevent potential
> buffer overflows when formatting device names. While the current format
> strings cannot overflow the buffer, using snprintf() follows kernel
> best practices for string formatting.
> 
> Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
> ---
>  .../x86/intel/uncore-frequency/uncore-frequency-common.c     | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
> index 65897fae17df..c129dd450360 100644
> --- a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
> +++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
> @@ -269,9 +269,10 @@ int uncore_freq_add_entry(struct uncore_data *data, int cpu)
>  			goto uncore_unlock;
>  
>  		data->instance_id = ret;
> -		sprintf(data->name, "uncore%02d", ret);
> +		snprintf(data->name, sizeof(data->name), "uncore%02d", ret);
>  	} else {
> -		sprintf(data->name, "package_%02d_die_%02d", data->package_id, data->die_id);
> +		snprintf(data->name, sizeof(data->name), "package_%02d_die_%02d",
> +			 data->package_id, data->die_id);
>  	}
>  
>  	uncore_read(data, &data->initial_min_freq_khz, UNCORE_INDEX_MIN_FREQ);

Hi,

Thanks for the patch. Please use scnprintf() instead. You don't use the 
return value so the distinction doesn't make a difference but it would be 
useful to eventually only have one of them remaining, which should be 
scnprintf() that gives a more sane return value than snprintf().

-- 
 i.

RE: [PATCH 1/2] platform/x86/intel/uncore-freq: Replace sprintf() with snprintf()

[Kumar, Kaushlendra]

On Tue, 30 Dec 2025, Ilpo Järvinen wrote:

> Hi,
> 
> Thanks for the patch. Please use scnprintf() instead. You don't use the 
> return value so the distinction doesn't make a difference but it would be 
> useful to eventually only have one of them remaining, which should be
> scnprintf() that gives a more sane return value than snprintf().

Hi Ilpo,

Thank you for the review. I'll switch to scnprintf() and send v2.

Thanks,
Kaushlendra

[PATCH 2/2] platform/x86/intel/uncore-freq: Replace sprintf() with sysfs_emit()

[Kaushlendra Kumar]

Replace sprintf() with sysfs_emit() in sysfs show functions. The
sysfs_emit() function is the preferred way to format sysfs output as
it ensures proper buffer bounds checking and correct return values.

Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
---
 .../x86/intel/uncore-frequency/uncore-frequency-common.c  | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
index c129dd450360..ff97e3d210ab 100644
--- a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
+++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
@@ -26,21 +26,21 @@ static ssize_t show_domain_id(struct kobject *kobj, struct kobj_attribute *attr,
 {
 	struct uncore_data *data = container_of(attr, struct uncore_data, domain_id_kobj_attr);
 
-	return sprintf(buf, "%u\n", data->domain_id);
+	return sysfs_emit(buf, "%u\n", data->domain_id);
 }
 
 static ssize_t show_fabric_cluster_id(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct uncore_data *data = container_of(attr, struct uncore_data, fabric_cluster_id_kobj_attr);
 
-	return sprintf(buf, "%u\n", data->cluster_id);
+	return sysfs_emit(buf, "%u\n", data->cluster_id);
 }
 
 static ssize_t show_package_id(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	struct uncore_data *data = container_of(attr, struct uncore_data, package_id_kobj_attr);
 
-	return sprintf(buf, "%u\n", data->package_id);
+	return sysfs_emit(buf, "%u\n", data->package_id);
 }
 
 #define MAX_UNCORE_AGENT_TYPES	4
@@ -77,7 +77,7 @@ static ssize_t show_attr(struct uncore_data *data, char *buf, enum uncore_index
 	if (ret)
 		return ret;
 
-	return sprintf(buf, "%u\n", value);
+	return sysfs_emit(buf, "%u\n", value);
 }
 
 static ssize_t store_attr(struct uncore_data *data, const char *buf, ssize_t count,
-- 
2.34.1