[PATCH] hwmon: (ibmpowernv) Use scnprintf() for avoiding potential buffer overflow

Takashi Iwai tiwai at suse.de
Wed Mar 11 18:39:44 AEDT 2020


Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 drivers/hwmon/ibmpowernv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/ibmpowernv.c b/drivers/hwmon/ibmpowernv.c
index 0e525cfbdfc5..a750647e66a4 100644
--- a/drivers/hwmon/ibmpowernv.c
+++ b/drivers/hwmon/ibmpowernv.c
@@ -186,7 +186,7 @@ static void make_sensor_label(struct device_node *np,
 	u32 id;
 	size_t n;
 
-	n = snprintf(sdata->label, sizeof(sdata->label), "%s", label);
+	n = scnprintf(sdata->label, sizeof(sdata->label), "%s", label);
 
 	/*
 	 * Core temp pretty print
@@ -199,11 +199,11 @@ static void make_sensor_label(struct device_node *np,
 			 * The digital thermal sensors are associated
 			 * with a core.
 			 */
-			n += snprintf(sdata->label + n,
+			n += scnprintf(sdata->label + n,
 				      sizeof(sdata->label) - n, " %d",
 				      cpuid);
 		else
-			n += snprintf(sdata->label + n,
+			n += scnprintf(sdata->label + n,
 				      sizeof(sdata->label) - n, " phy%d", id);
 	}
 
@@ -211,7 +211,7 @@ static void make_sensor_label(struct device_node *np,
 	 * Membuffer pretty print
 	 */
 	if (!of_property_read_u32(np, "ibm,chip-id", &id))
-		n += snprintf(sdata->label + n, sizeof(sdata->label) - n,
+		n += scnprintf(sdata->label + n, sizeof(sdata->label) - n,
 			      " %d", id & 0xffff);
 }
 
-- 
2.16.4



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