i2c: strncpy does not null terminate string

With sizeof(string) - 1 strncpy() will null terminate the string.

Signed-off-by Roel Kluin <[email protected]>

---
To test this:

#include <stdio.h>
#include <string.h>

char a[10];
char b[10];

int main()

{
        const char* str = "0123456789012";
        strncpy(a, str, sizeof(a));
        strncpy(b, str, sizeof(b) - 1);
        printf("String a was %s, b was %s\n", a, b);

        return 0;
}

drivers/i2c/busses/i2c-omap.c +0 -0

index fdd8327..bede75d 100644

Quoted 19 lines · Roel Kluin

With sizeof(string) - 1 strncpy() will null terminate the string.

Signed-off-by Roel Kluin <[email protected]>

---
To test this:

#include <stdio.h>
#include <string.h>

char a[10];
char b[10];

int main()

{
        const char* str = "0123456789012";
        strncpy(a, str, sizeof(a));
        strncpy(b, str, sizeof(b) - 1);
        printf("String a was %s, b was %s\n", a, b);

Quoted 2 lines

        return 0;
}

drivers/i2c/busses/i2c-omap.c omap_i2c_probe(struct platform_device *pdev) · line 884

Quoted 13 lines

drivers/i2c/busses/i2c-omap.c +1 -1

index fdd8327..bede75d 100644
@@ -879,7 +879,7 @@ omap_i2c_probe(struct platform_device *pdev)
 	i2c_set_adapdata(adap, dev);
 	adap->owner = THIS_MODULE;
 	adap->class = I2C_CLASS_HWMON;
-	strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
+	strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name) - 1);
 	adap->algo = &omap_i2c_algo;
 	adap->dev.parent = &pdev->dev;

Nack, please just use strlcpy() instead.

IMHO strncpy() should be banned from the kernel.