lib: sbi: Fix potential garbage data in string copy functions

In the original implementation of `sbi_strcpy` and `sbi_strncpy`, if the
destination buffer (`dest`) was longer than the source string (`src`),
the functions did not ensure that the remaining bytes in `dest` were
properly null-terminated. This could result in garbage data being
present in the destination buffer after the copy operation, as the
functions only copied characters from `src` without explicitly
terminating `dest`.

Signed-off-by: Dongdong Zhang <zhangdongdong@eswincomputing.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

lib/sbi/sbi_string.c

@@ -68,22 +68,22 @@ char *sbi_strcpy(char *dest, const char *src)
 {
 	char *ret = dest;
 
-	while (*src != '\0') {
+	while ((*dest++ = *src++) != '\0') {
-		*dest++ = *src++;
 	}
-
 	return ret;
 }
 
 char *sbi_strncpy(char *dest, const char *src, size_t count)
 {
-	char *ret = dest;
+	char *tmp = dest;
 
-	while (count-- && *src != '\0') {
+	while (count) {
-		*dest++ = *src++;
+		if ((*tmp = *src) != 0)
+			src++;
+		tmp++;
+		count--;
 	}
-
+	return dest;
-	return ret;
 }
 
 char *sbi_strchr(const char *s, int c)