Klocwork: Fix the Null pointer derefernce found by klocwork

Signed-off-by: Thejaswani Putta <thejaswani.putta@intel.com>
Change-Id: I15973ac28e9645826986cf63d2160eedb83024e4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32290
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Lijian Zhao <lijian.zhao@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/lib/string.c

@@ -6,7 +6,8 @@ char *strdup(const char *s)
 {
 	size_t sz = strlen(s) + 1;
 	char *d = malloc(sz);
-	memcpy(d, s, sz);
+	if (d)
+		memcpy(d, s, sz);
 	return d;
 }
 
@@ -15,7 +16,9 @@ char *strconcat(const char *s1, const char *s2)
 	size_t sz_1 = strlen(s1);
 	size_t sz_2 = strlen(s2);
 	char *d = malloc(sz_1 + sz_2 + 1);
-	memcpy(d, s1, sz_1);
-	memcpy(d + sz_1, s2, sz_2 + 1);
+	if (d) {
+		memcpy(d, s1, sz_1);
+		memcpy(d + sz_1, s2, sz_2 + 1);
+	}
 	return d;
 }