bugfix: in decode_n for base64, count down inlen before breaking when

we hit the null terminator for a string in a STRING_LIST

src/base64.c

@@ -60,12 +60,16 @@ decode(char *restrict *restrict dest, char *restrict const buf,
 {
 	char *d;
 
-	if (n <= 1)
+	if (n <= 1) {
+		errno = EINVAL;
 		return -1;
+	}
 	d = *dest;
 	for (int i = 0; i < n - 1; i++) {
-		if (d == buf + buflen)
+		if (d == buf + buflen) {
+			errno = ENOMEM;
 			return -1;
+		}
 		*d++ = (u >> 16) & 0xff;
 		u <<= 8;
 	}
@@ -154,19 +158,17 @@ base64_decode(const enum encoding dec, char *restrict const buf,
 					continue;
 				}
 				u |= (unsigned) b;
-				if (!*s)
-					break;
 				if (inlen != -1) {
 					--inlen;
 					if (inlen == 0)
 						break;
 				}
+				if (!*s)
+					break;
 			}
 			if (n == 4) {
-				if (decode(&dest, buf, buflen, u, n-term) < 0) {
-					errno = ENOMEM;
+				if (decode(&dest, buf, buflen, u, n-term) < 0)
 					return -1;
-				}
 				n = 0;
 			}
 		}
@@ -176,10 +178,8 @@ base64_decode(const enum encoding dec, char *restrict const buf,
 	if (n) {
 		if (!alpha->padding)
 			u <<= 6 * (4 - n);
-		if (decode(&dest, buf, buflen, u, n-term) < 0) {
-			errno = ENOMEM;
+		if (decode(&dest, buf, buflen, u, n-term) < 0)
 			return -1;
-		}
 	}
 
 	return dest - buf;