bugfix base64_decode() for a concatenated STRING_LIST

src/base64.c

@@ -192,7 +192,7 @@ base64_decode(const enum encoding dec, char *restrict const buf,
 	const char *s;
 	char *dest = buf;
 	unsigned u = 0, term = 0;
-	int n;
+	int n = 0;
 
 	AN(buf);
 
@@ -204,13 +204,14 @@ base64_decode(const enum encoding dec, char *restrict const buf,
 			return -1;
 		}
 		while (*s) {
-			for (n = 0; n < 4; n++) {
+			while (n < 4) {
 				char b = alpha->i64[(unsigned) *s++];
 				u <<= 6;
 				if (b == ILLEGAL) {
 					errno = EINVAL;
 					return -1;
 				}
+				n++;
 				if (b == PAD) {
 					term++;
 					continue;
@@ -219,14 +220,16 @@ base64_decode(const enum encoding dec, char *restrict const buf,
 				if (!*s)
 					break;
 			}
-			if (n == 4)
+			if (n == 4) {
 				if (decode(&dest, buf, maxlen, u, n-term) < 0) {
 					errno = ENOMEM;
 					return -1;
 				}
+				n = 0;
+			}
 		}
 	}
-	if (n != 4)
+	if (n)
 		if (decode(&dest, buf, maxlen, u, n-term) < 0) {
 			errno = ENOMEM;
 			return -1;

src/tests/base64.vtc

@@ -49,6 +49,25 @@ varnish v1 -vcl+backend {
 	      = convert.encode(BASE64,
 			       convert.decode(BASE64, "L0hlbGxvIHdvcmxkLw=="));
 
+	    set resp.http.l = "L";
+	    set resp.http.dec2pieces
+	      = convert.encode(IDENTITY, convert.decode(BASE64,
+			       resp.http.l + "0hlbGxvIHdvcmxkLw=="));
+
+	    set resp.http.pad = "==";
+	    set resp.http.dec3pieces
+	      = convert.encode(IDENTITY, convert.decode(BASE64,
+			       resp.http.l + "0hlbGxvIHdvcmxkLw"
+			       + resp.http.pad));
+
+	    set resp.http.mid1 = "GxvI";
+	    set resp.http.mid2 = "dvcmx";
+	    set resp.http.dec7pieces
+	      = convert.encode(IDENTITY, convert.decode(BASE64,
+			       resp.http.l + "0hlb" + resp.http.mid1
+			       + "H" + resp.http.mid2 + "kLw"
+			       + resp.http.pad));
+
 	}
 } -start
 
@@ -64,6 +83,9 @@ client c1 {
 	expect resp.http.dec == "/Hello world/"
 	expect resp.http.dec2 == "The quick brown fox jumps over the lazy dog"
 	expect resp.http.decenc == "L0hlbGxvIHdvcmxkLw=="
+	expect resp.http.dec2pieces == "/Hello world/"
+	expect resp.http.dec3pieces == "/Hello world/"
+	expect resp.http.dec7pieces == "/Hello world/"
 }
 
 client c1 -run