Implement URL safe base64 coding, as specified by RFC 4648.

6 files changed, 139 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 9ee8aeae..091d6d40 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,17 @@
 2015-02-10  Niels Möller  <nisse@lysator.liu.se>
 
-	Base-64 generalization, contributed by Amos Jeffries.
+	Base-64 generalization to support RFC4648 URL safe alphabet,
+	contributed by Amos Jeffries.
+	* base64url-decode.c (base64url_decode_init): New file and
+	function.
+	* base64url-encode.c (base64url_encode_init): New file and
+	function.
+	* Makefile.in (nettle_SOURCES): Added base64url-encode.c and
+	base64url-decode.c.
+	* base64.h: Declare new functions.
+	* testsuite/base64-test.c (test_fuzz): Test base64url encoding and
+	decoding.
+
 	* base64.h (struct base64_encode_ctx): Added pointer to alphabet.
 	(struct base64_decode_ctx): Added pointer to decoding table.
 	* base64-decode.c (base64_decode_init): Initialize table pointer.
diff --git a/Makefile.in b/Makefile.in
index fce79ea2..e861b23a 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -81,6 +81,7 @@ nettle_SOURCES = aes-decrypt-internal.c aes-decrypt.c \
 		 arctwo.c arctwo-meta.c blowfish.c \
 		 base16-encode.c base16-decode.c base16-meta.c \
 		 base64-encode.c base64-decode.c base64-meta.c \
+		 base64url-encode.c base64url-decode.c \
 		 buffer.c buffer-init.c \
 		 camellia-crypt-internal.c camellia-table.c \
 		 camellia-absorb.c camellia-invert-key.c \
diff --git a/base64.h b/base64.h
index 07a8e2b7..10c4965c 100644
--- a/base64.h
+++ b/base64.h
@@ -42,12 +42,14 @@ extern "C" {
 
 /* Name mangling */
 #define base64_encode_init nettle_base64_encode_init
+#define base64url_encode_init nettle_base64url_encode_init
 #define base64_encode_single nettle_base64_encode_single
 #define base64_encode_update nettle_base64_encode_update
 #define base64_encode_final nettle_base64_encode_final
 #define base64_encode_raw nettle_base64_encode_raw
 #define base64_encode_group nettle_base64_encode_group
 #define base64_decode_init nettle_base64_decode_init
+#define base64url_decode_init nettle_base64url_decode_init
 #define base64_decode_single nettle_base64_decode_single
 #define base64_decode_update nettle_base64_decode_update
 #define base64_decode_final nettle_base64_decode_final
@@ -80,6 +82,10 @@ struct base64_encode_ctx
 void
 base64_encode_init(struct base64_encode_ctx *ctx);
 
+/* Initialize encoding context for URL safe alphabet, RFC 4648. */
+void
+base64url_encode_init(struct base64_encode_ctx *ctx);
+
 /* Encodes a single byte. Returns amount of output (always 1 or 2). */
 size_t
 base64_encode_single(struct base64_encode_ctx *ctx,
@@ -132,6 +138,10 @@ struct base64_decode_ctx
 void
 base64_decode_init(struct base64_decode_ctx *ctx);
 
+/* Initialize encoding context for URL safe alphabet, RFC 4648. */
+void
+base64url_decode_init(struct base64_decode_ctx *ctx);
+
 /* Decodes a single byte. Returns amount of output (0 or 1), or -1 on
  * errors. */
 int
diff --git a/base64url-decode.c b/base64url-decode.c
new file mode 100644
index 00000000..448d5a66
--- /dev/null
+++ b/base64url-decode.c
@@ -0,0 +1,64 @@
+/* base64url-decode.c
+
+   Copyright (C) 2015 Amos Jeffries, Niels Möller
+
+   This file is part of GNU Nettle.
+
+   GNU Nettle is free software: you can redistribute it and/or
+   modify it under the terms of either:
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at your
+       option) any later version.
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at your
+       option) any later version.
+
+   or both in parallel, as here.
+
+   GNU Nettle is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see http://www.gnu.org/licenses/.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include "base64.h"
+
+void
+base64url_decode_init(struct base64_decode_ctx *ctx)
+{
+  static const signed char base64url_decode_table[0x100] =
+    {
+      /* White space is HT, VT, FF, CR, LF and SPC */
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -2, -2, -2, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+      -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1,
+      52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -3, -1, -1,
+      -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
+      15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63,
+      -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+      41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+    };
+
+  ctx->word = ctx->bits = ctx->padding = 0;
+  ctx->table = base64url_decode_table;
+}
diff --git a/base64url-encode.c b/base64url-encode.c
new file mode 100644
index 00000000..6af33fb8
--- /dev/null
+++ b/base64url-encode.c
@@ -0,0 +1,48 @@
+/* base64url-encode.c
+
+   Copyright (C) 2015 Amos Jeffries, Niels Möller
+
+   This file is part of GNU Nettle.
+
+   GNU Nettle is free software: you can redistribute it and/or
+   modify it under the terms of either:
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at your
+       option) any later version.
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at your
+       option) any later version.
+
+   or both in parallel, as here.
+
+   GNU Nettle is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see http://www.gnu.org/licenses/.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include "base64.h"
+
+void
+base64url_encode_init(struct base64_encode_ctx *ctx)
+{
+  static const uint8_t base64url_encode_table[64] =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "abcdefghijklmnopqrstuvwxyz"
+    "0123456789-_";
+
+  ctx->word = ctx->bits = 0;
+  ctx->alphabet = base64url_encode_table;
+}
diff --git a/testsuite/base64-test.c b/testsuite/base64-test.c
index 1a1e67d6..9fe544f9 100644
--- a/testsuite/base64-test.c
+++ b/testsuite/base64-test.c
@@ -59,6 +59,10 @@ test_fuzz(void)
       base64_encode_init(&encode);
       base64_decode_init(&decode);
       test_fuzz_once(&encode, &decode, length, input);
+
+      base64url_encode_init(&encode);
+      base64url_decode_init(&decode);
+      test_fuzz_once(&encode, &decode, length, input);
     }
 }