On 29/01/2015 5:51 p.m., Amos Jeffries wrote:
> RFC 4648 (https://tools.ietf.org/html/rfc4648) standardizes two
> Base-64 alphabets. Nettle currently only supports the traditional
> base-64 alphabet from section 4.
>
> There is growing use amongst new protocol definitions and extensions,
> particularly in the HTTP area for the URL-safe extension alphabet
> instead of the classical Base-64 alphabet.
>
> The attached patch implements a proposed API/ABI extension adding
> support for RFC 4648 section 5 "Base 64 Encoding with URL and Filename
> Safe Alphabet"
>
> For the standardized alphabets external code simply calls the init()
> function relevant to the alphabet it is needing to encode/decode with.
> The library internally uses the context to select which lookup table to
> use for later base64 function calls.
>
> For custom or non-standard alphabets a pointer to the alphabet lookup
> table is included in the encode/decode contexts. External code can
> memset() a context to empty and provide the alphabet lookup table pointer.
>
>
> Amos Jeffries
> Treehouse Networks Ltd.
>
> PS, I have also removed the dead code wrappend in "#if 0" rather than
> updating it.
>
Meh Nix that earlier patch. Here is an updated version without the
stupid syntax errors.
This passes the base64 unit tests, but there are no specific tests for
the difference in lookup tables (and no test vectors in the RFC either).
If you want some added I can look at adding some.
Amos
diff --git a/Makefile.in b/Makefile.in
index 2a940f9..48cce47 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-decode.c b/base64-decode.c
index f622baa..b603930 100644
--- a/base64-decode.c
+++ b/base64-decode.c
@@ -43,7 +43,7 @@
#define TABLE_END -3
static const signed char
-decode_table[0x100] =
+default_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,
@@ -68,6 +68,7 @@ void
base64_decode_init(struct base64_decode_ctx *ctx)
{
ctx->word = ctx->bits = ctx->padding = 0;
+ ctx->alphabet = default_decode_table;
}
int
@@ -75,9 +76,7 @@ base64_decode_single(struct base64_decode_ctx *ctx,
uint8_t *dst,
uint8_t src)
{
- int data;
-
- data = decode_table[src];
+ int data = ctx->alphabet[src];
switch(data)
{
diff --git a/base64-encode.c b/base64-encode.c
index 313c512..d249607 100644
--- a/base64-encode.c
+++ b/base64-encode.c
@@ -38,16 +38,26 @@
#include "base64.h"
-static const uint8_t encode_table[64] =
+static void _base64_encode_raw(struct base64_encode_ctx *ctx, uint8_t *dst,
size_t length, const uint8_t *src);
+
+static const uint8_t default_encode_table[64] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
-#define ENCODE(x) (encode_table[0x3F & (x)])
+#define ENCODE(X) (ctx->alphabet[0x3F & (X)])
void
base64_encode_raw(uint8_t *dst, size_t length, const uint8_t *src)
{
+ struct base64_encode_ctx ctx;
+ base64_encode_init(&ctx);
+ _base64_encode_raw(&ctx, dst, length, src);
+}
+
+void
+_base64_encode_raw(struct base64_encode_ctx *ctx, uint8_t *dst, size_t length,
const uint8_t *src)
+{
const uint8_t *in = src + length;
uint8_t *out = dst + BASE64_ENCODE_RAW_LENGTH(length);
@@ -87,53 +97,13 @@ base64_encode_raw(uint8_t *dst, size_t length, const
uint8_t *src)
assert(out == dst);
}
-#if 0
-unsigned
-base64_encode(uint8_t *dst,
- unsigned src_length,
- const uint8_t *src)
-{
- unsigned dst_length = BASE64_ENCODE_RAW_LENGTH(src_length);
- unsigned n = src_length / 3;
- unsigned left_over = src_length % 3;
- unsigned done = 0;
-
- if (left_over)
- {
- const uint8_t *in = src + n * 3;
- uint8_t *out = dst + dst_length;
-
- switch(left_over)
- {
- case 1:
- *--out = '=';
- *--out = ENCODE(in[0] << 4);
- break;
-
- case 2:
- *--out = ENCODE( in[1] << 2);
- *--out = ENCODE((in[0] << 4) | (in[1] >> 4));
- break;
-
- default:
- abort();
- }
- *--out = ENCODE(in[0] >> 2);
-
- done = 4;
- }
- base64_encode_raw(n, dst, src);
- done += n * 4;
-
- assert(done == dst_length);
-
- return done;
-}
-#endif
-
void
base64_encode_group(uint8_t *dst, uint32_t group)
{
+ struct base64_encode_ctx ctxBase;
+ struct base64_encode_ctx *ctx = &ctxBase;
+ base64_encode_init(ctx);
+
*dst++ = ENCODE(group >> 18);
*dst++ = ENCODE(group >> 12);
*dst++ = ENCODE(group >> 6);
@@ -144,6 +114,7 @@ void
base64_encode_init(struct base64_encode_ctx *ctx)
{
ctx->word = ctx->bits = 0;
+ ctx->alphabet = default_encode_table;
}
/* Encodes a single byte. */
@@ -196,7 +167,7 @@ base64_encode_update(struct base64_encode_ctx *ctx,
{
assert(!(bulk % 3));
- base64_encode_raw(dst + done, bulk, src);
+ _base64_encode_raw(ctx, dst + done, bulk, src);
done += BASE64_ENCODE_RAW_LENGTH(bulk);
src += bulk;
left = left_over;
diff --git a/base64.h b/base64.h
index a6fb823..21381d2 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
@@ -73,11 +75,17 @@ struct base64_encode_ctx
{
unsigned word; /* Leftover bits */
unsigned bits; /* Number of bits, always 0, 2, or 4. */
+ const uint8_t *alphabet; /* which alphabet to use for encoding */
};
+/* initialize encoding context for base-64 */
void
base64_encode_init(struct base64_encode_ctx *ctx);
+/* initialize encoding context for base-64 with URL safe extended alphabet */
+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,
@@ -123,11 +131,17 @@ struct base64_decode_ctx
/* Number of padding characters encountered */
unsigned padding;
+ const signed char *alphabet; /* which alphabet to use for encoding */
};
+/* initialize encoding context for base-64 */
void
base64_decode_init(struct base64_decode_ctx *ctx);
+/* initialize encoding context for base-64 with URL safe extended alphabet */
+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
index e69de29..5b1a802 100644
--- a/base64url-decode.c
+++ b/base64url-decode.c
@@ -0,0 +1,65 @@
+/* base64url-decode.c
+
+ Copyright (C) 2015 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"
+
+static const signed char
+urlextended_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,
+};
+
+void
+base64url_decode_init(struct base64_decode_ctx *ctx)
+{
+ ctx->word = ctx->bits = ctx->padding = 0;
+ ctx->alphabet = urlextended_decode_table;
+}
diff --git a/base64url-encode.c b/base64url-encode.c
index e69de29..1f1eab7 100644
--- a/base64url-encode.c
+++ b/base64url-encode.c
@@ -0,0 +1,48 @@
+/* base64url-encode.c
+
+ Copyright (C) 2015 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"
+
+static const uint8_t urlextended_encode_table[64] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "abcdefghijklmnopqrstuvwxyz"
+ "0123456789-_";
+
+void
+base64url_encode_init(struct base64_encode_ctx *ctx)
+{
+ ctx->word = ctx->bits = 0;
+ ctx->alphabet = urlextended_encode_table;
+}
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