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Add base64url encoding/decoding per RFC 4648

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This adds functionality needed for parsing and generating JSON Web Key
data structures in DPP.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
This commit is contained in:
Jouni Malinen 2017-06-15 21:17:54 +03:00 committed by Jouni Malinen
parent 77f273c82c
commit 0ffdc8b196
2 changed files with 95 additions and 48 deletions
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139
src/utils/base64.c
View file

@ -13,21 +13,14 @@
static const unsigned char base64_table[65] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const unsigned char base64_url_table[65] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
/**
* base64_encode - Base64 encode
* @src: Data to be encoded
* @len: Length of the data to be encoded
* @out_len: Pointer to output length variable, or %NULL if not used
* Returns: Allocated buffer of out_len bytes of encoded data,
* or %NULL on failure
*
* Caller is responsible for freeing the returned buffer. Returned buffer is
* nul terminated to make it easier to use as a C string. The nul terminator is
* not included in out_len.
*/
unsigned char * base64_encode(const unsigned char *src, size_t len,
size_t *out_len)
static unsigned char * base64_gen_encode(const unsigned char *src, size_t len,
size_t *out_len,
const unsigned char *table,
int add_pad)
{
unsigned char *out, *pos;
const unsigned char *end, *in;
@ -35,7 +28,8 @@ unsigned char * base64_encode(const unsigned char *src, size_t len,
int line_len;
olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
olen += olen / 72; /* line feeds */
if (add_pad)
olen += olen / 72; /* line feeds */
olen++; /* nul termination */
if (olen < len)
return NULL; /* integer overflow */
@ -48,35 +42,35 @@ unsigned char * base64_encode(const unsigned char *src, size_t len,
pos = out;
line_len = 0;
while (end - in >= 3) {
*pos++ = base64_table[(in[0] >> 2) & 0x3f];
*pos++ = base64_table[(((in[0] & 0x03) << 4) |
(in[1] >> 4)) & 0x3f];
*pos++ = base64_table[(((in[1] & 0x0f) << 2) |
(in[2] >> 6)) & 0x3f];
*pos++ = base64_table[in[2] & 0x3f];
*pos++ = table[(in[0] >> 2) & 0x3f];
*pos++ = table[(((in[0] & 0x03) << 4) | (in[1] >> 4)) & 0x3f];
*pos++ = table[(((in[1] & 0x0f) << 2) | (in[2] >> 6)) & 0x3f];
*pos++ = table[in[2] & 0x3f];
in += 3;
line_len += 4;
if (line_len >= 72) {
if (add_pad && line_len >= 72) {
*pos++ = '\n';
line_len = 0;
}
}
if (end - in) {
*pos++ = base64_table[(in[0] >> 2) & 0x3f];
*pos++ = table[(in[0] >> 2) & 0x3f];
if (end - in == 1) {
*pos++ = base64_table[((in[0] & 0x03) << 4) & 0x3f];
*pos++ = '=';
*pos++ = table[((in[0] & 0x03) << 4) & 0x3f];
if (add_pad)
*pos++ = '=';
} else {
*pos++ = base64_table[(((in[0] & 0x03) << 4) |
(in[1] >> 4)) & 0x3f];
*pos++ = base64_table[((in[1] & 0x0f) << 2) & 0x3f];
*pos++ = table[(((in[0] & 0x03) << 4) |
(in[1] >> 4)) & 0x3f];
*pos++ = table[((in[1] & 0x0f) << 2) & 0x3f];
}
*pos++ = '=';
if (add_pad)
*pos++ = '=';
line_len += 4;
}
if (line_len)
if (add_pad && line_len)
*pos++ = '\n';
*pos = '\0';
@ -86,26 +80,18 @@ unsigned char * base64_encode(const unsigned char *src, size_t len,
}
/**
* base64_decode - Base64 decode
* @src: Data to be decoded
* @len: Length of the data to be decoded
* @out_len: Pointer to output length variable
* Returns: Allocated buffer of out_len bytes of decoded data,
* or %NULL on failure
*
* Caller is responsible for freeing the returned buffer.
*/
unsigned char * base64_decode(const unsigned char *src, size_t len,
size_t *out_len)
static unsigned char * base64_gen_decode(const unsigned char *src, size_t len,
size_t *out_len,
const unsigned char *table)
{
unsigned char dtable[256], *out, *pos, block[4], tmp;
size_t i, count, olen;
int pad = 0;
size_t extra_pad;
os_memset(dtable, 0x80, 256);
for (i = 0; i < sizeof(base64_table) - 1; i++)
dtable[base64_table[i]] = (unsigned char) i;
dtable[table[i]] = (unsigned char) i;
dtable['='] = 0;
count = 0;
@ -114,21 +100,28 @@ unsigned char * base64_decode(const unsigned char *src, size_t len,
count++;
}
if (count == 0 || count % 4)
if (count == 0)
return NULL;
extra_pad = (4 - count % 4) % 4;
olen = count / 4 * 3;
olen = (count + extra_pad) / 4 * 3;
pos = out = os_malloc(olen);
if (out == NULL)
return NULL;
count = 0;
for (i = 0; i < len; i++) {
tmp = dtable[src[i]];
for (i = 0; i < len + extra_pad; i++) {
unsigned char val;
if (i >= len)
val = '=';
else
val = src[i];
tmp = dtable[val];
if (tmp == 0x80)
continue;
if (src[i] == '=')
if (val == '=')
pad++;
block[count] = tmp;
count++;
@ -155,3 +148,53 @@ unsigned char * base64_decode(const unsigned char *src, size_t len,
*out_len = pos - out;
return out;
}
/**
* base64_encode - Base64 encode
* @src: Data to be encoded
* @len: Length of the data to be encoded
* @out_len: Pointer to output length variable, or %NULL if not used
* Returns: Allocated buffer of out_len bytes of encoded data,
* or %NULL on failure
*
* Caller is responsible for freeing the returned buffer. Returned buffer is
* nul terminated to make it easier to use as a C string. The nul terminator is
* not included in out_len.
*/
unsigned char * base64_encode(const unsigned char *src, size_t len,
size_t *out_len)
{
return base64_gen_encode(src, len, out_len, base64_table, 0);
}
unsigned char * base64_url_encode(const unsigned char *src, size_t len,
size_t *out_len, int add_pad)
{
return base64_gen_encode(src, len, out_len, base64_url_table, add_pad);
}
/**
* base64_decode - Base64 decode
* @src: Data to be decoded
* @len: Length of the data to be decoded
* @out_len: Pointer to output length variable
* Returns: Allocated buffer of out_len bytes of decoded data,
* or %NULL on failure
*
* Caller is responsible for freeing the returned buffer.
*/
unsigned char * base64_decode(const unsigned char *src, size_t len,
size_t *out_len)
{
return base64_gen_decode(src, len, out_len, base64_table);
}
unsigned char * base64_url_decode(const unsigned char *src, size_t len,
size_t *out_len)
{
return base64_gen_decode(src, len, out_len, base64_url_table);
}

4
src/utils/base64.h
View file

@ -13,5 +13,9 @@ unsigned char * base64_encode(const unsigned char *src, size_t len,
size_t *out_len);
unsigned char * base64_decode(const unsigned char *src, size_t len,
size_t *out_len);
unsigned char * base64_url_encode(const unsigned char *src, size_t len,
size_t *out_len, int add_pad);
unsigned char * base64_url_decode(const unsigned char *src, size_t len,
size_t *out_len);
#endif /* BASE64_H */