iPXE
base64.c
Go to the documentation of this file.
1 /*
2  * Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation; either version 2 of the
7  * License, or any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 #include <stdint.h>
27 #include <string.h>
28 #include <ctype.h>
29 #include <errno.h>
30 #include <assert.h>
31 #include <ipxe/base64.h>
32 
33 /** @file
34  *
35  * Base64 encoding
36  *
37  */
38 
39 static const char base64[64] =
40  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
41 
42 /**
43  * Base64-encode data
44  *
45  * @v raw Raw data
46  * @v raw_len Length of raw data
47  * @v data Buffer
48  * @v len Length of buffer
49  * @ret len Encoded length
50  */
51 size_t base64_encode ( const void *raw, size_t raw_len, char *data,
52  size_t len ) {
53  const uint8_t *raw_bytes = ( ( const uint8_t * ) raw );
54  size_t raw_bit_len = ( 8 * raw_len );
55  size_t used = 0;
56  unsigned int bit;
57  unsigned int byte;
58  unsigned int shift;
59  unsigned int tmp;
60 
61  for ( bit = 0 ; bit < raw_bit_len ; bit += 6, used++ ) {
62  byte = ( bit / 8 );
63  shift = ( bit % 8 );
64  tmp = ( raw_bytes[byte] << shift );
65  if ( ( byte + 1 ) < raw_len )
66  tmp |= ( raw_bytes[ byte + 1 ] >> ( 8 - shift ) );
67  tmp = ( ( tmp >> 2 ) & 0x3f );
68  if ( used < len )
69  data[used] = base64[tmp];
70  }
71  for ( ; ( bit % 8 ) != 0 ; bit += 6, used++ ) {
72  if ( used < len )
73  data[used] = '=';
74  }
75  if ( used < len )
76  data[used] = '\0';
77  if ( len )
78  data[ len - 1 ] = '\0'; /* Ensure terminator exists */
79 
80  return used;
81 }
82 
83 /**
84  * Base64-decode string
85  *
86  * @v encoded Encoded string
87  * @v data Buffer
88  * @v len Length of buffer
89  * @ret len Length of data, or negative error
90  */
91 int base64_decode ( const char *encoded, void *data, size_t len ) {
92  const char *in = encoded;
93  uint8_t *out = data;
94  uint8_t in_char;
95  char *match;
96  int in_bits;
97  unsigned int bit = 0;
98  unsigned int pad_count = 0;
99  size_t offset;
100 
101  /* Zero the output buffer */
102  memset ( data, 0, len );
103 
104  /* Decode string */
105  while ( ( in_char = *(in++) ) ) {
106 
107  /* Ignore whitespace characters */
108  if ( isspace ( in_char ) )
109  continue;
110 
111  /* Process pad characters */
112  if ( in_char == '=' ) {
113  if ( pad_count >= 2 ) {
114  DBG ( "Base64-encoded string \"%s\" has too "
115  "many pad characters\n", encoded );
116  return -EINVAL;
117  }
118  pad_count++;
119  bit -= 2; /* unused_bits = ( 2 * pad_count ) */
120  continue;
121  }
122  if ( pad_count ) {
123  DBG ( "Base64-encoded string \"%s\" has invalid pad "
124  "sequence\n", encoded );
125  return -EINVAL;
126  }
127 
128  /* Process normal characters */
129  match = strchr ( base64, in_char );
130  if ( ! match ) {
131  DBG ( "Base64-encoded string \"%s\" contains invalid "
132  "character '%c'\n", encoded, in_char );
133  return -EINVAL;
134  }
135  in_bits = ( match - base64 );
136 
137  /* Add to raw data */
138  in_bits <<= 2;
139  offset = ( bit / 8 );
140  if ( offset < len )
141  out[offset] |= ( in_bits >> ( bit % 8 ) );
142  offset++;
143  if ( offset < len )
144  out[offset] |= ( in_bits << ( 8 - ( bit % 8 ) ) );
145  bit += 6;
146  }
147 
148  /* Check that we decoded a whole number of bytes */
149  if ( ( bit % 8 ) != 0 ) {
150  DBG ( "Base64-encoded string \"%s\" has invalid bit length "
151  "%d\n", encoded, bit );
152  return -EINVAL;
153  }
154 
155  /* Return length in bytes */
156  return ( bit / 8 );
157 }
#define EINVAL
Invalid argument.
Definition: errno.h:428
__be32 in[4]
Definition: CIB_PRM.h:35
static unsigned int unsigned int bit
Definition: bigint.h:205
Error codes.
int base64_decode(const char *encoded, void *data, size_t len)
Base64-decode string.
Definition: base64.c:91
Character types.
Assertions.
static userptr_t size_t offset
Offset of the first segment within the content.
Definition: deflate.h:259
__be32 out[4]
Definition: CIB_PRM.h:36
static size_t raw_len
Definition: base16.h:50
char * strchr(const char *src, int character)
Find character within a string.
Definition: string.c:241
uint8_t * tmp
Definition: entropy.h:156
int isspace(int character)
Check to see if character is a space.
Definition: ctype.c:41
unsigned char uint8_t
Definition: stdint.h:10
unsigned char byte
Definition: smc9000.h:38
Base64 encoding.
uint32_t len
Length.
Definition: ena.h:14
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
__be32 raw[7]
Definition: CIB_PRM.h:28
struct arbelprm_port_state_change_st data
Message.
Definition: arbel.h:12
#define DBG(...)
Print a debugging message.
Definition: compiler.h:498
String functions.
static const char base64[64]
Definition: base64.c:39
size_t base64_encode(const void *raw, size_t raw_len, char *data, size_t len)
Base64-encode data.
Definition: base64.c:51
void * memset(void *dest, int character, size_t len) __nonnull