[exim.git] / src / src / base64.c

/*************************************************
*     Exim - an Internet mail transport agent    *
*************************************************/

/* Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004, 2015 */
/* License: GPL */

/* Copyright (c) University of Cambridge 1995 - 2015 */
/* See the file NOTICE for conditions of use and distribution. */


#include "exim.h"
#ifdef WITH_CONTENT_SCAN	/* file-IO specific decode function */
# include "mime.h"

/* BASE64 decoder matrix */
static unsigned char mime_b64[256]={
/*   0 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/*  16 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/*  32 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,   62,  128,  128,  128,   63,
/*  48 */   52,   53,   54,   55,   56,   57,   58,   59,   60,   61,  128,  128,  128,  255,  128,  128,
/*  64 */  128,    0,    1,    2,    3,    4,    5,    6,    7,    8,    9,   10,   11,   12,   13,   14,
/*  80 */   15,   16,   17,   18,   19,   20,   21,   22,   23,   24,   25,  128,  128,  128,  128,  128,
/*  96 */  128,   26,   27,   28,   29,   30,   31,   32,   33,   34,   35,   36,   37,   38,   39,   40,
/* 112 */   41,   42,   43,   44,   45,   46,   47,   48,   49,   50,   51,  128,  128,  128,  128,  128,
/* 128 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/* 144 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/* 160 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/* 176 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/* 192 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/* 208 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/* 224 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,
/* 240 */  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128,  128
};

/* decode base64 MIME part */
ssize_t
mime_decode_base64(FILE * in, FILE * out, uschar * boundary)
{
uschar ibuf[MIME_MAX_LINE_LENGTH], obuf[MIME_MAX_LINE_LENGTH];
uschar *ipos, *opos;
ssize_t len, size = 0;
int bytestate = 0;

opos = obuf;

while (Ufgets(ibuf, MIME_MAX_LINE_LENGTH, in) != NULL)
  {
  if (boundary != NULL
     && Ustrncmp(ibuf, "--", 2) == 0
     && Ustrncmp((ibuf+2), boundary, Ustrlen(boundary)) == 0
     )
    break;

  for (ipos = ibuf ; *ipos != '\r' && *ipos != '\n' && *ipos != 0; ++ipos)
    if (*ipos == '=')			/* skip padding */
      ++bytestate;

    else if (mime_b64[*ipos] == 128)	/* skip bad characters */
      mime_set_anomaly(MIME_ANOMALY_BROKEN_BASE64);

    /* simple state-machine */
    else switch((bytestate++) & 3)
      {
      case 0:
	*opos = mime_b64[*ipos] << 2; break;
      case 1:
	*opos++ |= mime_b64[*ipos] >> 4;
	*opos = mime_b64[*ipos] << 4; break;
      case 2:
	*opos++ |= mime_b64[*ipos] >> 2;
	*opos = mime_b64[*ipos] << 6; break;
      case 3:
	*opos++ |= mime_b64[*ipos]; break;
      }

  /* something to write? */
  len = opos - obuf;
  if (len > 0)
    {
    if (fwrite(obuf, 1, len, out) != len) return -1; /* error */
    size += len;
    /* copy incomplete last byte to start of obuf, where we continue */
    if ((bytestate & 3) != 0)
      *obuf = *opos;
    opos = obuf;
    }
  } /* while */

/* write out last byte if it was incomplete */
if (bytestate & 3)
  {
  if (fwrite(obuf, 1, 1, out) != 1) return -1;
  ++size;
  }

return size;
}

#endif	/*WITH_CONTENT_SCAN*/

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/*************************************************
*          Decode byte-string in base 64         *
*************************************************/

/* This function decodes a string in base 64 format as defined in RFC 2045
(MIME) and required by the SMTP AUTH extension (RFC 2554). The decoding
algorithm is written out in a straightforward way. Turning it into some kind of
compact loop is messy and would probably run more slowly.

Arguments:
  code        points to the coded string, zero-terminated
  ptr         where to put the pointer to the result, which is in
              dynamic store, and zero-terminated

Returns:      the number of bytes in the result,
              or -1 if the input was malformed

A zero is added on to the end to make it easy in cases where the result is to
be interpreted as text. This is not included in the count. */

static uschar dec64table[] = {
  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, /*  0-15 */
  255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, /* 16-31 */
  255,255,255,255,255,255,255,255,255,255,255, 62,255,255,255, 63, /* 32-47 */
   52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255,255,255,255, /* 48-63 */
  255,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, /* 64-79 */
   15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,255,255,255,255,255, /* 80-95 */
  255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 96-111 */
   41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,255,255,255,255,255  /* 112-127*/
};

int
b64decode(uschar *code, uschar **ptr)
{
int x, y;
uschar *result = store_get(3*(Ustrlen(code)/4) + 1);

*ptr = result;

/* Each cycle of the loop handles a quantum of 4 input bytes. For the last
quantum this may decode to 1, 2, or 3 output bytes. */

while ((x = *code++) != 0)
  {
  if (x > 127 || (x = dec64table[x]) == 255) return -1;
  if ((y = *code++) == 0 || (y = dec64table[y]) == 255)
    return -1;

  *result++ = (x << 2) | (y >> 4);

  if ((x = *code++) == '=')
    {
    if (*code++ != '=' || *code != 0) return -1;
    }
  else
    {
    if (x > 127 || (x = dec64table[x]) == 255) return -1;
    *result++ = (y << 4) | (x >> 2);
    if ((y = (*code++)) == '=')
      {
      if (*code != 0) return -1;
      }
    else
      {
      if (y > 127 || (y = dec64table[y]) == 255) return -1;
      *result++ = (x << 6) | y;
      }
    }
  }

*result = 0;
return result - *ptr;
}


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/*************************************************
*          Encode byte-string in base 64         *
*************************************************/

/* This function encodes a string of bytes, containing any values whatsoever,
in base 64 as defined in RFC 2045 (MIME) and required by the SMTP AUTH
extension (RFC 2554). The encoding algorithm is written out in a
straightforward way. Turning it into some kind of compact loop is messy and
would probably run more slowly.

Arguments:
  clear       points to the clear text bytes
  len         the number of bytes to encode

Returns:      a pointer to the zero-terminated base 64 string, which
              is in working store
*/

static uschar *enc64table =
  US"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

uschar *
b64encode(uschar *clear, int len)
{
uschar *code = store_get(4*((len+2)/3) + 1);
uschar *p = code;

while (len-- >0)
  {
  register int x, y;

  x = *clear++;
  *p++ = enc64table[(x >> 2) & 63];

  if (len-- <= 0)
    {
    *p++ = enc64table[(x << 4) & 63];
    *p++ = '=';
    *p++ = '=';
    break;
    }

  y = *clear++;
  *p++ = enc64table[((x << 4) | ((y >> 4) & 15)) & 63];

  if (len-- <= 0)
    {
    *p++ = enc64table[(y << 2) & 63];
    *p++ = '=';
    break;
    }

  x = *clear++;
  *p++ = enc64table[((y << 2) | ((x >> 6) & 3)) & 63];

  *p++ = enc64table[x & 63];
  }

*p = 0;

return code;
}


/* End of base64.c */
/* vi: sw ai sw=2
*/
Commit	Line	Data
f4d091fb JH	1	/*************************************************
	2	* Exim - an Internet mail transport agent *
	3	*************************************************/
	4
	5	/* Copyright (c) Tom Kistner <tom@duncanthrax.net> 2004, 2015 */
	6	/* License: GPL */
	7
	8	/* Copyright (c) University of Cambridge 1995 - 2015 */
	9	/* See the file NOTICE for conditions of use and distribution. */
	10
	11
	12	#include "exim.h"
	13	#ifdef WITH_CONTENT_SCAN /* file-IO specific decode function */
	14	# include "mime.h"
	15
	16	/* BASE64 decoder matrix */
	17	static unsigned char mime_b64[256]={
	18	/* 0 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	19	/* 16 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	20	/* 32 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 62, 128, 128, 128, 63,
	21	/* 48 */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 128, 128, 128, 255, 128, 128,
	22	/* 64 */ 128, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
	23	/* 80 */ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 128, 128, 128, 128, 128,
	24	/* 96 */ 128, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
	25	/* 112 */ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 128, 128, 128, 128, 128,
	26	/* 128 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	27	/* 144 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	28	/* 160 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	29	/* 176 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	30	/* 192 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	31	/* 208 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	32	/* 224 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
	33	/* 240 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128
	34	};
	35
	36	/* decode base64 MIME part */
	37	ssize_t
	38	mime_decode_base64(FILE * in, FILE * out, uschar * boundary)
	39	{
	40	uschar ibuf[MIME_MAX_LINE_LENGTH], obuf[MIME_MAX_LINE_LENGTH];
	41	uschar ipos, opos;
	42	ssize_t len, size = 0;
	43	int bytestate = 0;
	44
	45	opos = obuf;
	46
	47	while (Ufgets(ibuf, MIME_MAX_LINE_LENGTH, in) != NULL)
	48	{
	49	if (boundary != NULL
	50	&& Ustrncmp(ibuf, "--", 2) == 0
	51	&& Ustrncmp((ibuf+2), boundary, Ustrlen(boundary)) == 0
	52	)
	53	break;
	54
	55	for (ipos = ibuf ; ipos != '\r' && ipos != '\n' && *ipos != 0; ++ipos)
	56	if (ipos == '=') / skip padding */
	57	++bytestate;
	58
	59	else if (mime_b64[ipos] == 128) / skip bad characters */
	60	mime_set_anomaly(MIME_ANOMALY_BROKEN_BASE64);
	61
	62	/* simple state-machine */
	63	else switch((bytestate++) & 3)
	64	{
65	case 0:
66	opos = mime_b64[ipos] << 2; break;
67	case 1:
68	opos++ \|= mime_b64[ipos] >> 4;
69	opos = mime_b64[ipos] << 4; break;
70	case 2:
71	opos++ \|= mime_b64[ipos] >> 2;
72	opos = mime_b64[ipos] << 6; break;
73	case 3:
74	opos++ \|= mime_b64[ipos]; break;
75	}
76
77	/* something to write? */
78	len = opos - obuf;
79	if (len > 0)
80	{
81	if (fwrite(obuf, 1, len, out) != len) return -1; /* error */
82	size += len;
83	/* copy incomplete last byte to start of obuf, where we continue */
84	if ((bytestate & 3) != 0)
85	obuf = opos;
86	opos = obuf;
87	}
88	} /* while */
89
90	/* write out last byte if it was incomplete */
91	if (bytestate & 3)
92	{
93	if (fwrite(obuf, 1, 1, out) != 1) return -1;
94	++size;
95	}
96
97	return size;
98	}
99
100	#endif /WITH_CONTENT_SCAN/
101
102	/*************************************************
103	/*************************************************
104	/*************************************************
105	/*************************************************
106	/*************************************************
107	/*************************************************
108	/*************************************************
109	/*************************************************
110	/*************************************************
111	/*************************************************
112	/*************************************************
113	/*************************************************
114	/*************************************************
115	/*************************************************
116	/*************************************************
117	/*************************************************
118
119
120	/*************************************************
121	* Decode byte-string in base 64 *
122	*************************************************/
123
124	/* This function decodes a string in base 64 format as defined in RFC 2045
125	(MIME) and required by the SMTP AUTH extension (RFC 2554). The decoding
126	algorithm is written out in a straightforward way. Turning it into some kind of
127	compact loop is messy and would probably run more slowly.
128
129	Arguments:
130	code points to the coded string, zero-terminated
131	ptr where to put the pointer to the result, which is in
132	dynamic store, and zero-terminated
133
134	Returns: the number of bytes in the result,
135	or -1 if the input was malformed
136
137	A zero is added on to the end to make it easy in cases where the result is to
138	be interpreted as text. This is not included in the count. */
139
140	static uschar dec64table[] = {
141	255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, /* 0-15 */
142	255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, /* 16-31 */
143	255,255,255,255,255,255,255,255,255,255,255, 62,255,255,255, 63, /* 32-47 */
144	52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255,255,255,255, /* 48-63 */
145	255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 64-79 */
146	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,255,255,255,255,255, /* 80-95 */
147	255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 96-111 */
148	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,255,255,255,255,255 /* 112-127*/
149	};
150
151	int
152	b64decode(uschar code, uschar *ptr)
153	{
154	int x, y;
155	uschar result = store_get(3(Ustrlen(code)/4) + 1);
156
157	*ptr = result;
158
159	/* Each cycle of the loop handles a quantum of 4 input bytes. For the last
160	quantum this may decode to 1, 2, or 3 output bytes. */
161
162	while ((x = *code++) != 0)
163	{
164	if (x > 127 \|\| (x = dec64table[x]) == 255) return -1;
165	if ((y = *code++) == 0 \|\| (y = dec64table[y]) == 255)
166	return -1;
167
168	*result++ = (x << 2) \| (y >> 4);
169
170	if ((x = *code++) == '=')
171	{
172	if (code++ != '=' \|\| code != 0) return -1;
173	}
174	else
175	{
176	if (x > 127 \|\| (x = dec64table[x]) == 255) return -1;
177	*result++ = (y << 4) \| (x >> 2);
178	if ((y = (*code++)) == '=')
179	{
180	if (*code != 0) return -1;
181	}
182	else
183	{
184	if (y > 127 \|\| (y = dec64table[y]) == 255) return -1;
185	*result++ = (x << 6) \| y;
186	}
187	}
188	}
189
190	*result = 0;
191	return result - *ptr;
192	}
193
194
195	/*************************************************
196	/*************************************************
197	/*************************************************
198	/*************************************************
199	/*************************************************
200	/*************************************************
201	/*************************************************
202	/*************************************************
203	/*************************************************
204	/*************************************************
205	/*************************************************
206	/*************************************************
207	/*************************************************
208	/*************************************************
209	/*************************************************
210	/*************************************************
211
212	/*************************************************
213	* Encode byte-string in base 64 *
214	*************************************************/
215
216	/* This function encodes a string of bytes, containing any values whatsoever,
217	in base 64 as defined in RFC 2045 (MIME) and required by the SMTP AUTH
218	extension (RFC 2554). The encoding algorithm is written out in a
219	straightforward way. Turning it into some kind of compact loop is messy and
220	would probably run more slowly.
221
222	Arguments:
223	clear points to the clear text bytes
224	len the number of bytes to encode
225
226	Returns: a pointer to the zero-terminated base 64 string, which
227	is in working store
228	*/
229
230	static uschar *enc64table =
231	US"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
232
233	uschar *
234	b64encode(uschar *clear, int len)
235	{
236	uschar code = store_get(4((len+2)/3) + 1);
237	uschar *p = code;
238
239	while (len-- >0)
240	{
241	register int x, y;
242
243	x = *clear++;
244	*p++ = enc64table[(x >> 2) & 63];
245
246	if (len-- <= 0)
247	{
248	*p++ = enc64table[(x << 4) & 63];
249	*p++ = '=';
250	*p++ = '=';
251	break;
252	}
253
254	y = *clear++;
255	*p++ = enc64table[((x << 4) \| ((y >> 4) & 15)) & 63];
256
257	if (len-- <= 0)
258	{
259	*p++ = enc64table[(y << 2) & 63];
260	*p++ = '=';
261	break;
262	}
263
264	x = *clear++;
265	*p++ = enc64table[((y << 2) \| ((x >> 6) & 3)) & 63];
266
267	*p++ = enc64table[x & 63];
268	}
269
270	*p = 0;
271
272	return code;
273	}
274
275
276	/* End of base64.c */
277	/* vi: sw ai sw=2
278	*/