[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

Whitespace in the input is ignored.
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 (isspace(x)) continue;

  if (x > 127 || (x = dec64table[x]) == 255) return -1;

  while (isspace(y = *code++)) ;
  if (y == 0 || (y = dec64table[y]) == 255)
    return -1;

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

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

    while (isspace(y = *code++)) ;
    if (y == '=')
      {
      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
69a70afa	137	Whitespace in the input is ignored.
f4d091fb JH	138	A zero is added on to the end to make it easy in cases where the result is to
	139	be interpreted as text. This is not included in the count. */
	140
	141	static uschar dec64table[] = {
	142	255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, /* 0-15 */
	143	255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, /* 16-31 */
	144	255,255,255,255,255,255,255,255,255,255,255, 62,255,255,255, 63, /* 32-47 */
	145	52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255,255,255,255, /* 48-63 */
	146	255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 64-79 */
	147	15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,255,255,255,255,255, /* 80-95 */
	148	255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 96-111 */
	149	41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,255,255,255,255,255 /* 112-127*/
	150	};
	151
	152	int
	153	b64decode(uschar code, uschar *ptr)
	154	{
	155	int x, y;
	156	uschar result = store_get(3(Ustrlen(code)/4) + 1);
	157
	158	*ptr = result;
	159
	160	/* Each cycle of the loop handles a quantum of 4 input bytes. For the last
	161	quantum this may decode to 1, 2, or 3 output bytes. */
	162
	163	while ((x = *code++) != 0)
	164	{
69a70afa JH	165	if (isspace(x)) continue;
69a70afa JH	166
f4d091fb	167	if (x > 127 \|\| (x = dec64table[x]) == 255) return -1;
69a70afa JH	168
	169	while (isspace(y = *code++)) ;
	170	if (y == 0 \|\| (y = dec64table[y]) == 255)
f4d091fb JH	171	return -1;
	172
	173	*result++ = (x << 2) \| (y >> 4);
	174
69a70afa JH	175	while (isspace(x = *code++)) ;
69a70afa JH	176	if (x == '=')
f4d091fb	177	{
69a70afa JH	178	while (isspace(x = *code++)) ;
69a70afa JH	179	if (x != '=' \|\| *code != 0) return -1;
f4d091fb JH	180	}
	181	else
	182	{
	183	if (x > 127 \|\| (x = dec64table[x]) == 255) return -1;
	184	*result++ = (y << 4) \| (x >> 2);
69a70afa JH	185
	186	while (isspace(y = *code++)) ;
	187	if (y == '=')
f4d091fb JH	188	{
	189	if (*code != 0) return -1;
	190	}
	191	else
	192	{
	193	if (y > 127 \|\| (y = dec64table[y]) == 255) return -1;
	194	*result++ = (x << 6) \| y;
	195	}
	196	}
	197	}
	198
	199	*result = 0;
	200	return result - *ptr;
	201	}
	202
	203
	204	/*************************************************
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	206	/*************************************************
	207	/*************************************************
	208	/*************************************************
	209	/*************************************************
	210	/*************************************************
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	212	/*************************************************
	213	/*************************************************
	214	/*************************************************
	215	/*************************************************
	216	/*************************************************
	217	/*************************************************
	218	/*************************************************
	219	/*************************************************
	220
	221	/*************************************************
	222	* Encode byte-string in base 64 *
	223	*************************************************/
	224
	225	/* This function encodes a string of bytes, containing any values whatsoever,
	226	in base 64 as defined in RFC 2045 (MIME) and required by the SMTP AUTH
	227	extension (RFC 2554). The encoding algorithm is written out in a
	228	straightforward way. Turning it into some kind of compact loop is messy and
	229	would probably run more slowly.
	230
	231	Arguments:
	232	clear points to the clear text bytes
	233	len the number of bytes to encode
	234
	235	Returns: a pointer to the zero-terminated base 64 string, which
	236	is in working store
	237	*/
	238
	239	static uschar *enc64table =
	240	US"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
	241
	242	uschar *
	243	b64encode(uschar *clear, int len)
	244	{
	245	uschar code = store_get(4((len+2)/3) + 1);
	246	uschar *p = code;
	247
	248	while (len-- >0)
	249	{
	250	register int x, y;
	251
252	x = *clear++;
253	*p++ = enc64table[(x >> 2) & 63];
254
255	if (len-- <= 0)
256	{
257	*p++ = enc64table[(x << 4) & 63];
258	*p++ = '=';
259	*p++ = '=';
260	break;
261	}
262
263	y = *clear++;
264	*p++ = enc64table[((x << 4) \| ((y >> 4) & 15)) & 63];
265
266	if (len-- <= 0)
267	{
268	*p++ = enc64table[(y << 2) & 63];
269	*p++ = '=';
270	break;
271	}
272
273	x = *clear++;
274	*p++ = enc64table[((y << 2) \| ((x >> 6) & 3)) & 63];
275
276	*p++ = enc64table[x & 63];
277	}
278
279	*p = 0;
280
281	return code;
282	}
283
284
285	/* End of base64.c */
286	/* vi: sw ai sw=2
287	*/