[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 - 2016 */
/* 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
              allocated 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(const 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;
  /* debug_printf("b64d: '%c'\n", x); */

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

  while (isspace(y = *code++)) ;
  /* debug_printf("b64d: '%c'\n", y); */
  if (y == 0 || (y = dec64table[y]) == 255)
    return -1;

  *result++ = (x << 2) | (y >> 4);
  /* debug_printf("b64d:      -> %02x\n", result[-1]); */

  while (isspace(x = *code++)) ;
  /* debug_printf("b64d: '%c'\n", x); */
  if (x == '=')		/* endmarker, but there should be another */
    {
    while (isspace(x = *code++)) ;
    /* debug_printf("b64d: '%c'\n", x); */
    if (x != '=') return -1;
    while (isspace(y = *code++)) ;
    if (y != 0) return -1;
    /* debug_printf("b64d: DONE\n"); */
    break;
    }
  else
    {
    if (x > 127 || (x = dec64table[x]) == 255) return -1;
    *result++ = (y << 4) | (x >> 2);
    /* debug_printf("b64d:      -> %02x\n", result[-1]); */

    while (isspace(y = *code++)) ;
    /* debug_printf("b64d: '%c'\n", y); */
    if (y == '=')
      {
      while (isspace(y = *code++)) ;
      if (y != 0) return -1;
      /* debug_printf("b64d: DONE\n"); */
      break;
      }
    else
      {
      if (y > 127 || (y = dec64table[y]) == 255) return -1;
      *result++ = (x << 6) | y;
      /* debug_printf("b64d:      -> %02x\n", result[-1]); */
      }
    }
  }

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


/*************************************************
*          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
80fea873	8	/* Copyright (c) University of Cambridge 1995 - 2016 */
f4d091fb JH	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	/*************************************************
3c51463e JH	103	*************************************************
	104	*************************************************
	105	*************************************************
	106	*************************************************
	107	*************************************************
	108	*************************************************
	109	*************************************************
	110	*************************************************
	111	*************************************************
	112	*************************************************
	113	*************************************************
	114	*************************************************
	115	*************************************************
	116	*************************************************
	117	*************************************************/
f4d091fb JH	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
df3def24	132	allocated store, and zero-terminated
f4d091fb JH	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
35cf75e9	153	b64decode(const uschar code, uschar *ptr)
f4d091fb JH	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	165	if (isspace(x)) continue;
df3def24	166	/* debug_printf("b64d: '%c'\n", x); */
69a70afa	167
f4d091fb	168	if (x > 127 \|\| (x = dec64table[x]) == 255) return -1;
69a70afa JH	169
69a70afa JH	170	while (isspace(y = *code++)) ;
df3def24	171	/* debug_printf("b64d: '%c'\n", y); */
69a70afa	172	if (y == 0 \|\| (y = dec64table[y]) == 255)
f4d091fb JH	173	return -1;
	174
	175	*result++ = (x << 2) \| (y >> 4);
df3def24	176	/* debug_printf("b64d: -> %02x\n", result[-1]); */
f4d091fb	177
69a70afa	178	while (isspace(x = *code++)) ;
df3def24 JH	179	/* debug_printf("b64d: '%c'\n", x); */
df3def24 JH	180	if (x == '=') /* endmarker, but there should be another */
f4d091fb	181	{
69a70afa	182	while (isspace(x = *code++)) ;
df3def24 JH	183	/* debug_printf("b64d: '%c'\n", x); */
	184	if (x != '=') return -1;
	185	while (isspace(y = *code++)) ;
	186	if (y != 0) return -1;
	187	/* debug_printf("b64d: DONE\n"); */
	188	break;
f4d091fb JH	189	}
	190	else
	191	{
	192	if (x > 127 \|\| (x = dec64table[x]) == 255) return -1;
	193	*result++ = (y << 4) \| (x >> 2);
df3def24	194	/* debug_printf("b64d: -> %02x\n", result[-1]); */
69a70afa JH	195
69a70afa JH	196	while (isspace(y = *code++)) ;
df3def24	197	/* debug_printf("b64d: '%c'\n", y); */
69a70afa	198	if (y == '=')
f4d091fb	199	{
df3def24 JH	200	while (isspace(y = *code++)) ;
	201	if (y != 0) return -1;
	202	/* debug_printf("b64d: DONE\n"); */
	203	break;
f4d091fb JH	204	}
	205	else
	206	{
	207	if (y > 127 \|\| (y = dec64table[y]) == 255) return -1;
	208	*result++ = (x << 6) \| y;
df3def24	209	/* debug_printf("b64d: -> %02x\n", result[-1]); */
f4d091fb JH	210	}
	211	}
	212	}
	213
	214	*result = 0;
	215	return result - *ptr;
	216	}
	217
	218
f4d091fb JH	219	/*************************************************
	220	* Encode byte-string in base 64 *
	221	*************************************************/
	222
	223	/* This function encodes a string of bytes, containing any values whatsoever,
	224	in base 64 as defined in RFC 2045 (MIME) and required by the SMTP AUTH
	225	extension (RFC 2554). The encoding algorithm is written out in a
	226	straightforward way. Turning it into some kind of compact loop is messy and
	227	would probably run more slowly.
	228
	229	Arguments:
	230	clear points to the clear text bytes
	231	len the number of bytes to encode
	232
	233	Returns: a pointer to the zero-terminated base 64 string, which
	234	is in working store
	235	*/
	236
	237	static uschar *enc64table =
	238	US"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
	239
	240	uschar *
	241	b64encode(uschar *clear, int len)
	242	{
	243	uschar code = store_get(4((len+2)/3) + 1);
	244	uschar *p = code;
	245
	246	while (len-- >0)
	247	{
	248	register int x, y;
	249
	250	x = *clear++;
	251	*p++ = enc64table[(x >> 2) & 63];
	252
	253	if (len-- <= 0)
	254	{
	255	*p++ = enc64table[(x << 4) & 63];
	256	*p++ = '=';
	257	*p++ = '=';
	258	break;
	259	}
	260
	261	y = *clear++;
	262	*p++ = enc64table[((x << 4) \| ((y >> 4) & 15)) & 63];
	263
	264	if (len-- <= 0)
	265	{
	266	*p++ = enc64table[(y << 2) & 63];
	267	*p++ = '=';
	268	break;
	269	}
	270
	271	x = *clear++;
	272	*p++ = enc64table[((y << 2) \| ((x >> 6) & 3)) & 63];
	273
	274	*p++ = enc64table[x & 63];
	275	}
	276
	277	*p = 0;
	278
	279	return code;
	280	}
	281
	282
283	/* End of base64.c */
284	/* vi: sw ai sw=2
285	*/