X-Git-Url: https://diplodocus.org/git/nmh/blobdiff_plain/522c66eae1a144e0631dfaa61f1632e341ea7ce6..872ef4dde72a88ceb1358849a462f791135b842d:/sbr/base64.c diff --git a/sbr/base64.c b/sbr/base64.c index 80ca86e0..cbd225de 100644 --- a/sbr/base64.c +++ b/sbr/base64.c @@ -1,5 +1,4 @@ -/* - * base64.c -- routines for converting to base64 +/* base64.c -- routines for converting to base64 * * This code is Copyright (c) 2012, by the authors of nmh. See the * COPYRIGHT file in the root directory of the nmh distribution for @@ -11,9 +10,20 @@ #include #include -static char nib2b64[0x40+1] = +static const char nib2b64[0x40+1] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; +/* + * Copy data from one file to another, converting to base64-encoding. + * + * Arguments include: + * + * in - Input filehandle (unencoded data) + * out - Output filename (base64-encoded data) + * crlf - If set, output encoded CRLF for every LF on input. + * + * Returns OK on success, NOTOK otherwise. + */ int writeBase64aux (FILE *in, FILE *out, int crlf) { @@ -113,7 +123,7 @@ writeBase64aux (FILE *in, FILE *out, int crlf) 4 * [length/3] + length/57 + 2 But double the length will certainly be sufficient. */ int -writeBase64 (unsigned char *in, size_t length, unsigned char *out) +writeBase64 (const unsigned char *in, size_t length, unsigned char *out) { unsigned int n = BPERLIN; @@ -121,20 +131,19 @@ writeBase64 (unsigned char *in, size_t length, unsigned char *out) unsigned long bits; unsigned char *bp; unsigned int cc; - for (cc = 0, bp = in; length > 0 && cc < 3; ++cc, ++bp, --length) + for (cc = 0; length > 0 && cc < 3; ++cc, --length) /* empty */ ; - if (cc == 0) { + if (cc == 0) break; - } else { - bits = (in[0] & 0xff) << 16; - if (cc > 1) { - bits |= (in[1] & 0xff) << 8; - if (cc > 2) { - bits |= in[2] & 0xff; - } - } - } + + bits = (in[0] & 0xff) << 16; + if (cc > 1) { + bits |= (in[1] & 0xff) << 8; + if (cc > 2) { + bits |= in[2] & 0xff; + } + } for (bp = out + 4; bp > out; bits >>= 6) *--bp = nib2b64[bits & 0x3f]; @@ -168,26 +177,25 @@ writeBase64 (unsigned char *in, size_t length, unsigned char *out) */ int -writeBase64raw (unsigned char *in, size_t length, unsigned char *out) +writeBase64raw (const unsigned char *in, size_t length, unsigned char *out) { while (1) { unsigned long bits; unsigned char *bp; unsigned int cc; - for (cc = 0, bp = in; length > 0 && cc < 3; ++cc, ++bp, --length) + for (cc = 0; length > 0 && cc < 3; ++cc, --length) /* empty */ ; - if (cc == 0) { + if (cc == 0) break; - } else { - bits = (in[0] & 0xff) << 16; - if (cc > 1) { - bits |= (in[1] & 0xff) << 8; - if (cc > 2) { - bits |= in[2] & 0xff; - } - } - } + + bits = (in[0] & 0xff) << 16; + if (cc > 1) { + bits |= (in[1] & 0xff) << 8; + if (cc > 2) { + bits |= in[2] & 0xff; + } + } for (bp = out + 4; bp > out; bits >>= 6) *--bp = nib2b64[bits & 0x3f]; @@ -209,7 +217,7 @@ writeBase64raw (unsigned char *in, size_t length, unsigned char *out) } -static unsigned char b642nib[0x80] = { +static const unsigned char b642nib[0x80] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, @@ -230,11 +238,17 @@ static unsigned char b642nib[0x80] = { /* * Decode a base64 string. The result, decoded, must be freed by the caller. - * See description of arguments with declaration in h/prototypes.h. + * + * encoded - the string to be decoded + * decoded - the decoded bytes + * len - number of decoded bytes + * skip-crs - non-zero for text content, and for which CR's should be + * skipped + * digest - for an MD5 digest, it can be null */ int -decodeBase64 (const char *encoded, const char **decoded, size_t *len, int skip_crs, - unsigned char *digest) { +decodeBase64 (const char *encoded, unsigned char **decoded, size_t *len, + int skip_crs, unsigned char *digest) { const char *cp = encoded; int self_delimiting = 0; int bitno, skip; @@ -243,7 +257,8 @@ decodeBase64 (const char *encoded, const char **decoded, size_t *len, int skip_c charstring_t decoded_c = charstring_create (strlen (encoded)); MD5_CTX mdContext; - if (digest) { MD5Init (&mdContext); } + if (digest) + MD5Init (&mdContext); bitno = 18; bits = 0L; @@ -259,7 +274,8 @@ decodeBase64 (const char *encoded, const char **decoded, size_t *len, int skip_c } if (skip || (((unsigned char) *cp) & 0x80) || (value = b642nib[((unsigned char) *cp) & 0x7f]) > 0x3f) { - advise (NULL, "invalid BASE64 encoding in %s", encoded); + inform("invalid base64 byte %#x: %.42s", + *(unsigned char *)cp, cp); charstring_free (decoded_c); *decoded = NULL; @@ -274,19 +290,22 @@ test_end: if (! skip_crs || b != '\r') { charstring_push_back (decoded_c, b); } - if (digest) { MD5Update (&mdContext, (unsigned char *) &b, 1); } + if (digest) + MD5Update (&mdContext, (unsigned char *) &b, 1); if (skip < 2) { b = (bits >> 8) & 0xff; if (! skip_crs || b != '\r') { charstring_push_back (decoded_c, b); } - if (digest) { MD5Update (&mdContext, (unsigned char *) &b, 1); } + if (digest) + MD5Update (&mdContext, (unsigned char *) &b, 1); if (skip < 1) { b = bits & 0xff; if (! skip_crs || b != '\r') { charstring_push_back (decoded_c, b); } - if (digest) { MD5Update (&mdContext, (unsigned char *) &b, 1); } + if (digest) + MD5Update (&mdContext, (unsigned char *) &b, 1); } } @@ -297,24 +316,24 @@ test_end: break; case '=': - if (++skip > 3) { - self_delimiting = 1; - break; - } else { + if (++skip <= 3) goto test_end; - } + self_delimiting = 1; + break; } } if (! self_delimiting && bitno != 18) { - advise (NULL, "premature ending (bitno %d) in %s", bitno, encoded); + /* Show some context for the error. */ + cp -= min(cp - encoded, 20); + inform("premature ending (bitno %d) near %s", bitno, cp); charstring_free (decoded_c); *decoded = NULL; return NOTOK; } - *decoded = charstring_buffer_copy (decoded_c); + *decoded = (unsigned char *) charstring_buffer_copy (decoded_c); *len = charstring_bytes (decoded_c); charstring_free (decoded_c); @@ -324,3 +343,35 @@ test_end: return OK; } + + +/* + * Prepare an unsigned char array for display by replacing non-printable + * ASCII bytes with their hex representation. Assumes ASCII input. output + * is allocated by the function and must be freed by the caller. + */ +void +hexify (const unsigned char *input, size_t len, char **output) { + /* Start with a charstring capacity that's arbitrarily larger than len. */ + const charstring_t tmp = charstring_create (2 * len); + const unsigned char *cp = input; + size_t i; + + for (i = 0; i < len; ++i, ++cp) { + if (isascii(*cp) && isprint(*cp)) { + charstring_push_back (tmp, (const char) *cp); + } else { + char s[16]; + const int num = snprintf(s, sizeof s, "[0x%02x]", *cp); + + if (num <= 0 || (unsigned int) num >= sizeof s) { + inform("hexify failed to write nonprintable character, needed %d bytes", num + 1); + } else { + charstring_append_cstring (tmp, s); + } + } + } + + *output = charstring_buffer_copy (tmp); + charstring_free (tmp); +}