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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-10 19:59:03 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-10 19:59:03 +0000 |
commit | a848231ae0f346dc7cc000973fbeb65b0894ee92 (patch) | |
tree | 44b60b367c86723cc78383ef247885d72b388afe /src/util/base32_code.c | |
parent | Initial commit. (diff) | |
download | postfix-a848231ae0f346dc7cc000973fbeb65b0894ee92.tar.xz postfix-a848231ae0f346dc7cc000973fbeb65b0894ee92.zip |
Adding upstream version 3.8.5.upstream/3.8.5
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/util/base32_code.c')
-rw-r--r-- | src/util/base32_code.c | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/src/util/base32_code.c b/src/util/base32_code.c new file mode 100644 index 0000000..31566ea --- /dev/null +++ b/src/util/base32_code.c @@ -0,0 +1,266 @@ +/*++ +/* NAME +/* base32_code 3 +/* SUMMARY +/* encode/decode data, base 32 style +/* SYNOPSIS +/* #include <base32_code.h> +/* +/* VSTRING *base32_encode(result, in, len) +/* VSTRING *result; +/* const char *in; +/* ssize_t len; +/* +/* VSTRING *base32_decode(result, in, len) +/* VSTRING *result; +/* const char *in; +/* ssize_t len; +/* DESCRIPTION +/* base32_encode() takes a block of len bytes and encodes it as one +/* null-terminated string. The result value is the result argument. +/* +/* base32_decode() performs the opposite transformation. The result +/* value is the result argument. The result is null terminated, whether +/* or not that makes sense. +/* DIAGNOSTICS +/* base32_decode() returns a null pointer when the input contains +/* characters not in the base 32 alphabet. +/* SEE ALSO +/* RFC 4648; padding is strictly enforced +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include "sys_defs.h" +#include <ctype.h> +#include <string.h> +#include <limits.h> + +#ifndef UCHAR_MAX +#define UCHAR_MAX 0xff +#endif + +/* Utility library. */ + +#include <msg.h> +#include <mymalloc.h> +#include <vstring.h> +#include <base32_code.h> + +/* Application-specific. */ + +static unsigned char to_b32[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"; + +#define UNSIG_CHAR_PTR(x) ((unsigned char *)(x)) + +/* base32_encode - raw data to encoded */ + +VSTRING *base32_encode(VSTRING *result, const char *in, ssize_t len) +{ + const unsigned char *cp; + ssize_t count; + static int pad_count[] = {0, 6, 4, 3, 1}; + + /* + * Encode 5 -> 8. + */ + VSTRING_RESET(result); + for (cp = UNSIG_CHAR_PTR(in), count = len; count > 0; count -= 5, cp += 5) { + VSTRING_ADDCH(result, to_b32[cp[0] >> 3]); + if (count < 2) { + VSTRING_ADDCH(result, to_b32[(cp[0] & 0x7) << 2]); + break; + } + VSTRING_ADDCH(result, to_b32[(cp[0] & 0x7) << 2 | cp[1] >> 6]); + VSTRING_ADDCH(result, to_b32[(cp[1] & 0x3f) >> 1]); + if (count < 3) { + VSTRING_ADDCH(result, to_b32[(cp[1] & 0x1) << 4]); + break; + } + VSTRING_ADDCH(result, to_b32[(cp[1] & 0x1) << 4 | cp[2] >> 4]); + if (count < 4) { + VSTRING_ADDCH(result, to_b32[(cp[2] & 0xf) << 1]); + break; + } + VSTRING_ADDCH(result, to_b32[(cp[2] & 0xf) << 1 | cp[3] >> 7]); + VSTRING_ADDCH(result, to_b32[(cp[3] & 0x7f) >> 2]); + if (count < 5) { + VSTRING_ADDCH(result, to_b32[(cp[3] & 0x3) << 3]); + break; + } + VSTRING_ADDCH(result, to_b32[(cp[3] & 0x3) << 3 | cp[4] >> 5]); + VSTRING_ADDCH(result, to_b32[cp[4] & 0x1f]); + } + if (count > 0) + vstring_strncat(result, "======", pad_count[count]); + VSTRING_TERMINATE(result); + return (result); +} + +/* base32_decode - encoded data to raw */ + +VSTRING *base32_decode(VSTRING *result, const char *in, ssize_t len) +{ + static unsigned char *un_b32 = 0; + const unsigned char *cp; + ssize_t count; + unsigned int ch0; + unsigned int ch1; + unsigned int ch2; + unsigned int ch3; + unsigned int ch4; + unsigned int ch5; + unsigned int ch6; + unsigned int ch7; + +#define CHARS_PER_BYTE (UCHAR_MAX + 1) +#define INVALID 0xff +#if 1 +#define ENFORCE_LENGTH(x) (x) +#define ENFORCE_PADDING(x) (x) +#define ENFORCE_NULL_BITS(x) (x) +#else +#define ENFORCE_LENGTH(x) (1) +#define ENFORCE_PADDING(x) (1) +#define ENFORCE_NULL_BITS(x) (1) +#endif + + /* + * Sanity check. + */ + if (ENFORCE_LENGTH(len % 8)) + return (0); + + /* + * Once: initialize the decoding lookup table on the fly. + */ + if (un_b32 == 0) { + un_b32 = (unsigned char *) mymalloc(CHARS_PER_BYTE); + memset(un_b32, INVALID, CHARS_PER_BYTE); + for (cp = to_b32; cp < to_b32 + sizeof(to_b32) - 1; cp++) + un_b32[*cp] = cp - to_b32; + } + + /* + * Decode 8 -> 5. + */ + VSTRING_RESET(result); + for (cp = UNSIG_CHAR_PTR(in), count = 0; count < len; count += 8) { + if ((ch0 = un_b32[*cp++]) == INVALID + || (ch1 = un_b32[*cp++]) == INVALID) + return (0); + VSTRING_ADDCH(result, ch0 << 3 | ch1 >> 2); + if ((ch2 = *cp++) == '=' + && ENFORCE_PADDING(strcmp((char *) cp, "=====") == 0) + && ENFORCE_NULL_BITS((ch1 & 0x3) == 0)) + break; + if ((ch2 = un_b32[ch2]) == INVALID) + return (0); + if ((ch3 = un_b32[*cp++]) == INVALID) + return (0); + VSTRING_ADDCH(result, ch1 << 6 | ch2 << 1 | ch3 >> 4); + if ((ch4 = *cp++) == '=' + && ENFORCE_PADDING(strcmp((char *) cp, "===") == 0) + && ENFORCE_NULL_BITS((ch3 & 0xf) == 0)) + break; + if ((ch4 = un_b32[ch4]) == INVALID) + return (0); + VSTRING_ADDCH(result, ch3 << 4 | ch4 >> 1); + if ((ch5 = *cp++) == '=' + && ENFORCE_PADDING(strcmp((char *) cp, "==") == 0) + && ENFORCE_NULL_BITS((ch4 & 0x1) == 0)) + break; + if ((ch5 = un_b32[ch5]) == INVALID) + return (0); + if ((ch6 = un_b32[*cp++]) == INVALID) + return (0); + VSTRING_ADDCH(result, ch4 << 7 | ch5 << 2 | ch6 >> 3); + if ((ch7 = *cp++) == '=' + && ENFORCE_NULL_BITS((ch6 & 0x7) == 0)) + break; + if ((ch7 = un_b32[ch7]) == INVALID) + return (0); + VSTRING_ADDCH(result, ch6 << 5 | ch7); + } + VSTRING_TERMINATE(result); + return (result); +} + +#ifdef TEST + + /* + * Proof-of-concept test program: convert to base 32 and back. + */ + +#define STR(x) vstring_str(x) +#define LEN(x) VSTRING_LEN(x) + +int main(int unused_argc, char **unused_argv) +{ + VSTRING *b1 = vstring_alloc(1); + VSTRING *b2 = vstring_alloc(1); + VSTRING *test = vstring_alloc(1); + int i, j; + + /* + * Test all byte values (except null) on all byte positions. + */ + for (j = 0; j < 256; j++) + for (i = 1; i < 256; i++) + VSTRING_ADDCH(test, i); + VSTRING_TERMINATE(test); + +#define DECODE(b,x,l) { \ + if (base32_decode((b),(x),(l)) == 0) \ + msg_panic("bad base32: %s", (x)); \ + } +#define VERIFY(b,t,l) { \ + if (memcmp((b), (t), (l)) != 0) \ + msg_panic("bad test: %s", (b)); \ + } + + /* + * Test all padding variants. + */ + for (i = 1; i <= 8; i++) { + base32_encode(b1, STR(test), LEN(test)); + DECODE(b2, STR(b1), LEN(b1)); + VERIFY(STR(b2), STR(test), LEN(test)); + + base32_encode(b1, STR(test), LEN(test)); + base32_encode(b2, STR(b1), LEN(b1)); + base32_encode(b1, STR(b2), LEN(b2)); + DECODE(b2, STR(b1), LEN(b1)); + DECODE(b1, STR(b2), LEN(b2)); + DECODE(b2, STR(b1), LEN(b1)); + VERIFY(STR(b2), STR(test), LEN(test)); + + base32_encode(b1, STR(test), LEN(test)); + base32_encode(b2, STR(b1), LEN(b1)); + base32_encode(b1, STR(b2), LEN(b2)); + base32_encode(b2, STR(b1), LEN(b1)); + base32_encode(b1, STR(b2), LEN(b2)); + DECODE(b2, STR(b1), LEN(b1)); + DECODE(b1, STR(b2), LEN(b2)); + DECODE(b2, STR(b1), LEN(b1)); + DECODE(b1, STR(b2), LEN(b2)); + DECODE(b2, STR(b1), LEN(b1)); + VERIFY(STR(b2), STR(test), LEN(test)); + vstring_truncate(test, LEN(test) - 1); + } + vstring_free(test); + vstring_free(b1); + vstring_free(b2); + return (0); +} + +#endif |