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-rw-r--r--src/util/base32_code.c266
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
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