-int base64_decode(char const *src, unsigned char *target, size_t targsize)
-{
- unsigned int tarindex, state;
- int ch;
- char *pos;
-
- state = 0;
- tarindex = 0;
-
- while ((ch = *src++) != '\0') {
- if (para_isspace(ch)) /* Skip whitespace anywhere. */
- continue;
-
- if (ch == Pad64)
- break;
-
- pos = strchr(Base64, ch);
- if (pos == NULL) /* A non-base64 character. */
- return -E_BASE64;
-
- switch (state) {
- case 0:
- if (tarindex >= targsize)
- return -E_BASE64;
- target[tarindex] = (pos - Base64) << 2;
- state = 1;
- break;
- case 1:
- if (tarindex + 1 >= targsize)
- return -E_BASE64;
- target[tarindex] |= (pos - Base64) >> 4;
- target[tarindex + 1] = ((pos - Base64) & 0x0f) << 4;
- tarindex++;
- state = 2;
- break;
- case 2:
- if (tarindex + 1 >= targsize)
- return -E_BASE64;
- target[tarindex] |= (pos - Base64) >> 2;
- target[tarindex + 1] = ((pos - Base64) & 0x03) << 6;
- tarindex++;
- state = 3;
- break;
- case 3:
- if (tarindex >= targsize)
- return -E_BASE64;
- target[tarindex] |= pos - Base64;
- tarindex++;
- state = 0;
- break;
- }
- }
-
- /*
- * We are done decoding Base-64 chars. Let's see if we ended
- * on a byte boundary, and/or with erroneous trailing characters.
- */
-
- if (ch == Pad64) { /* We got a pad char. */
- ch = *src++; /* Skip it, get next. */
- switch (state) {
- case 0: /* Invalid = in first position */
- case 1: /* Invalid = in second position */
- return -E_BASE64;
-
- case 2: /* Valid, means one byte of info */
- /* Skip any number of spaces. */
- for (; ch != '\0'; ch = *src++)
- if (!isspace(ch))
- break;
- /* Make sure there is another trailing = sign. */
- if (ch != Pad64)
- return -E_BASE64;
- ch = *src++; /* Skip the = */
- /* Fall through to "single trailing =" case. */
- /* FALLTHROUGH */
-
- case 3: /* Valid, means two bytes of info */
- /*
- * We know this char is an =. Is there anything but
- * whitespace after it?
- */
- for (; ch != '\0'; ch = *src++)
- if (!isspace(ch))
- return -E_BASE64;
-
- /*
- * Now make sure for cases 2 and 3 that the "extra"
- * bits that slopped past the last full byte were
- * zeros. If we don't check them, they become a
- * subliminal channel.
- */
- if (target[tarindex] != 0)
- return -E_BASE64;
- }
- } else {
- /*
- * We ended by seeing the end of the string. Make sure we
- * have no partial bytes lying around.
- */
- if (state != 0)
- return -E_BASE64;
- }
-
- return tarindex;
-}
-
-/**
- * uudecode a buffer.
- *
- * \param src The buffer to decode.
- * \param target Result buffer.
- * \param targsize The length of \a target in bytes.
- *
- * This is just a simple wrapper for base64_decode() which strips whitespace.
- *
- * \return The return value of the underlying call to base64_decode().
- */
-int uudecode(const char *src, unsigned char *target, size_t targsize)
-{
- int len;
- char *encoded, *p;
-
- /* copy the 'readonly' source */
- encoded = para_strdup(src);
- /* skip whitespace and data */
- for (p = encoded; *p == ' ' || *p == '\t'; p++)
- ;
- for (; *p != '\0' && *p != ' ' && *p != '\t'; p++)
- ;
- /* and remove trailing whitespace because base64_decode needs this */
- *p = '\0';
- len = base64_decode(encoded, target, targsize);
- free(encoded);
- return len;
-}
-
-/**
- * Read a 4-byte number from a buffer in big-endian format.
- *
- * \param vp The buffer.
- *
- * The byte-order of the buffer is expected to be big-endian, unlike read_u32()
- * of portable_io.h which expects little endian.
- *
- * \return The 32 bit number given by \a vp.
- */
-uint32_t read_ssh_u32(const void *vp)
-{
- const unsigned char *p = (const unsigned char *)vp;
- uint32_t v;
-
- v = (uint32_t)p[0] << 24;
- v |= (uint32_t)p[1] << 16;
- v |= (uint32_t)p[2] << 8;
- v |= (uint32_t)p[3];
-
- return v;
-}
-
-/**
- * Sanity checks for the header of an ssh key.
- *
- * \param blob The buffer.
- * \param blen The number of bytes of \a blob.
- *
- * This performs some checks to make sure we really have an ssh key. It also
- * computes the offset in bytes of the start of the key values (modulus,
- * exponent..).
- *
- * \return The number of bytes to skip until the start of the first encoded
- * number (usually 11).
- */
-int check_ssh_key_header(const unsigned char *blob, int blen)