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| 1 | +/* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| 2 | + * |
| 3 | + * LibTomCrypt is a library that provides various cryptographic |
| 4 | + * algorithms in a highly modular and flexible manner. |
| 5 | + * |
| 6 | + * The library is free for all purposes without any express |
| 7 | + * guarantee it works. |
| 8 | + */ |
| 9 | +#include "tomcrypt_private.h" |
| 10 | +#include <stdarg.h> |
| 11 | + |
| 12 | +/** |
| 13 | + @file ssh_decode_sequence_multi.c |
| 14 | + SSH data type representation as per RFC4251, Russ Williams |
| 15 | +*/ |
| 16 | + |
| 17 | +#ifdef LTC_SSH |
| 18 | + |
| 19 | +/** |
| 20 | + Decode a SSH sequence using a VA list |
| 21 | + @param in Data to decode |
| 22 | + @param inlen Length of buffer to decode |
| 23 | + @remark <...> is of the form <type, data> (int, void*) except for string <type, data, size> |
| 24 | + @return CRYPT_OK on success |
| 25 | +*/ |
| 26 | +int ssh_decode_sequence_multi(const unsigned char *in, unsigned long inlen, ...) |
| 27 | +{ |
| 28 | + int err; |
| 29 | + va_list args; |
| 30 | + ssh_data_type type; |
| 31 | + void *vdata; |
| 32 | + unsigned char *cdata; |
| 33 | + char *sdata; |
| 34 | + ulong32 *u32data; |
| 35 | + ulong64 *u64data; |
| 36 | + unsigned long size, bufsize; |
| 37 | + |
| 38 | + LTC_ARGCHK(in != NULL); |
| 39 | + |
| 40 | + /* Decode values from buffer */ |
| 41 | + va_start(args, inlen); |
| 42 | + while ((type = (ssh_data_type)va_arg(args, int)) != LTC_SSHDATA_EOL) { |
| 43 | + /* Size of length field */ |
| 44 | + if (type == LTC_SSHDATA_STRING || |
| 45 | + type == LTC_SSHDATA_NAMELIST || |
| 46 | + type == LTC_SSHDATA_MPINT) |
| 47 | + { |
| 48 | + /* Check we'll not read too far */ |
| 49 | + if (inlen < 4) { |
| 50 | + err = CRYPT_BUFFER_OVERFLOW; |
| 51 | + goto error; |
| 52 | + } |
| 53 | + } |
| 54 | + |
| 55 | + /* Calculate (or read) length of data */ |
| 56 | + switch (type) { |
| 57 | + case LTC_SSHDATA_BYTE: |
| 58 | + case LTC_SSHDATA_BOOLEAN: |
| 59 | + size = 1; |
| 60 | + break; |
| 61 | + case LTC_SSHDATA_UINT32: |
| 62 | + size = 4; |
| 63 | + break; |
| 64 | + case LTC_SSHDATA_UINT64: |
| 65 | + size = 8; |
| 66 | + break; |
| 67 | + case LTC_SSHDATA_STRING: |
| 68 | + case LTC_SSHDATA_NAMELIST: |
| 69 | + case LTC_SSHDATA_MPINT: |
| 70 | + LOAD32H(size, in); |
| 71 | + in += 4; |
| 72 | + inlen -= 4; |
| 73 | + break; |
| 74 | + |
| 75 | + case LTC_SSHDATA_EOL: |
| 76 | + /* Should never get here */ |
| 77 | + err = CRYPT_INVALID_ARG; |
| 78 | + goto error; |
| 79 | + } |
| 80 | + |
| 81 | + /* Check we'll not read too far */ |
| 82 | + if (inlen < size) { |
| 83 | + err = CRYPT_BUFFER_OVERFLOW; |
| 84 | + goto error; |
| 85 | + } else { |
| 86 | + inlen -= size; |
| 87 | + } |
| 88 | + |
| 89 | + /* Read data */ |
| 90 | + switch (type) { |
| 91 | + case LTC_SSHDATA_BYTE: |
| 92 | + cdata = va_arg(args, unsigned char*); |
| 93 | + *cdata = *in++; |
| 94 | + break; |
| 95 | + case LTC_SSHDATA_BOOLEAN: |
| 96 | + cdata = va_arg(args, unsigned char*); |
| 97 | + /* |
| 98 | + The value 0 represents FALSE, and the value 1 represents TRUE. All non-zero values MUST be |
| 99 | + interpreted as TRUE; however, applications MUST NOT store values other than 0 and 1. |
| 100 | + */ |
| 101 | + *cdata = (*in++)?1:0; |
| 102 | + break; |
| 103 | + case LTC_SSHDATA_UINT32: |
| 104 | + u32data = va_arg(args, ulong32*); |
| 105 | + LOAD32H(*u32data, in); |
| 106 | + in += 4; |
| 107 | + break; |
| 108 | + case LTC_SSHDATA_UINT64: |
| 109 | + u64data = va_arg(args, ulong64*); |
| 110 | + LOAD64H(*u64data, in); |
| 111 | + in += 8; |
| 112 | + break; |
| 113 | + case LTC_SSHDATA_STRING: |
| 114 | + case LTC_SSHDATA_NAMELIST: |
| 115 | + sdata = va_arg(args, char*); |
| 116 | + bufsize = va_arg(args, unsigned long); |
| 117 | + if (size > 0) { |
| 118 | + if (size >= bufsize) { |
| 119 | + err = CRYPT_BUFFER_OVERFLOW; |
| 120 | + goto error; |
| 121 | + } |
| 122 | + XSTRNCPY(sdata, (const char *)in, size); |
| 123 | + sdata[size] = '\0'; /* strncpy doesn't NUL-terminate */ |
| 124 | + } else { |
| 125 | + *sdata = '\0'; |
| 126 | + } |
| 127 | + in += size; |
| 128 | + break; |
| 129 | + case LTC_SSHDATA_MPINT: |
| 130 | + vdata = va_arg(args, void*); |
| 131 | + if (size == 0) { |
| 132 | + if ((err = mp_set(vdata, 0)) != CRYPT_OK) { goto error; } |
| 133 | + } else { |
| 134 | + if ((err = mp_read_unsigned_bin(vdata, (unsigned char *)in, size)) != CRYPT_OK) { goto error; } |
| 135 | + } |
| 136 | + in += size; |
| 137 | + break; |
| 138 | + |
| 139 | + case LTC_SSHDATA_EOL: |
| 140 | + /* Should never get here */ |
| 141 | + err = CRYPT_INVALID_ARG; |
| 142 | + goto error; |
| 143 | + } |
| 144 | + } |
| 145 | + err = CRYPT_OK; |
| 146 | + |
| 147 | +error: |
| 148 | + va_end(args); |
| 149 | + return err; |
| 150 | +} |
| 151 | + |
| 152 | +#endif |
| 153 | + |
| 154 | +/* ref: $Format:%D$ */ |
| 155 | +/* git commit: $Format:%H$ */ |
| 156 | +/* commit time: $Format:%ai$ */ |
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