| // SPDX-License-Identifier: BSD-2-Clause |
| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| */ |
| #include "tomcrypt_private.h" |
| #include <stdarg.h> |
| |
| /** |
| @file ssh_decode_sequence_multi.c |
| SSH data type representation as per RFC4251, Russ Williams |
| */ |
| |
| #ifdef LTC_SSH |
| |
| /** |
| Decode a SSH sequence using a VA list |
| @param in Data to decode |
| @param inlen Length of buffer to decode |
| @remark <...> is of the form <type, data> (int, void*) except for string <type, data, size> |
| @return CRYPT_OK on success |
| */ |
| int ssh_decode_sequence_multi(const unsigned char *in, unsigned long inlen, ...) |
| { |
| int err; |
| va_list args; |
| ssh_data_type type; |
| void *vdata; |
| unsigned char *cdata; |
| char *sdata; |
| ulong32 *u32data; |
| ulong64 *u64data; |
| unsigned long bufsize; |
| ulong32 size; |
| |
| LTC_ARGCHK(in != NULL); |
| |
| /* Decode values from buffer */ |
| va_start(args, inlen); |
| while ((type = (ssh_data_type)va_arg(args, int)) != LTC_SSHDATA_EOL) { |
| /* Size of length field */ |
| if (type == LTC_SSHDATA_STRING || |
| type == LTC_SSHDATA_NAMELIST || |
| type == LTC_SSHDATA_MPINT) |
| { |
| /* Check we'll not read too far */ |
| if (inlen < 4) { |
| err = CRYPT_BUFFER_OVERFLOW; |
| goto error; |
| } |
| } |
| |
| /* Calculate (or read) length of data */ |
| size = 0xFFFFFFFFU; |
| switch (type) { |
| case LTC_SSHDATA_BYTE: |
| case LTC_SSHDATA_BOOLEAN: |
| size = 1; |
| break; |
| case LTC_SSHDATA_UINT32: |
| size = 4; |
| break; |
| case LTC_SSHDATA_UINT64: |
| size = 8; |
| break; |
| case LTC_SSHDATA_STRING: |
| case LTC_SSHDATA_NAMELIST: |
| case LTC_SSHDATA_MPINT: |
| LOAD32H(size, in); |
| in += 4; |
| inlen -= 4; |
| break; |
| |
| case LTC_SSHDATA_EOL: |
| default: |
| /* Should never get here */ |
| err = CRYPT_INVALID_ARG; |
| goto error; |
| } |
| |
| /* Check we'll not read too far */ |
| if (inlen < size) { |
| err = CRYPT_BUFFER_OVERFLOW; |
| goto error; |
| } else { |
| inlen -= size; |
| } |
| |
| /* Read data */ |
| switch (type) { |
| case LTC_SSHDATA_BYTE: |
| cdata = va_arg(args, unsigned char*); |
| *cdata = *in++; |
| break; |
| case LTC_SSHDATA_BOOLEAN: |
| cdata = va_arg(args, unsigned char*); |
| /* |
| The value 0 represents FALSE, and the value 1 represents TRUE. All non-zero values MUST be |
| interpreted as TRUE; however, applications MUST NOT store values other than 0 and 1. |
| */ |
| *cdata = (*in++)?1:0; |
| break; |
| case LTC_SSHDATA_UINT32: |
| u32data = va_arg(args, ulong32*); |
| LOAD32H(*u32data, in); |
| in += 4; |
| break; |
| case LTC_SSHDATA_UINT64: |
| u64data = va_arg(args, ulong64*); |
| LOAD64H(*u64data, in); |
| in += 8; |
| break; |
| case LTC_SSHDATA_STRING: |
| case LTC_SSHDATA_NAMELIST: |
| sdata = va_arg(args, char*); |
| bufsize = va_arg(args, unsigned long); |
| if (size >= bufsize) { |
| err = CRYPT_BUFFER_OVERFLOW; |
| goto error; |
| } |
| if (size > 0) { |
| XSTRNCPY(sdata, (const char *)in, size); |
| sdata[size] = '\0'; /* strncpy doesn't NUL-terminate */ |
| } else { |
| *sdata = '\0'; |
| } |
| in += size; |
| break; |
| case LTC_SSHDATA_MPINT: |
| vdata = va_arg(args, void*); |
| if (size == 0) { |
| if ((err = mp_set(vdata, 0)) != CRYPT_OK) { goto error; } |
| } else if ((in[0] & 0x80) != 0) { |
| /* Negative number - not supported */ |
| err = CRYPT_INVALID_PACKET; |
| goto error; |
| } else { |
| if ((err = mp_read_unsigned_bin(vdata, (unsigned char *)in, size)) != CRYPT_OK) { goto error; } |
| } |
| in += size; |
| break; |
| |
| case LTC_SSHDATA_EOL: |
| default: |
| /* Should never get here */ |
| err = CRYPT_INVALID_ARG; |
| goto error; |
| } |
| } |
| err = CRYPT_OK; |
| |
| error: |
| va_end(args); |
| return err; |
| } |
| |
| #endif |
| |
| /* ref: $Format:%D$ */ |
| /* git commit: $Format:%H$ */ |
| /* commit time: $Format:%ai$ */ |