diff options
Diffstat (limited to 'src/pk/asn1/der/sequence/der_decode_sequence_flexi.c')
| -rw-r--r-- | src/pk/asn1/der/sequence/der_decode_sequence_flexi.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/src/pk/asn1/der/sequence/der_decode_sequence_flexi.c b/src/pk/asn1/der/sequence/der_decode_sequence_flexi.c new file mode 100644 index 0000000..19d8c86 --- /dev/null +++ b/src/pk/asn1/der/sequence/der_decode_sequence_flexi.c @@ -0,0 +1,386 @@ +/* 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. + * + * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com + */ +#include "tomcrypt.h" + +/** + @file der_decode_sequence_flexi.c + ASN.1 DER, decode an array of ASN.1 types with a flexi parser, Tom St Denis +*/ + +#ifdef LTC_DER + +static unsigned long fetch_length(const unsigned char *in, unsigned long inlen) +{ + unsigned long x, y, z; + + y = 0; + + /* skip type and read len */ + if (inlen < 2) { + return 0xFFFFFFFF; + } + ++in; ++y; + + /* read len */ + x = *in++; ++y; + + /* <128 means literal */ + if (x < 128) { + return x+y; + } + x &= 0x7F; /* the lower 7 bits are the length of the length */ + inlen -= 2; + + /* len means len of len! */ + if (x == 0 || x > 4 || x > inlen) { + return 0xFFFFFFFF; + } + + y += x; + z = 0; + while (x--) { + z = (z<<8) | ((unsigned long)*in); + ++in; + } + return z+y; +} + +/** + ASN.1 DER Flexi(ble) decoder will decode arbitrary DER packets and create a linked list of the decoded elements. + @param in The input buffer + @param inlen [in/out] The length of the input buffer and on output the amount of decoded data + @param out [out] A pointer to the linked list + @return CRYPT_OK on success. +*/ +int der_decode_sequence_flexi(const unsigned char *in, unsigned long *inlen, ltc_asn1_list **out) +{ + ltc_asn1_list *l; + unsigned long err, type, len, totlen, x, y; + void *realloc_tmp; + + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(inlen != NULL); + LTC_ARGCHK(out != NULL); + + l = NULL; + totlen = 0; + + /* scan the input and and get lengths and what not */ + while (*inlen) { + /* read the type byte */ + type = *in; + + /* fetch length */ + len = fetch_length(in, *inlen); + if (len > *inlen) { + err = CRYPT_INVALID_PACKET; + goto error; + } + + /* alloc new link */ + if (l == NULL) { + l = XCALLOC(1, sizeof(*l)); + if (l == NULL) { + err = CRYPT_MEM; + goto error; + } + } else { + l->next = XCALLOC(1, sizeof(*l)); + if (l->next == NULL) { + err = CRYPT_MEM; + goto error; + } + l->next->prev = l; + l = l->next; + } + + /* now switch on type */ + switch (type) { + case 0x01: /* BOOLEAN */ + l->type = LTC_ASN1_BOOLEAN; + l->size = 1; + l->data = XCALLOC(1, sizeof(int)); + + if ((err = der_decode_boolean(in, *inlen, l->data)) != CRYPT_OK) { + goto error; + } + + if ((err = der_length_boolean(&len)) != CRYPT_OK) { + goto error; + } + break; + + case 0x02: /* INTEGER */ + /* init field */ + l->type = LTC_ASN1_INTEGER; + l->size = 1; + if ((err = mp_init(&l->data)) != CRYPT_OK) { + goto error; + } + + /* decode field */ + if ((err = der_decode_integer(in, *inlen, l->data)) != CRYPT_OK) { + goto error; + } + + /* calc length of object */ + if ((err = der_length_integer(l->data, &len)) != CRYPT_OK) { + goto error; + } + break; + + case 0x03: /* BIT */ + /* init field */ + l->type = LTC_ASN1_BIT_STRING; + l->size = len * 8; /* *8 because we store decoded bits one per char and they are encoded 8 per char. */ + + if ((l->data = XCALLOC(1, l->size)) == NULL) { + err = CRYPT_MEM; + goto error; + } + + if ((err = der_decode_bit_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { + goto error; + } + + if ((err = der_length_bit_string(l->size, &len)) != CRYPT_OK) { + goto error; + } + break; + + case 0x04: /* OCTET */ + + /* init field */ + l->type = LTC_ASN1_OCTET_STRING; + l->size = len; + + if ((l->data = XCALLOC(1, l->size)) == NULL) { + err = CRYPT_MEM; + goto error; + } + + if ((err = der_decode_octet_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { + goto error; + } + + if ((err = der_length_octet_string(l->size, &len)) != CRYPT_OK) { + goto error; + } + break; + + case 0x05: /* NULL */ + + /* valid NULL is 0x05 0x00 */ + if (in[0] != 0x05 || in[1] != 0x00) { + err = CRYPT_INVALID_PACKET; + goto error; + } + + /* simple to store ;-) */ + l->type = LTC_ASN1_NULL; + l->data = NULL; + l->size = 0; + len = 2; + + break; + + case 0x06: /* OID */ + + /* init field */ + l->type = LTC_ASN1_OBJECT_IDENTIFIER; + l->size = len; + + if ((l->data = XCALLOC(len, sizeof(unsigned long))) == NULL) { + err = CRYPT_MEM; + goto error; + } + + if ((err = der_decode_object_identifier(in, *inlen, l->data, &l->size)) != CRYPT_OK) { + goto error; + } + + if ((err = der_length_object_identifier(l->data, l->size, &len)) != CRYPT_OK) { + goto error; + } + + /* resize it to save a bunch of mem */ + if ((realloc_tmp = XREALLOC(l->data, l->size * sizeof(unsigned long))) == NULL) { + /* out of heap but this is not an error */ + break; + } + l->data = realloc_tmp; + break; + + case 0x0C: /* UTF8 */ + + /* init field */ + l->type = LTC_ASN1_UTF8_STRING; + l->size = len; + + if ((l->data = XCALLOC(sizeof(wchar_t), l->size)) == NULL) { + err = CRYPT_MEM; + goto error; + } + + if ((err = der_decode_utf8_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { + goto error; + } + + if ((err = der_length_utf8_string(l->data, l->size, &len)) != CRYPT_OK) { + goto error; + } + break; + + case 0x13: /* PRINTABLE */ + + /* init field */ + l->type = LTC_ASN1_PRINTABLE_STRING; + l->size = len; + + if ((l->data = XCALLOC(1, l->size)) == NULL) { + err = CRYPT_MEM; + goto error; + } + + if ((err = der_decode_printable_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { + goto error; + } + + if ((err = der_length_printable_string(l->data, l->size, &len)) != CRYPT_OK) { + goto error; + } + break; + + case 0x16: /* IA5 */ + + /* init field */ + l->type = LTC_ASN1_IA5_STRING; + l->size = len; + + if ((l->data = XCALLOC(1, l->size)) == NULL) { + err = CRYPT_MEM; + goto error; + } + + if ((err = der_decode_ia5_string(in, *inlen, l->data, &l->size)) != CRYPT_OK) { + goto error; + } + + if ((err = der_length_ia5_string(l->data, l->size, &len)) != CRYPT_OK) { + goto error; + } + break; + + case 0x17: /* UTC TIME */ + + /* init field */ + l->type = LTC_ASN1_UTCTIME; + l->size = 1; + + if ((l->data = XCALLOC(1, sizeof(ltc_utctime))) == NULL) { + err = CRYPT_MEM; + goto error; + } + + len = *inlen; + if ((err = der_decode_utctime(in, &len, l->data)) != CRYPT_OK) { + goto error; + } + + if ((err = der_length_utctime(l->data, &len)) != CRYPT_OK) { + goto error; + } + break; + + case 0x30: /* SEQUENCE */ + case 0x31: /* SET */ + + /* init field */ + l->type = (type == 0x30) ? LTC_ASN1_SEQUENCE : LTC_ASN1_SET; + + /* we have to decode the SEQUENCE header and get it's length */ + + /* move past type */ + ++in; --(*inlen); + + /* read length byte */ + x = *in++; --(*inlen); + + /* smallest SEQUENCE/SET header */ + y = 2; + + /* now if it's > 127 the next bytes are the length of the length */ + if (x > 128) { + x &= 0x7F; + in += x; + *inlen -= x; + + /* update sequence header len */ + y += x; + } + + /* Sequence elements go as child */ + len = len - y; + if ((err = der_decode_sequence_flexi(in, &len, &(l->child))) != CRYPT_OK) { + goto error; + } + + /* len update */ + totlen += y; + + /* link them up y0 */ + l->child->parent = l; + + break; + default: + /* invalid byte ... this is a soft error */ + /* remove link */ + l = l->prev; + XFREE(l->next); + l->next = NULL; + goto outside; + } + + /* advance pointers */ + totlen += len; + in += len; + *inlen -= len; + } + +outside: + + /* rewind l please */ + while (l->prev != NULL || l->parent != NULL) { + if (l->parent != NULL) { + l = l->parent; + } else { + l = l->prev; + } + } + + /* return */ + *out = l; + *inlen = totlen; + return CRYPT_OK; + +error: + /* free list */ + der_sequence_free(l); + + return err; +} + +#endif + + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/sequence/der_decode_sequence_flexi.c,v $ */ +/* $Revision: 1.25 $ */ +/* $Date: 2006/11/26 02:25:18 $ */ |