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Diffstat (limited to 'source4/lib/util/asn1.c')
| -rw-r--r-- | source4/lib/util/asn1.c | 770 |
1 files changed, 770 insertions, 0 deletions
diff --git a/source4/lib/util/asn1.c b/source4/lib/util/asn1.c new file mode 100644 index 0000000000..4756c0640d --- /dev/null +++ b/source4/lib/util/asn1.c @@ -0,0 +1,770 @@ +/* + Unix SMB/CIFS implementation. + simple ASN1 routines + Copyright (C) Andrew Tridgell 2001 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "includes.h" +#include "lib/util/asn1.h" + +/* allocate an asn1 structure */ +struct asn1_data *asn1_init(TALLOC_CTX *mem_ctx) +{ + struct asn1_data *ret = talloc_zero(mem_ctx, struct asn1_data); + if (ret == NULL) { + DEBUG(0,("asn1_init failed! out of memory\n")); + } + return ret; +} + +/* free an asn1 structure */ +void asn1_free(struct asn1_data *data) +{ + talloc_free(data); +} + +/* write to the ASN1 buffer, advancing the buffer pointer */ +bool asn1_write(struct asn1_data *data, const void *p, int len) +{ + if (data->has_error) return false; + if (data->length < data->ofs+len) { + uint8_t *newp; + newp = talloc_realloc(data, data->data, uint8_t, data->ofs+len); + if (!newp) { + asn1_free(data); + data->has_error = true; + return false; + } + data->data = newp; + data->length = data->ofs+len; + } + memcpy(data->data + data->ofs, p, len); + data->ofs += len; + return true; +} + +/* useful fn for writing a uint8_t */ +bool asn1_write_uint8(struct asn1_data *data, uint8_t v) +{ + return asn1_write(data, &v, 1); +} + +/* push a tag onto the asn1 data buffer. Used for nested structures */ +bool asn1_push_tag(struct asn1_data *data, uint8_t tag) +{ + struct nesting *nesting; + + asn1_write_uint8(data, tag); + nesting = talloc(data, struct nesting); + if (!nesting) { + data->has_error = true; + return false; + } + + nesting->start = data->ofs; + nesting->next = data->nesting; + data->nesting = nesting; + return asn1_write_uint8(data, 0xff); +} + +/* pop a tag */ +bool asn1_pop_tag(struct asn1_data *data) +{ + struct nesting *nesting; + size_t len; + + nesting = data->nesting; + + if (!nesting) { + data->has_error = true; + return false; + } + len = data->ofs - (nesting->start+1); + /* yes, this is ugly. We don't know in advance how many bytes the length + of a tag will take, so we assumed 1 byte. If we were wrong then we + need to correct our mistake */ + if (len > 0xFFFFFF) { + data->data[nesting->start] = 0x84; + if (!asn1_write_uint8(data, 0)) return false; + if (!asn1_write_uint8(data, 0)) return false; + if (!asn1_write_uint8(data, 0)) return false; + if (!asn1_write_uint8(data, 0)) return false; + memmove(data->data+nesting->start+5, data->data+nesting->start+1, len); + data->data[nesting->start+1] = (len>>24) & 0xFF; + data->data[nesting->start+2] = (len>>16) & 0xFF; + data->data[nesting->start+3] = (len>>8) & 0xFF; + data->data[nesting->start+4] = len&0xff; + } else if (len > 0xFFFF) { + data->data[nesting->start] = 0x83; + if (!asn1_write_uint8(data, 0)) return false; + if (!asn1_write_uint8(data, 0)) return false; + if (!asn1_write_uint8(data, 0)) return false; + memmove(data->data+nesting->start+4, data->data+nesting->start+1, len); + data->data[nesting->start+1] = (len>>16) & 0xFF; + data->data[nesting->start+2] = (len>>8) & 0xFF; + data->data[nesting->start+3] = len&0xff; + } else if (len > 255) { + data->data[nesting->start] = 0x82; + if (!asn1_write_uint8(data, 0)) return false; + if (!asn1_write_uint8(data, 0)) return false; + memmove(data->data+nesting->start+3, data->data+nesting->start+1, len); + data->data[nesting->start+1] = len>>8; + data->data[nesting->start+2] = len&0xff; + } else if (len > 127) { + data->data[nesting->start] = 0x81; + if (!asn1_write_uint8(data, 0)) return false; + memmove(data->data+nesting->start+2, data->data+nesting->start+1, len); + data->data[nesting->start+1] = len; + } else { + data->data[nesting->start] = len; + } + + data->nesting = nesting->next; + talloc_free(nesting); + return true; +} + +/* "i" is the one's complement representation, as is the normal result of an + * implicit signed->unsigned conversion */ + +static bool push_int_bigendian(struct asn1_data *data, unsigned int i, bool negative) +{ + uint8_t lowest = i & 0xFF; + + i = i >> 8; + if (i != 0) + if (!push_int_bigendian(data, i, negative)) + return false; + + if (data->nesting->start+1 == data->ofs) { + + /* We did not write anything yet, looking at the highest + * valued byte */ + + if (negative) { + /* Don't write leading 0xff's */ + if (lowest == 0xFF) + return true; + + if ((lowest & 0x80) == 0) { + /* The only exception for a leading 0xff is if + * the highest bit is 0, which would indicate + * a positive value */ + if (!asn1_write_uint8(data, 0xff)) + return false; + } + } else { + if (lowest & 0x80) { + /* The highest bit of a positive integer is 1, + * this would indicate a negative number. Push + * a 0 to indicate a positive one */ + if (!asn1_write_uint8(data, 0)) + return false; + } + } + } + + return asn1_write_uint8(data, lowest); +} + +/* write an Integer without the tag framing. Needed for example for the LDAP + * Abandon Operation */ + +bool asn1_write_implicit_Integer(struct asn1_data *data, int i) +{ + if (i == -1) { + /* -1 is special as it consists of all-0xff bytes. In + push_int_bigendian this is the only case that is not + properly handled, as all 0xff bytes would be handled as + leading ones to be ignored. */ + return asn1_write_uint8(data, 0xff); + } else { + return push_int_bigendian(data, i, i<0); + } +} + + +/* write an integer */ +bool asn1_write_Integer(struct asn1_data *data, int i) +{ + if (!asn1_push_tag(data, ASN1_INTEGER)) return false; + if (!asn1_write_implicit_Integer(data, i)) return false; + return asn1_pop_tag(data); +} + +bool ber_write_OID_String(DATA_BLOB *blob, const char *OID) +{ + uint_t v, v2; + const char *p = (const char *)OID; + char *newp; + int i; + + v = strtoul(p, &newp, 10); + if (newp[0] != '.') return false; + p = newp + 1; + + v2 = strtoul(p, &newp, 10); + if (newp[0] != '.') return false; + p = newp + 1; + + /*the ber representation can't use more space then the string one */ + *blob = data_blob(NULL, strlen(OID)); + if (!blob->data) return false; + + blob->data[0] = 40*v + v2; + + i = 1; + while (*p) { + v = strtoul(p, &newp, 10); + if (newp[0] == '.') { + p = newp + 1; + } else if (newp[0] == '\0') { + p = newp; + } else { + data_blob_free(blob); + return false; + } + if (v >= (1<<28)) blob->data[i++] = (0x80 | ((v>>28)&0x7f)); + if (v >= (1<<21)) blob->data[i++] = (0x80 | ((v>>21)&0x7f)); + if (v >= (1<<14)) blob->data[i++] = (0x80 | ((v>>14)&0x7f)); + if (v >= (1<<7)) blob->data[i++] = (0x80 | ((v>>7)&0x7f)); + blob->data[i++] = (v&0x7f); + } + + blob->length = i; + + return true; +} + +/* write an object ID to a ASN1 buffer */ +bool asn1_write_OID(struct asn1_data *data, const char *OID) +{ + DATA_BLOB blob; + + if (!asn1_push_tag(data, ASN1_OID)) return false; + + if (!ber_write_OID_String(&blob, OID)) { + data->has_error = true; + return false; + } + + if (!asn1_write(data, blob.data, blob.length)) { + data->has_error = true; + return false; + } + data_blob_free(&blob); + return asn1_pop_tag(data); +} + +/* write an octet string */ +bool asn1_write_OctetString(struct asn1_data *data, const void *p, size_t length) +{ + asn1_push_tag(data, ASN1_OCTET_STRING); + asn1_write(data, p, length); + asn1_pop_tag(data); + return !data->has_error; +} + +/* write a LDAP string */ +bool asn1_write_LDAPString(struct asn1_data *data, const char *s) +{ + asn1_write(data, s, strlen(s)); + return !data->has_error; +} + +/* write a LDAP string from a DATA_BLOB */ +bool asn1_write_DATA_BLOB_LDAPString(struct asn1_data *data, const DATA_BLOB *s) +{ + asn1_write(data, s->data, s->length); + return !data->has_error; +} + +/* write a general string */ +bool asn1_write_GeneralString(struct asn1_data *data, const char *s) +{ + asn1_push_tag(data, ASN1_GENERAL_STRING); + asn1_write_LDAPString(data, s); + asn1_pop_tag(data); + return !data->has_error; +} + +bool asn1_write_ContextSimple(struct asn1_data *data, uint8_t num, DATA_BLOB *blob) +{ + asn1_push_tag(data, ASN1_CONTEXT_SIMPLE(num)); + asn1_write(data, blob->data, blob->length); + asn1_pop_tag(data); + return !data->has_error; +} + +/* write a BOOLEAN */ +bool asn1_write_BOOLEAN(struct asn1_data *data, bool v) +{ + asn1_push_tag(data, ASN1_BOOLEAN); + asn1_write_uint8(data, v ? 0xFF : 0); + asn1_pop_tag(data); + return !data->has_error; +} + +bool asn1_read_BOOLEAN(struct asn1_data *data, bool *v) +{ + uint8_t tmp = 0; + asn1_start_tag(data, ASN1_BOOLEAN); + asn1_read_uint8(data, &tmp); + if (tmp == 0xFF) { + *v = true; + } else { + *v = false; + } + asn1_end_tag(data); + return !data->has_error; +} + +/* check a BOOLEAN */ +bool asn1_check_BOOLEAN(struct asn1_data *data, bool v) +{ + uint8_t b = 0; + + asn1_read_uint8(data, &b); + if (b != ASN1_BOOLEAN) { + data->has_error = true; + return false; + } + asn1_read_uint8(data, &b); + if (b != v) { + data->has_error = true; + return false; + } + return !data->has_error; +} + + +/* load a struct asn1_data structure with a lump of data, ready to be parsed */ +bool asn1_load(struct asn1_data *data, DATA_BLOB blob) +{ + ZERO_STRUCTP(data); + data->data = talloc_memdup(data, blob.data, blob.length); + if (!data->data) { + data->has_error = true; + return false; + } + data->length = blob.length; + return true; +} + +/* Peek into an ASN1 buffer, not advancing the pointer */ +bool asn1_peek(struct asn1_data *data, void *p, int len) +{ + if (data->has_error) + return false; + + if (len < 0 || data->ofs + len < data->ofs || data->ofs + len < len) + return false; + + if (data->ofs + len > data->length) { + /* we need to mark the buffer as consumed, so the caller knows + this was an out of data error, and not a decode error */ + data->ofs = data->length; + return false; + } + + memcpy(p, data->data + data->ofs, len); + return true; +} + +/* read from a ASN1 buffer, advancing the buffer pointer */ +bool asn1_read(struct asn1_data *data, void *p, int len) +{ + if (!asn1_peek(data, p, len)) { + data->has_error = true; + return false; + } + + data->ofs += len; + return true; +} + +/* read a uint8_t from a ASN1 buffer */ +bool asn1_read_uint8(struct asn1_data *data, uint8_t *v) +{ + return asn1_read(data, v, 1); +} + +bool asn1_peek_uint8(struct asn1_data *data, uint8_t *v) +{ + return asn1_peek(data, v, 1); +} + +bool asn1_peek_tag(struct asn1_data *data, uint8_t tag) +{ + uint8_t b; + + if (asn1_tag_remaining(data) <= 0) { + return false; + } + + if (!asn1_peek_uint8(data, &b)) + return false; + + return (b == tag); +} + +/* start reading a nested asn1 structure */ +bool asn1_start_tag(struct asn1_data *data, uint8_t tag) +{ + uint8_t b; + struct nesting *nesting; + + if (!asn1_read_uint8(data, &b)) + return false; + + if (b != tag) { + data->has_error = true; + return false; + } + nesting = talloc(data, struct nesting); + if (!nesting) { + data->has_error = true; + return false; + } + + if (!asn1_read_uint8(data, &b)) { + return false; + } + + if (b & 0x80) { + int n = b & 0x7f; + if (!asn1_read_uint8(data, &b)) + return false; + nesting->taglen = b; + while (n > 1) { + if (!asn1_read_uint8(data, &b)) + return false; + nesting->taglen = (nesting->taglen << 8) | b; + n--; + } + } else { + nesting->taglen = b; + } + nesting->start = data->ofs; + nesting->next = data->nesting; + data->nesting = nesting; + if (asn1_tag_remaining(data) == -1) { + return false; + } + return !data->has_error; +} + +/* stop reading a tag */ +bool asn1_end_tag(struct asn1_data *data) +{ + struct nesting *nesting; + + /* make sure we read it all */ + if (asn1_tag_remaining(data) != 0) { + data->has_error = true; + return false; + } + + nesting = data->nesting; + + if (!nesting) { + data->has_error = true; + return false; + } + + data->nesting = nesting->next; + talloc_free(nesting); + return true; +} + +/* work out how many bytes are left in this nested tag */ +int asn1_tag_remaining(struct asn1_data *data) +{ + int remaining; + if (data->has_error) { + return -1; + } + + if (!data->nesting) { + data->has_error = true; + return -1; + } + remaining = data->nesting->taglen - (data->ofs - data->nesting->start); + if (remaining > (data->length - data->ofs)) { + data->has_error = true; + return -1; + } + return remaining; +} + +/* read an object ID from a data blob */ +bool ber_read_OID_String(TALLOC_CTX *mem_ctx, DATA_BLOB blob, const char **OID) +{ + int i; + uint8_t *b; + uint_t v; + char *tmp_oid = NULL; + + if (blob.length < 2) return false; + + b = blob.data; + + tmp_oid = talloc_asprintf(mem_ctx, "%u", b[0]/40); + if (!tmp_oid) goto nomem; + tmp_oid = talloc_asprintf_append_buffer(tmp_oid, ".%u", b[0]%40); + if (!tmp_oid) goto nomem; + + for(i = 1, v = 0; i < blob.length; i++) { + v = (v<<7) | (b[i]&0x7f); + if ( ! (b[i] & 0x80)) { + tmp_oid = talloc_asprintf_append_buffer(tmp_oid, ".%u", v); + v = 0; + } + if (!tmp_oid) goto nomem; + } + + if (v != 0) { + talloc_free(tmp_oid); + return false; + } + + *OID = tmp_oid; + return true; + +nomem: + return false; +} + +/* read an object ID from a ASN1 buffer */ +bool asn1_read_OID(struct asn1_data *data, TALLOC_CTX *mem_ctx, const char **OID) +{ + DATA_BLOB blob; + int len; + + if (!asn1_start_tag(data, ASN1_OID)) return false; + + len = asn1_tag_remaining(data); + if (len < 0) { + data->has_error = true; + return false; + } + + blob = data_blob(NULL, len); + if (!blob.data) { + data->has_error = true; + return false; + } + + asn1_read(data, blob.data, len); + asn1_end_tag(data); + if (data->has_error) { + data_blob_free(&blob); + return false; + } + + if (!ber_read_OID_String(mem_ctx, blob, OID)) { + data->has_error = true; + data_blob_free(&blob); + return false; + } + + data_blob_free(&blob); + return true; +} + +/* check that the next object ID is correct */ +bool asn1_check_OID(struct asn1_data *data, const char *OID) +{ + const char *id; + + if (!asn1_read_OID(data, data, &id)) return false; + + if (strcmp(id, OID) != 0) { + talloc_free(discard_const(id)); + data->has_error = true; + return false; + } + talloc_free(discard_const(id)); + return true; +} + +/* read a LDAPString from a ASN1 buffer */ +bool asn1_read_LDAPString(struct asn1_data *data, TALLOC_CTX *mem_ctx, char **s) +{ + int len; + len = asn1_tag_remaining(data); + if (len < 0) { + data->has_error = true; + return false; + } + *s = talloc_array(mem_ctx, char, len+1); + if (! *s) { + data->has_error = true; + return false; + } + asn1_read(data, *s, len); + (*s)[len] = 0; + return !data->has_error; +} + + +/* read a GeneralString from a ASN1 buffer */ +bool asn1_read_GeneralString(struct asn1_data *data, TALLOC_CTX *mem_ctx, char **s) +{ + if (!asn1_start_tag(data, ASN1_GENERAL_STRING)) return false; + if (!asn1_read_LDAPString(data, mem_ctx, s)) return false; + return asn1_end_tag(data); +} + + +/* read a octet string blob */ +bool asn1_read_OctetString(struct asn1_data *data, TALLOC_CTX *mem_ctx, DATA_BLOB *blob) +{ + int len; + ZERO_STRUCTP(blob); + if (!asn1_start_tag(data, ASN1_OCTET_STRING)) return false; + len = asn1_tag_remaining(data); + if (len < 0) { + data->has_error = true; + return false; + } + *blob = data_blob_talloc(mem_ctx, NULL, len+1); + if (!blob->data) { + data->has_error = true; + return false; + } + asn1_read(data, blob->data, len); + asn1_end_tag(data); + blob->length--; + blob->data[len] = 0; + + if (data->has_error) { + data_blob_free(blob); + *blob = data_blob(NULL, 0); + return false; + } + return true; +} + +bool asn1_read_ContextSimple(struct asn1_data *data, uint8_t num, DATA_BLOB *blob) +{ + int len; + ZERO_STRUCTP(blob); + if (!asn1_start_tag(data, ASN1_CONTEXT_SIMPLE(num))) return false; + len = asn1_tag_remaining(data); + if (len < 0) { + data->has_error = true; + return false; + } + *blob = data_blob(NULL, len); + if ((len != 0) && (!blob->data)) { + data->has_error = true; + return false; + } + asn1_read(data, blob->data, len); + asn1_end_tag(data); + return !data->has_error; +} + +/* read an integer without tag*/ +bool asn1_read_implicit_Integer(struct asn1_data *data, int *i) +{ + uint8_t b; + *i = 0; + + while (!data->has_error && asn1_tag_remaining(data)>0) { + if (!asn1_read_uint8(data, &b)) return false; + *i = (*i << 8) + b; + } + return !data->has_error; + +} + +/* read an integer */ +bool asn1_read_Integer(struct asn1_data *data, int *i) +{ + *i = 0; + + if (!asn1_start_tag(data, ASN1_INTEGER)) return false; + if (!asn1_read_implicit_Integer(data, i)) return false; + return asn1_end_tag(data); +} + +/* read an integer */ +bool asn1_read_enumerated(struct asn1_data *data, int *v) +{ + *v = 0; + + if (!asn1_start_tag(data, ASN1_ENUMERATED)) return false; + while (!data->has_error && asn1_tag_remaining(data)>0) { + uint8_t b; + asn1_read_uint8(data, &b); + *v = (*v << 8) + b; + } + return asn1_end_tag(data); +} + +/* check a enumerated value is correct */ +bool asn1_check_enumerated(struct asn1_data *data, int v) +{ + uint8_t b; + if (!asn1_start_tag(data, ASN1_ENUMERATED)) return false; + asn1_read_uint8(data, &b); + asn1_end_tag(data); + + if (v != b) + data->has_error = false; + + return !data->has_error; +} + +/* write an enumerated value to the stream */ +bool asn1_write_enumerated(struct asn1_data *data, uint8_t v) +{ + if (!asn1_push_tag(data, ASN1_ENUMERATED)) return false; + asn1_write_uint8(data, v); + asn1_pop_tag(data); + return !data->has_error; +} + +/* + check if a ASN.1 blob is a full tag +*/ +NTSTATUS asn1_full_tag(DATA_BLOB blob, uint8_t tag, size_t *packet_size) +{ + struct asn1_data *asn1 = asn1_init(NULL); + int size; + + NT_STATUS_HAVE_NO_MEMORY(asn1); + + asn1->data = blob.data; + asn1->length = blob.length; + asn1_start_tag(asn1, tag); + if (asn1->has_error) { + talloc_free(asn1); + return STATUS_MORE_ENTRIES; + } + size = asn1_tag_remaining(asn1) + asn1->ofs; + + talloc_free(asn1); + + if (size > blob.length) { + return STATUS_MORE_ENTRIES; + } + + *packet_size = size; + return NT_STATUS_OK; +} |