diff options
Diffstat (limited to 'source3/libsmb/asn1.c')
| -rw-r--r-- | source3/libsmb/asn1.c | 186 |
1 files changed, 168 insertions, 18 deletions
diff --git a/source3/libsmb/asn1.c b/source3/libsmb/asn1.c index e4c2d3af80..17b1ee1089 100644 --- a/source3/libsmb/asn1.c +++ b/source3/libsmb/asn1.c @@ -30,9 +30,13 @@ void asn1_free(ASN1_DATA *data) /* write to the ASN1 buffer, advancing the buffer pointer */ BOOL asn1_write(ASN1_DATA *data, const void *p, int len) { + if (data->has_error) return False; if (data->length < data->ofs+len) { data->data = Realloc(data->data, data->ofs+len); - if (!data->data) return False; + if (!data->data) { + data->has_error = True; + return False; + } data->length = data->ofs+len; } memcpy(data->data + data->ofs, p, len); @@ -53,13 +57,15 @@ BOOL asn1_push_tag(ASN1_DATA *data, uint8 tag) asn1_write_uint8(data, tag); nesting = (struct nesting *)malloc(sizeof(struct nesting)); - if (!nesting) return False; + if (!nesting) { + data->has_error = True; + return False; + } nesting->start = data->ofs; nesting->next = data->nesting; data->nesting = nesting; - asn1_write_uint8(data, 0xff); - return True; + return asn1_write_uint8(data, 0xff); } /* pop a tag */ @@ -71,6 +77,7 @@ BOOL asn1_pop_tag(ASN1_DATA *data) nesting = data->nesting; if (!nesting) { + data->has_error = True; return False; } len = data->ofs - (nesting->start+1); @@ -79,8 +86,8 @@ BOOL asn1_pop_tag(ASN1_DATA *data) need to correct our mistake */ if (len > 127) { data->data[nesting->start] = 0x82; - asn1_write_uint8(data, 0); - asn1_write_uint8(data, 0); + 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; @@ -99,10 +106,10 @@ BOOL asn1_write_OID(ASN1_DATA *data, const char *OID) unsigned v, v2; char *p = (char *)OID; - asn1_push_tag(data, ASN1_OID); + if (!asn1_push_tag(data, ASN1_OID)) return False; v = strtol(p, &p, 10); v2 = strtol(p, &p, 10); - asn1_write_uint8(data, 40*v + v2); + if (!asn1_write_uint8(data, 40*v + v2)) return False; while (*p) { v = strtol(p, &p, 10); @@ -110,10 +117,9 @@ BOOL asn1_write_OID(ASN1_DATA *data, const char *OID) if (v >= (1<<21)) asn1_write_uint8(data, 0x80 | ((v>>21)&0xff)); if (v >= (1<<14)) asn1_write_uint8(data, 0x80 | ((v>>14)&0xff)); if (v >= (1<<7)) asn1_write_uint8(data, 0x80 | ((v>>7)&0xff)); - asn1_write_uint8(data, v&0x7f); + if (!asn1_write_uint8(data, v&0x7f)) return False; } - asn1_pop_tag(data); - return True; + return asn1_pop_tag(data); } /* write an octet string */ @@ -122,7 +128,7 @@ BOOL asn1_write_OctetString(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 True; + return !data->has_error; } /* write a general string */ @@ -131,7 +137,7 @@ BOOL asn1_write_GeneralString(ASN1_DATA *data, const char *s) asn1_push_tag(data, ASN1_GENERAL_STRING); asn1_write(data, s, strlen(s)); asn1_pop_tag(data); - return True; + return !data->has_error; } /* write a BOOLEAN */ @@ -139,17 +145,20 @@ BOOL asn1_write_BOOLEAN(ASN1_DATA *data, BOOL v) { asn1_write_uint8(data, ASN1_BOOLEAN); asn1_write_uint8(data, v); - return True; + return !data->has_error; } /* load a ASN1_DATA structure with a lump of data, ready to be parsed */ -BOOL asn1_load(ASN1_DATA *data, void *p, size_t length) +BOOL asn1_load(ASN1_DATA *data, DATA_BLOB blob) { ZERO_STRUCTP(data); - data->data = memdup(p, length); - if (!data->data) return False; - data->length = length; + data->data = memdup(blob.data, blob.length); + if (!data->data) { + data->has_error = True; + return False; + } + data->length = blob.length; return True; } @@ -157,6 +166,7 @@ BOOL asn1_load(ASN1_DATA *data, void *p, size_t length) BOOL asn1_read(ASN1_DATA *data, void *p, int len) { if (data->ofs + len > data->length) { + data->has_error = True; return False; } memcpy(p, data->data + data->ofs, len); @@ -164,4 +174,144 @@ BOOL asn1_read(ASN1_DATA *data, void *p, int len) return True; } +/* read a uint8 from a ASN1 buffer */ +BOOL asn1_read_uint8(ASN1_DATA *data, uint8 *v) +{ + return asn1_read(data, v, 1); +} +/* start reading a nested asn1 structure */ +BOOL asn1_start_tag(ASN1_DATA *data, uint8 tag) +{ + uint8 b; + struct nesting *nesting; + + asn1_read_uint8(data, &b); + if (b != tag) { + data->has_error = True; + return False; + } + nesting = (struct nesting *)malloc(sizeof(struct nesting)); + if (!nesting) { + data->has_error = True; + return False; + } + + asn1_read_uint8(data, &b); + if (b & 0x80) { + int n = b & 0x7f; + if (n != 2) { + data->has_error = True; + return False; + } + asn1_read_uint8(data, &b); + nesting->taglen = b<<8; + asn1_read_uint8(data, &b); + nesting->taglen |= b; + } else { + nesting->taglen = b; + } + nesting->start = data->ofs; + nesting->next = data->nesting; + data->nesting = nesting; + return !data->has_error; +} + + +/* stop reading a tag */ +BOOL asn1_end_tag(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; + free(nesting); + return True; +} + +/* work out how many bytes are left in this nested tag */ +int asn1_tag_remaining(ASN1_DATA *data) +{ + if (!data->nesting) { + data->has_error = True; + return -1; + } + return data->nesting->taglen - (data->ofs - data->nesting->start); +} + +/* read an object ID from a ASN1 buffer */ +BOOL asn1_read_OID(ASN1_DATA *data, char **OID) +{ + uint8 b; + pstring oid; + fstring el; + + if (!asn1_start_tag(data, ASN1_OID)) return False; + asn1_read_uint8(data, &b); + + oid[0] = 0; + snprintf(el, sizeof(el), "%u", b/40); + pstrcat(oid, el); + snprintf(el, sizeof(el), " %u", b%40); + pstrcat(oid, el); + + while (asn1_tag_remaining(data) > 0) { + unsigned v = 0; + do { + asn1_read_uint8(data, &b); + v = (v<<7) | (b&0x7f); + } while (!data->has_error && b & 0x80); + snprintf(el, sizeof(el), " %u", v); + pstrcat(oid, el); + } + + asn1_end_tag(data); + + *OID = strdup(oid); + + return !data->has_error; +} + +/* check that the next object ID is correct */ +BOOL asn1_check_OID(ASN1_DATA *data, char *OID) +{ + char *id; + + if (!asn1_read_OID(data, &id)) return False; + + if (strcmp(id, OID) != 0) { + data->has_error = True; + return False; + } + free(id); + return True; +} + +/* read a GeneralString from a ASN1 buffer */ +BOOL asn1_read_GeneralString(ASN1_DATA *data, char **s) +{ + int len; + if (!asn1_start_tag(data, ASN1_GENERAL_STRING)) return False; + len = asn1_tag_remaining(data); + *s = malloc(len+1); + if (! *s) { + data->has_error = True; + return False; + } + asn1_read(data, *s, len); + (*s)[len] = 0; + asn1_end_tag(data); + return !data->has_error; +} |