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-rw-r--r--src/pluto/asn1.c770
1 files changed, 770 insertions, 0 deletions
diff --git a/src/pluto/asn1.c b/src/pluto/asn1.c
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--- /dev/null
+++ b/src/pluto/asn1.c
@@ -0,0 +1,770 @@
+/* Simple ASN.1 parser
+ * Copyright (C) 2000-2004 Andreas Steffen, Zuercher Hochschule Winterthur
+ *
+ * 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 2 of the License, or (at your
+ * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ *
+ * RCSID $Id: asn1.c,v 1.16 2006/01/04 21:00:43 as Exp $
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include <freeswan.h>
+
+#include "constants.h"
+#include "defs.h"
+#include "mp_defs.h"
+#include "asn1.h"
+#include "oid.h"
+#include "log.h"
+
+/* some common prefabricated ASN.1 constants */
+
+static u_char ASN1_INTEGER_0_str[] = { 0x02, 0x00 };
+static u_char ASN1_INTEGER_1_str[] = { 0x02, 0x01, 0x01 };
+static u_char ASN1_INTEGER_2_str[] = { 0x02, 0x01, 0x02 };
+
+const chunk_t ASN1_INTEGER_0 = strchunk(ASN1_INTEGER_0_str);
+const chunk_t ASN1_INTEGER_1 = strchunk(ASN1_INTEGER_1_str);
+const chunk_t ASN1_INTEGER_2 = strchunk(ASN1_INTEGER_2_str);
+
+/* some popular algorithmIdentifiers */
+
+static u_char ASN1_md5_id_str[] = {
+ 0x30, 0x0C,
+ 0x06, 0x08, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05,
+ 0x05, 0x00
+};
+
+static u_char ASN1_sha1_id_str[] = {
+ 0x30, 0x09,
+ 0x06, 0x05, 0x2B, 0x0E,0x03, 0x02, 0x1A,
+ 0x05, 0x00
+};
+
+static u_char ASN1_md5WithRSA_id_str[] = {
+ 0x30, 0x0D,
+ 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x04,
+ 0x05, 0x00
+};
+
+static u_char ASN1_sha1WithRSA_id_str[] = {
+ 0x30, 0x0D,
+ 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x05,
+ 0x05, 0x00
+};
+
+static u_char ASN1_rsaEncryption_id_str[] = {
+ 0x30, 0x0D,
+ 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01,
+ 0x05, 0x00
+};
+
+const chunk_t ASN1_md5_id = strchunk(ASN1_md5_id_str);
+const chunk_t ASN1_sha1_id = strchunk(ASN1_sha1_id_str);
+const chunk_t ASN1_rsaEncryption_id = strchunk(ASN1_rsaEncryption_id_str);
+const chunk_t ASN1_md5WithRSA_id = strchunk(ASN1_md5WithRSA_id_str);
+const chunk_t ASN1_sha1WithRSA_id = strchunk(ASN1_sha1WithRSA_id_str);
+
+/* ASN.1 definiton of an algorithmIdentifier */
+
+static const asn1Object_t algorithmIdentifierObjects[] = {
+ { 0, "algorithmIdentifier", ASN1_SEQUENCE, ASN1_NONE }, /* 0 */
+ { 1, "algorithm", ASN1_OID, ASN1_BODY }, /* 1 */
+ { 1, "parameters", ASN1_EOC, ASN1_RAW } /* 2 */
+};
+
+#define ALGORITHM_ID_ALG 1
+#define ALGORITHM_ID_PARAMETERS 2
+#define ALGORITHM_ID_ROOF 3
+
+/*
+ * return the ASN.1 encoded algorithm identifier
+ */
+chunk_t
+asn1_algorithmIdentifier(int oid)
+{
+ switch (oid)
+ {
+ case OID_RSA_ENCRYPTION:
+ return ASN1_rsaEncryption_id;
+ case OID_MD5_WITH_RSA:
+ return ASN1_md5WithRSA_id;
+ case OID_SHA1_WITH_RSA:
+ return ASN1_sha1WithRSA_id;
+ case OID_MD5:
+ return ASN1_md5_id;
+ case OID_SHA1:
+ return ASN1_sha1_id;
+ default:
+ return empty_chunk;
+ }
+}
+
+/* If the oid is listed in the oid_names table then the corresponding
+ * position in the oid_names table is returned otherwise -1 is returned
+ */
+int
+known_oid(chunk_t object)
+{
+ int oid = 0;
+
+ while (object.len)
+ {
+ if (oid_names[oid].octet == *object.ptr)
+ {
+ if (--object.len == 0 || oid_names[oid].down == 0)
+ {
+ return oid; /* found terminal symbol */
+ }
+ else
+ {
+ object.ptr++; oid++; /* advance to next hex octet */
+ }
+ }
+ else
+ {
+ if (oid_names[oid].next)
+ oid = oid_names[oid].next;
+ else
+ return OID_UNKNOWN;
+ }
+ }
+ return -1;
+}
+
+/*
+ * Decodes the length in bytes of an ASN.1 object
+ */
+u_int
+asn1_length(chunk_t *blob)
+{
+ u_char n;
+ size_t len;
+
+ /* advance from tag field on to length field */
+ blob->ptr++;
+ blob->len--;
+
+ /* read first octet of length field */
+ n = *blob->ptr++;
+ blob->len--;
+
+ if ((n & 0x80) == 0) /* single length octet */
+ return n;
+
+ /* composite length, determine number of length octets */
+ n &= 0x7f;
+
+ if (n > blob->len)
+ {
+ DBG(DBG_PARSING,
+ DBG_log("number of length octets is larger than ASN.1 object")
+ )
+ return ASN1_INVALID_LENGTH;
+ }
+
+ if (n > sizeof(len))
+ {
+ DBG(DBG_PARSING,
+ DBG_log("number of length octets is larger than limit of %d octets"
+ , (int)sizeof(len))
+ )
+ return ASN1_INVALID_LENGTH;
+ }
+
+ len = 0;
+
+ while (n-- > 0)
+ {
+ len = 256*len + *blob->ptr++;
+ blob->len--;
+ }
+ return len;
+}
+
+/*
+ * codes ASN.1 lengths up to a size of 16'777'215 bytes
+ */
+void
+code_asn1_length(size_t length, chunk_t *code)
+{
+ if (length < 128)
+ {
+ code->ptr[0] = length;
+ code->len = 1;
+ }
+ else if (length < 256)
+ {
+ code->ptr[0] = 0x81;
+ code->ptr[1] = (u_char) length;
+ code->len = 2;
+ }
+ else if (length < 65536)
+ {
+ code->ptr[0] = 0x82;
+ code->ptr[1] = length >> 8;
+ code->ptr[2] = length & 0x00ff;
+ code->len = 3;
+ }
+ else
+ {
+ code->ptr[0] = 0x83;
+ code->ptr[1] = length >> 16;
+ code->ptr[2] = (length >> 8) & 0x00ff;
+ code->ptr[3] = length & 0x0000ff;
+ code->len = 4;
+ }
+}
+
+/*
+ * build an empty asn.1 object with tag and length fields already filled in
+ */
+u_char*
+build_asn1_object(chunk_t *object, asn1_t type, size_t datalen)
+{
+ u_char length_buf[4];
+ chunk_t length = { length_buf, 0 };
+ u_char *pos;
+
+ /* code the asn.1 length field */
+ code_asn1_length(datalen, &length);
+
+ /* allocate memory for the asn.1 TLV object */
+ object->len = 1 + length.len + datalen;
+ object->ptr = alloc_bytes(object->len, "asn1 object");
+
+ /* set position pointer at the start of the object */
+ pos = object->ptr;
+
+ /* copy the asn.1 tag field and advance the pointer */
+ *pos++ = type;
+
+ /* copy the asn.1 length field and advance the pointer */
+ chunkcpy(pos, length);
+
+ return pos;
+}
+
+/*
+ * build a simple ASN.1 object
+ */
+chunk_t
+asn1_simple_object(asn1_t tag, chunk_t content)
+{
+ chunk_t object;
+
+ u_char *pos = build_asn1_object(&object, tag, content.len);
+ chunkcpy(pos, content);
+
+ return object;
+}
+
+/* Build an ASN.1 object from a variable number of individual chunks.
+ * Depending on the mode, chunks either are moved ('m') or copied ('c').
+ */
+chunk_t
+asn1_wrap(asn1_t type, const char *mode, ...)
+{
+ chunk_t construct;
+ va_list chunks;
+ u_char *pos;
+ int i;
+ int count = strlen(mode);
+
+ /* sum up lengths of individual chunks */
+ va_start(chunks, mode);
+ construct.len = 0;
+ for (i = 0; i < count; i++)
+ {
+ chunk_t ch = va_arg(chunks, chunk_t);
+ construct.len += ch.len;
+ }
+ va_end(chunks);
+
+ /* allocate needed memory for construct */
+ pos = build_asn1_object(&construct, type, construct.len);
+
+ /* copy or move the chunks */
+ va_start(chunks, mode);
+ for (i = 0; i < count; i++)
+ {
+ chunk_t ch = va_arg(chunks, chunk_t);
+
+ switch (*mode++)
+ {
+ case 'm':
+ mv_chunk(&pos, ch);
+ break;
+ case 'c':
+ default:
+ chunkcpy(pos, ch);
+ }
+ }
+ va_end(chunks);
+
+ return construct;
+}
+
+/*
+ * convert a MP integer into a DER coded ASN.1 object
+ */
+chunk_t
+asn1_integer_from_mpz(const mpz_t value)
+{
+ size_t bits = mpz_sizeinbase(value, 2); /* size in bits */
+ size_t size = 1 + bits / BITS_PER_BYTE; /* size in bytes */
+ chunk_t n = mpz_to_n(value, size);
+
+ return asn1_wrap(ASN1_INTEGER, "m", n);
+}
+
+/*
+ * determines if a character string is of type ASN.1 printableString
+ */
+bool
+is_printablestring(chunk_t str)
+{
+ const char printablestring_charset[] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 '()+,-./:=?";
+ u_int i;
+
+ for (i = 0; i < str.len; i++)
+ {
+ if (strchr(printablestring_charset, str.ptr[i]) == NULL)
+ return FALSE;
+ }
+ return TRUE;
+}
+
+/*
+ * Converts ASN.1 UTCTIME or GENERALIZEDTIME into calender time
+ */
+time_t
+asn1totime(const chunk_t *utctime, asn1_t type)
+{
+ struct tm t;
+ time_t tz_offset;
+ u_char *eot = NULL;
+
+ if ((eot = memchr(utctime->ptr, 'Z', utctime->len)) != NULL)
+ {
+ tz_offset = 0; /* Zulu time with a zero time zone offset */
+ }
+ else if ((eot = memchr(utctime->ptr, '+', utctime->len)) != NULL)
+ {
+ int tz_hour, tz_min;
+
+ sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
+ tz_offset = 3600*tz_hour + 60*tz_min; /* positive time zone offset */
+ }
+ else if ((eot = memchr(utctime->ptr, '-', utctime->len)) != NULL)
+ {
+ int tz_hour, tz_min;
+
+ sscanf(eot+1, "%2d%2d", &tz_hour, &tz_min);
+ tz_offset = -3600*tz_hour - 60*tz_min; /* negative time zone offset */
+ }
+ else
+ {
+ return 0; /* error in time format */
+ }
+
+ {
+ const char* format = (type == ASN1_UTCTIME)? "%2d%2d%2d%2d%2d":
+ "%4d%2d%2d%2d%2d";
+
+ sscanf(utctime->ptr, format, &t.tm_year, &t.tm_mon, &t.tm_mday,
+ &t.tm_hour, &t.tm_min);
+ }
+
+ /* is there a seconds field? */
+ if ((eot - utctime->ptr) == ((type == ASN1_UTCTIME)?12:14))
+ {
+ sscanf(eot-2, "%2d", &t.tm_sec);
+ }
+ else
+ {
+ t.tm_sec = 0;
+ }
+
+ /* representation of year */
+ if (t.tm_year >= 1900)
+ {
+ t.tm_year -= 1900;
+ }
+ else if (t.tm_year >= 100)
+ {
+ return 0;
+ }
+ else if (t.tm_year < 50)
+ {
+ t.tm_year += 100;
+ }
+
+ /* representation of month 0..11*/
+ t.tm_mon--;
+
+ /* set daylight saving time to off */
+ t.tm_isdst = 0;
+
+ /* compensate timezone */
+
+ return mktime(&t) - timezone - tz_offset;
+}
+
+/*
+ * convert a date into ASN.1 UTCTIME or GENERALIZEDTIME format
+ */
+chunk_t
+timetoasn1(const time_t *time, asn1_t type)
+{
+ int offset;
+ const char *format;
+ char buf[TIMETOA_BUF];
+ chunk_t formatted_time;
+ struct tm *t = gmtime(time);
+
+ if (type == ASN1_GENERALIZEDTIME)
+ {
+ format = "%04d%02d%02d%02d%02d%02dZ";
+ offset = 1900;
+ }
+ else /* ASN1_UTCTIME */
+ {
+ format = "%02d%02d%02d%02d%02d%02dZ";
+ offset = (t->tm_year < 100)? 0 : -100;
+ }
+ sprintf(buf, format, t->tm_year + offset, t->tm_mon + 1, t->tm_mday
+ , t->tm_hour, t->tm_min, t->tm_sec);
+ formatted_time.ptr = buf;
+ formatted_time.len = strlen(buf);
+ return asn1_simple_object(type, formatted_time);
+}
+
+
+/*
+ * Initializes the internal context of the ASN.1 parser
+ */
+void
+asn1_init(asn1_ctx_t *ctx, chunk_t blob, u_int level0,
+ bool implicit, u_int cond)
+{
+ ctx->blobs[0] = blob;
+ ctx->level0 = level0;
+ ctx->implicit = implicit;
+ ctx->cond = cond;
+ memset(ctx->loopAddr, '\0', sizeof(ctx->loopAddr));
+}
+
+/*
+ * print the value of an ASN.1 simple object
+ */
+static void
+debug_asn1_simple_object(chunk_t object, asn1_t type, u_int cond)
+{
+ int oid;
+
+ switch (type)
+ {
+ case ASN1_OID:
+ oid = known_oid(object);
+ if (oid != OID_UNKNOWN)
+ {
+ DBG(DBG_PARSING,
+ DBG_log(" '%s'",oid_names[oid].name);
+ )
+ return;
+ }
+ break;
+ case ASN1_UTF8STRING:
+ case ASN1_IA5STRING:
+ case ASN1_PRINTABLESTRING:
+ case ASN1_T61STRING:
+ case ASN1_VISIBLESTRING:
+ DBG(DBG_PARSING,
+ DBG_log(" '%.*s'", (int)object.len, object.ptr);
+ )
+ return;
+ case ASN1_UTCTIME:
+ case ASN1_GENERALIZEDTIME:
+ DBG(DBG_PARSING,
+ time_t time = asn1totime(&object, type);
+ DBG_log(" '%s'", timetoa(&time, TRUE));
+ )
+ return;
+ default:
+ break;
+ }
+ DBG(cond,
+ DBG_dump_chunk("", object);
+ )
+}
+
+/*
+ * Parses and extracts the next ASN.1 object
+ */
+bool
+extract_object(asn1Object_t const *objects,
+ u_int *objectID, chunk_t *object, u_int *level, asn1_ctx_t *ctx)
+{
+ asn1Object_t obj = objects[*objectID];
+ chunk_t *blob;
+ chunk_t *blob1;
+ u_char *start_ptr;
+
+ *object = empty_chunk;
+
+ if (obj.flags & ASN1_END) /* end of loop or option found */
+ {
+ if (ctx->loopAddr[obj.level] && ctx->blobs[obj.level+1].len > 0)
+ {
+ *objectID = ctx->loopAddr[obj.level]; /* another iteration */
+ obj = objects[*objectID];
+ }
+ else
+ {
+ ctx->loopAddr[obj.level] = 0; /* exit loop or option*/
+ return TRUE;
+ }
+ }
+
+ *level = ctx->level0 + obj.level;
+ blob = ctx->blobs + obj.level;
+ blob1 = blob + 1;
+ start_ptr = blob->ptr;
+
+ /* handle ASN.1 defaults values */
+
+ if ((obj.flags & ASN1_DEF)
+ && (blob->len == 0 || *start_ptr != obj.type) )
+ {
+ /* field is missing */
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s:", *level, obj.name);
+ )
+ if (obj.type & ASN1_CONSTRUCTED)
+ {
+ (*objectID)++ ; /* skip context-specific tag */
+ }
+ return TRUE;
+ }
+
+ /* handle ASN.1 options */
+
+ if ((obj.flags & ASN1_OPT)
+ && (blob->len == 0 || *start_ptr != obj.type))
+ {
+ /* advance to end of missing option field */
+ do
+ (*objectID)++;
+ while (!((objects[*objectID].flags & ASN1_END)
+ && (objects[*objectID].level == obj.level)));
+ return TRUE;
+ }
+
+ /* an ASN.1 object must possess at least a tag and length field */
+
+ if (blob->len < 2)
+ {
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s: ASN.1 object smaller than 2 octets",
+ *level, obj.name);
+ )
+ return FALSE;
+ }
+
+ blob1->len = asn1_length(blob);
+
+ if (blob1->len == ASN1_INVALID_LENGTH || blob->len < blob1->len)
+ {
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s: length of ASN.1 object invalid or too large",
+ *level, obj.name);
+ )
+ return FALSE;
+ }
+
+ blob1->ptr = blob->ptr;
+ blob->ptr += blob1->len;
+ blob->len -= blob1->len;
+
+ /* return raw ASN.1 object without prior type checking */
+
+ if (obj.flags & ASN1_RAW)
+ {
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s:", *level, obj.name);
+ )
+ object->ptr = start_ptr;
+ object->len = (size_t)(blob->ptr - start_ptr);
+ return TRUE;
+ }
+
+ if (*start_ptr != obj.type && !(ctx->implicit && *objectID == 0))
+ {
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s: ASN1 tag 0x%02x expected, but is 0x%02x",
+ *level, obj.name, obj.type, *start_ptr);
+ DBG_dump("", start_ptr, (u_int)(blob->ptr - start_ptr));
+ )
+ return FALSE;
+ }
+
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s:", ctx->level0+obj.level, obj.name);
+ )
+
+ /* In case of "SEQUENCE OF" or "SET OF" start a loop */
+
+ if (obj.flags & ASN1_LOOP)
+ {
+ if (blob1->len > 0)
+ {
+ /* at least one item, start the loop */
+ ctx->loopAddr[obj.level] = *objectID + 1;
+ }
+ else
+ {
+ /* no items, advance directly to end of loop */
+ do
+ (*objectID)++;
+ while (!((objects[*objectID].flags & ASN1_END)
+ && (objects[*objectID].level == obj.level)));
+ return TRUE;
+ }
+ }
+
+ if (obj.flags & ASN1_OBJ)
+ {
+ object->ptr = start_ptr;
+ object->len = (size_t)(blob->ptr - start_ptr);
+ DBG(ctx->cond,
+ DBG_dump_chunk("", *object);
+ )
+ }
+ else if (obj.flags & ASN1_BODY)
+ {
+ *object = *blob1;
+ debug_asn1_simple_object(*object, obj.type, ctx->cond);
+ }
+ return TRUE;
+}
+
+/*
+ * parse an ASN.1 simple type
+ */
+bool
+parse_asn1_simple_object(chunk_t *object, asn1_t type, u_int level
+, const char* name)
+{
+ size_t len;
+
+ /* an ASN.1 object must possess at least a tag and length field */
+ if (object->len < 2)
+ {
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s: ASN.1 object smaller than 2 octets",
+ level, name);
+ )
+ return FALSE;
+ }
+
+ if (*object->ptr != type)
+ {
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s: ASN1 tag 0x%02x expected, but is 0x%02x",
+ level, name, type, *object->ptr);
+ )
+ return FALSE;
+ }
+
+ len = asn1_length(object);
+
+ if (len == ASN1_INVALID_LENGTH || object->len < len)
+ {
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s: length of ASN.1 object invalid or too large",
+ level, name);
+ )
+ return FALSE;
+ }
+
+ DBG(DBG_PARSING,
+ DBG_log("L%d - %s:", level, name);
+ )
+ debug_asn1_simple_object(*object, type, DBG_RAW);
+ return TRUE;
+}
+
+/*
+ * extracts an algorithmIdentifier
+ */
+int
+parse_algorithmIdentifier(chunk_t blob, int level0, chunk_t *parameters)
+{
+ asn1_ctx_t ctx;
+ chunk_t object;
+ u_int level;
+ int alg = OID_UNKNOWN;
+ int objectID = 0;
+
+ asn1_init(&ctx, blob, level0, FALSE, DBG_RAW);
+
+ while (objectID < ALGORITHM_ID_ROOF)
+ {
+ if (!extract_object(algorithmIdentifierObjects, &objectID, &object, &level, &ctx))
+ return OID_UNKNOWN;
+
+ switch (objectID)
+ {
+ case ALGORITHM_ID_ALG:
+ alg = known_oid(object);
+ break;
+ case ALGORITHM_ID_PARAMETERS:
+ if (parameters != NULL)
+ *parameters = object;
+ break;
+ default:
+ break;
+ }
+ objectID++;
+ }
+ return alg;
+ }
+
+/*
+ * tests if a blob contains a valid ASN.1 set or sequence
+ */
+bool
+is_asn1(chunk_t blob)
+{
+ u_int len;
+ u_char tag = *blob.ptr;
+
+ if (tag != ASN1_SEQUENCE && tag != ASN1_SET)
+ {
+ DBG(DBG_PARSING,
+ DBG_log(" file content is not binary ASN.1");
+ )
+ return FALSE;
+ }
+ len = asn1_length(&blob);
+ if (len != blob.len)
+ {
+ DBG(DBG_PARSING,
+ DBG_log(" file size does not match ASN.1 coded length");
+ )
+ return FALSE;
+ }
+ return TRUE;
+}
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