--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/asn1/der/sequence/der_decode_sequence_flexi.c	Sun Sep 14 06:47:51 2008 +0000
@@ -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, [email protected], 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 $ */