Constify d2i, s2i, c2i and r2i functions and other associated
[openssl.git] / crypto / asn1 / a_int.c
index df79cf99bbbcdf546e401947d96bdd26d343e91d..5d76de79ba89d3e8ab3b8b3b8b8c4476ea5e1354 100644 (file)
 
 #include <stdio.h>
 #include "cryptlib.h"
-#include "asn1.h"
+#include <openssl/asn1.h>
 
-/* ASN1err(ASN1_F_D2I_ASN1_INTEGER,ASN1_R_EXPECTING_AN_INTEGER);
+ASN1_INTEGER *ASN1_INTEGER_dup(ASN1_INTEGER *x)
+{ return M_ASN1_INTEGER_dup(x);}
+
+int ASN1_INTEGER_cmp(ASN1_INTEGER *x, ASN1_INTEGER *y)
+{ return M_ASN1_INTEGER_cmp(x,y);}
+
+/* 
+ * This converts an ASN1 INTEGER into its content encoding.
+ * The internal representation is an ASN1_STRING whose data is a big endian
+ * representation of the value, ignoring the sign. The sign is determined by
+ * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative. 
+ *
+ * Positive integers are no problem: they are almost the same as the DER
+ * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
+ *
+ * Negative integers are a bit trickier...
+ * The DER representation of negative integers is in 2s complement form.
+ * The internal form is converted by complementing each octet and finally 
+ * adding one to the result. This can be done less messily with a little trick.
+ * If the internal form has trailing zeroes then they will become FF by the
+ * complement and 0 by the add one (due to carry) so just copy as many trailing 
+ * zeros to the destination as there are in the source. The carry will add one
+ * to the last none zero octet: so complement this octet and add one and finally
+ * complement any left over until you get to the start of the string.
+ *
+ * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
+ * with 0xff. However if the first byte is 0x80 and one of the following bytes
+ * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
+ * followed by optional zeros isn't padded.
  */
 
-int i2d_ASN1_INTEGER(a,pp)
-ASN1_INTEGER *a;
-unsigned char **pp;
+int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
        {
-       int pad=0,ret,r,i,t;
-       unsigned char *p,*pt,*n,pb=0;
+       int pad=0,ret,i,neg;
+       unsigned char *p,*n,pb=0;
 
        if ((a == NULL) || (a->data == NULL)) return(0);
-       t=a->type;
+       neg=a->type & V_ASN1_NEG;
        if (a->length == 0)
                ret=1;
        else
                {
                ret=a->length;
                i=a->data[0];
-               if ((t == V_ASN1_INTEGER) && (i > 127))
-                       {
+               if (!neg && (i > 127)) {
                        pad=1;
                        pb=0;
+               } else if(neg) {
+                       if(i>128) {
+                               pad=1;
+                               pb=0xFF;
+                       } else if(i == 128) {
+                       /*
+                        * Special case: if any other bytes non zero we pad:
+                        * otherwise we don't.
+                        */
+                               for(i = 1; i < a->length; i++) if(a->data[i]) {
+                                               pad=1;
+                                               pb=0xFF;
+                                               break;
+                               }
                        }
-               else if ((t == V_ASN1_NEG_INTEGER) && (i>128))
-                       {
-                       pad=1;
-                       pb=0xFF;
-                       }
+               }
                ret+=pad;
                }
-       r=ASN1_object_size(0,ret,V_ASN1_INTEGER);
-       if (pp == NULL) return(r);
+       if (pp == NULL) return(ret);
        p= *pp;
 
-       ASN1_put_object(&p,0,ret,V_ASN1_INTEGER,V_ASN1_UNIVERSAL);
        if (pad) *(p++)=pb;
-       if (a->length == 0)
-               *(p++)=0;
-       else if (t == V_ASN1_INTEGER)
+       if (a->length == 0) *(p++)=0;
+       else if (!neg) memcpy(p,a->data,(unsigned int)a->length);
+       else {
+               /* Begin at the end of the encoding */
+               n=a->data + a->length - 1;
+               p += a->length - 1;
+               i = a->length;
+               /* Copy zeros to destination as long as source is zero */
+               while(!*n) {
+                       *(p--) = 0;
+                       n--;
+                       i--;
+               }
+               /* Complement and increment next octet */
+               *(p--) = ((*(n--)) ^ 0xff) + 1;
+               i--;
+               /* Complement any octets left */
+               for(;i > 0; i--) *(p--) = *(n--) ^ 0xff;
+       }
+
+       *pp+=ret;
+       return(ret);
+       }
+
+/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
+
+ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
+            long len)
+       {
+       ASN1_INTEGER *ret=NULL;
+       const unsigned char *p, *pend;
+       unsigned char *to,*s;
+       int i;
+
+       if ((a == NULL) || ((*a) == NULL))
                {
-               memcpy(p,a->data,(unsigned int)a->length);
-               p+=a->length;
+               if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
+               ret->type=V_ASN1_INTEGER;
                }
        else
+               ret=(*a);
+
+       p= *pp;
+       pend = p + len;
+
+       /* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
+        * signifies a missing NULL parameter. */
+       s=(unsigned char *)OPENSSL_malloc((int)len+1);
+       if (s == NULL)
                {
-               n=a->data;
-               pt=p;
-               for (i=a->length; i>0; i--)
-                       *(p++)= (*(n++)^0xFF)+1;
-               if (!pad) *pt|=0x80;
+               i=ERR_R_MALLOC_FAILURE;
+               goto err;
                }
+       to=s;
+       if(!len) {
+               /* Strictly speaking this is an illegal INTEGER but we
+                * tolerate it.
+                */
+               ret->type=V_ASN1_INTEGER;
+       } else if (*p & 0x80) /* a negative number */
+               {
+               ret->type=V_ASN1_NEG_INTEGER;
+               if ((*p == 0xff) && (len != 1)) {
+                       p++;
+                       len--;
+               }
+               i = len;
+               p += i - 1;
+               to += i - 1;
+               while((!*p) && i) {
+                       *(to--) = 0;
+                       i--;
+                       p--;
+               }
+               /* Special case: if all zeros then the number will be of
+                * the form FF followed by n zero bytes: this corresponds to
+                * 1 followed by n zero bytes. We've already written n zeros
+                * so we just append an extra one and set the first byte to
+                * a 1. This is treated separately because it is the only case
+                * where the number of bytes is larger than len.
+                */
+               if(!i) {
+                       *s = 1;
+                       s[len] = 0;
+                       len++;
+               } else {
+                       *(to--) = (*(p--) ^ 0xff) + 1;
+                       i--;
+                       for(;i > 0; i--) *(to--) = *(p--) ^ 0xff;
+               }
+       } else {
+               ret->type=V_ASN1_INTEGER;
+               if ((*p == 0) && (len != 1))
+                       {
+                       p++;
+                       len--;
+                       }
+               memcpy(s,p,(int)len);
+       }
 
-       *pp=p;
-       return(r);
+       if (ret->data != NULL) OPENSSL_free(ret->data);
+       ret->data=s;
+       ret->length=(int)len;
+       if (a != NULL) (*a)=ret;
+       *pp=pend;
+       return(ret);
+err:
+       ASN1err(ASN1_F_D2I_ASN1_INTEGER,i);
+       if ((ret != NULL) && ((a == NULL) || (*a != ret)))
+               M_ASN1_INTEGER_free(ret);
+       return(NULL);
        }
 
-ASN1_INTEGER *d2i_ASN1_INTEGER(a, pp, length)
-ASN1_INTEGER **a;
-unsigned char **pp;
-long length;
+
+/* This is a version of d2i_ASN1_INTEGER that ignores the sign bit of
+ * ASN1 integers: some broken software can encode a positive INTEGER
+ * with its MSB set as negative (it doesn't add a padding zero).
+ */
+
+ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
+            long length)
        {
        ASN1_INTEGER *ret=NULL;
-       unsigned char *p,*to,*s;
+       const unsigned char *p;
+       unsigned char *to,*s;
        long len;
        int inf,tag,xclass;
        int i;
 
        if ((a == NULL) || ((*a) == NULL))
                {
-               if ((ret=ASN1_INTEGER_new()) == NULL) return(NULL);
+               if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
                ret->type=V_ASN1_INTEGER;
                }
        else
@@ -149,29 +280,17 @@ long length;
                goto err;
                }
 
-       /* We must Malloc stuff, even for 0 bytes otherwise it
+       /* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
         * signifies a missing NULL parameter. */
-       s=(unsigned char *)Malloc((int)len+1);
+       s=(unsigned char *)OPENSSL_malloc((int)len+1);
        if (s == NULL)
                {
                i=ERR_R_MALLOC_FAILURE;
                goto err;
                }
        to=s;
-       if (*p & 0x80) /* a negative number */
-               {
-               ret->type=V_ASN1_NEG_INTEGER;
-               if (*p == 0xff)
-                       {
-                       p++;
-                       len--;
-                       }
-               for (i=(int)len; i>0; i--)
-                       *(to++)= (*(p++)^0xFF)+1;
-               }
-       else
-               {
-               ret->type=V_ASN1_INTEGER;
+       ret->type=V_ASN1_INTEGER;
+       if(len) {
                if ((*p == 0) && (len != 1))
                        {
                        p++;
@@ -179,35 +298,34 @@ long length;
                        }
                memcpy(s,p,(int)len);
                p+=len;
-               }
+       }
 
-       if (ret->data != NULL) Free((char *)ret->data);
+       if (ret->data != NULL) OPENSSL_free(ret->data);
        ret->data=s;
        ret->length=(int)len;
        if (a != NULL) (*a)=ret;
        *pp=p;
        return(ret);
 err:
-       ASN1err(ASN1_F_D2I_ASN1_INTEGER,i);
+       ASN1err(ASN1_F_D2I_ASN1_UINTEGER,i);
        if ((ret != NULL) && ((a == NULL) || (*a != ret)))
-               ASN1_INTEGER_free(ret);
+               M_ASN1_INTEGER_free(ret);
        return(NULL);
        }
 
-int ASN1_INTEGER_set(a,v)
-ASN1_INTEGER *a;
-long v;
+int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
        {
-       int i,j,k;
+       int j,k;
+       unsigned int i;
        unsigned char buf[sizeof(long)+1];
        long d;
 
        a->type=V_ASN1_INTEGER;
-       if (a->length < (sizeof(long)+1))
+       if (a->length < (int)(sizeof(long)+1))
                {
                if (a->data != NULL)
-                       Free((char *)a->data);
-               if ((a->data=(unsigned char *)Malloc(sizeof(long)+1)) != NULL)
+                       OPENSSL_free(a->data);
+               if ((a->data=(unsigned char *)OPENSSL_malloc(sizeof(long)+1)) != NULL)
                        memset((char *)a->data,0,sizeof(long)+1);
                }
        if (a->data == NULL)
@@ -229,15 +347,13 @@ long v;
                d>>=8;
                }
        j=0;
-       if (v < 0) a->data[j++]=0;
        for (k=i-1; k >=0; k--)
                a->data[j++]=buf[k];
        a->length=j;
        return(1);
        }
 
-long ASN1_INTEGER_get(a)
-ASN1_INTEGER *a;
+long ASN1_INTEGER_get(ASN1_INTEGER *a)
        {
        int neg=0,i;
        long r=0;
@@ -247,15 +363,15 @@ ASN1_INTEGER *a;
        if (i == V_ASN1_NEG_INTEGER)
                neg=1;
        else if (i != V_ASN1_INTEGER)
-               return(0);
+               return -1;
        
-       if (a->length > sizeof(long))
+       if (a->length > (int)sizeof(long))
                {
                /* hmm... a bit ugly */
                return(0xffffffffL);
                }
        if (a->data == NULL)
-               return(0);
+               return 0;
 
        for (i=0; i<a->length; i++)
                {
@@ -266,40 +382,58 @@ ASN1_INTEGER *a;
        return(r);
        }
 
-ASN1_INTEGER *BN_to_ASN1_INTEGER(bn,ai)
-BIGNUM *bn;
-ASN1_INTEGER *ai;
+ASN1_INTEGER *BN_to_ASN1_INTEGER(BIGNUM *bn, ASN1_INTEGER *ai)
        {
        ASN1_INTEGER *ret;
        int len,j;
 
        if (ai == NULL)
-               ret=ASN1_INTEGER_new();
+               ret=M_ASN1_INTEGER_new();
        else
                ret=ai;
        if (ret == NULL)
                {
-               ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ASN1_R_ERROR_STACK);
+               ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_NESTED_ASN1_ERROR);
                goto err;
                }
-       ret->type=V_ASN1_INTEGER;
+       if (BN_get_sign(bn))
+               ret->type = V_ASN1_NEG_INTEGER;
+       else ret->type=V_ASN1_INTEGER;
        j=BN_num_bits(bn);
        len=((j == 0)?0:((j/8)+1));
-       ret->data=(unsigned char *)Malloc(len+4);
+       if (ret->length < len+4)
+               {
+               unsigned char *new_data=OPENSSL_realloc(ret->data, len+4);
+               if (!new_data)
+                       {
+                       ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_MALLOC_FAILURE);
+                       goto err;
+                       }
+               ret->data=new_data;
+               }
        ret->length=BN_bn2bin(bn,ret->data);
+       /* Correct zero case */
+       if(!ret->length)
+               {
+               ret->data[0] = 0;
+               ret->length = 1;
+               }
        return(ret);
 err:
-       if (ret != ai) ASN1_INTEGER_free(ret);
+       if (ret != ai) M_ASN1_INTEGER_free(ret);
        return(NULL);
        }
 
-BIGNUM *ASN1_INTEGER_to_BN(ai,bn)
-ASN1_INTEGER *ai;
-BIGNUM *bn;
+BIGNUM *ASN1_INTEGER_to_BN(ASN1_INTEGER *ai, BIGNUM *bn)
        {
        BIGNUM *ret;
 
        if ((ret=BN_bin2bn(ai->data,ai->length,bn)) == NULL)
                ASN1err(ASN1_F_ASN1_INTEGER_TO_BN,ASN1_R_BN_LIB);
+       else if(ai->type == V_ASN1_NEG_INTEGER)
+               BN_set_sign(ret, 1);
        return(ret);
        }
+
+IMPLEMENT_STACK_OF(ASN1_INTEGER)
+IMPLEMENT_ASN1_SET_OF(ASN1_INTEGER)