1 files changed, 389 insertions, 182 deletions

diff --git a/src/lib/libcrypto/bn/bn_lib.c b/src/lib/libcrypto/bn/bn_lib.c
index bfe7628ad4..a016cb7f53 100644
--- a/src/lib/libcrypto/bn/bn_lib.c
+++ b/src/lib/libcrypto/bn/bn_lib.c
@@ -56,13 +56,79 @@
  * [including the GNU Public Licence.]
  */
 
+#ifndef BN_DEBUG
+# undef NDEBUG /* avoid conflicting definitions */
+# define NDEBUG
+#endif
+
+#include <assert.h>
+#include <limits.h>
 #include <stdio.h>
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-char *BN_version="Big Number part of SSLeay 0.9.0b 29-Jun-1998";
+const char *BN_version="Big Number" OPENSSL_VERSION_PTEXT;
 
-BIGNUM *BN_value_one()
+/* For a 32 bit machine
+ * 2 -   4 ==  128
+ * 3 -   8 ==  256
+ * 4 -  16 ==  512
+ * 5 -  32 == 1024
+ * 6 -  64 == 2048
+ * 7 - 128 == 4096
+ * 8 - 256 == 8192
+ */
+static int bn_limit_bits=0;
+static int bn_limit_num=8;        /* (1<<bn_limit_bits) */
+static int bn_limit_bits_low=0;
+static int bn_limit_num_low=8;    /* (1<<bn_limit_bits_low) */
+static int bn_limit_bits_high=0;
+static int bn_limit_num_high=8;   /* (1<<bn_limit_bits_high) */
+static int bn_limit_bits_mont=0;
+static int bn_limit_num_mont=8;   /* (1<<bn_limit_bits_mont) */
+
+void BN_set_params(int mult, int high, int low, int mont)
+        {
+        if (mult >= 0)
+                {
+                if (mult > (sizeof(int)*8)-1)
+                        mult=sizeof(int)*8-1;
+                bn_limit_bits=mult;
+                bn_limit_num=1<<mult;
+                }
+        if (high >= 0)
+                {
+                if (high > (sizeof(int)*8)-1)
+                        high=sizeof(int)*8-1;
+                bn_limit_bits_high=high;
+                bn_limit_num_high=1<<high;
+                }
+        if (low >= 0)
+                {
+                if (low > (sizeof(int)*8)-1)
+                        low=sizeof(int)*8-1;
+                bn_limit_bits_low=low;
+                bn_limit_num_low=1<<low;
+                }
+        if (mont >= 0)
+                {
+                if (mont > (sizeof(int)*8)-1)
+                        mont=sizeof(int)*8-1;
+                bn_limit_bits_mont=mont;
+                bn_limit_num_mont=1<<mont;
+                }
+        }
+
+int BN_get_params(int which)
+        {
+        if      (which == 0) return(bn_limit_bits);
+        else if (which == 1) return(bn_limit_bits_high);
+        else if (which == 2) return(bn_limit_bits_low);
+        else if (which == 3) return(bn_limit_bits_mont);
+        else return(0);
+        }
+
+const BIGNUM *BN_value_one(void)
         {
         static BN_ULONG data_one=1L;
         static BIGNUM const_one={&data_one,1,1,0};
@@ -70,7 +136,7 @@ BIGNUM *BN_value_one()
         return(&const_one);
         }
 
-char *BN_options()
+char *BN_options(void)
         {
         static int init=0;
         static char data[16];
@@ -89,10 +155,9 @@ char *BN_options()
         return(data);
         }
 
-int BN_num_bits_word(l)
-BN_ULONG l;
+int BN_num_bits_word(BN_ULONG l)
         {
-        static char bits[256]={
+        static const char bits[256]={
                 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
                 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
                 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
@@ -111,24 +176,24 @@ BN_ULONG l;
                 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                 };
 
-#ifdef SIXTY_FOUR_BIT_LONG
+#if defined(SIXTY_FOUR_BIT_LONG)
         if (l & 0xffffffff00000000L)
                 {
                 if (l & 0xffff000000000000L)
                         {
                         if (l & 0xff00000000000000L)
                                 {
-                                return(bits[l>>56]+56);
+                                return(bits[(int)(l>>56)]+56);
                                 }
-                        else    return(bits[l>>48]+48);
+                        else    return(bits[(int)(l>>48)]+48);
                         }
                 else
                         {
                         if (l & 0x0000ff0000000000L)
                                 {
-                                return(bits[l>>40]+40);
+                                return(bits[(int)(l>>40)]+40);
                                 }
-                        else    return(bits[l>>32]+32);
+                        else    return(bits[(int)(l>>32)]+32);
                         }
                 }
         else
@@ -140,17 +205,17 @@ BN_ULONG l;
                         {
                         if (l & 0xff00000000000000LL)
                                 {
-                                return(bits[l>>56]+56);
+                                return(bits[(int)(l>>56)]+56);
                                 }
-                        else    return(bits[l>>48]+48);
+                        else    return(bits[(int)(l>>48)]+48);
                         }
                 else
                         {
                         if (l & 0x0000ff0000000000LL)
                                 {
-                                return(bits[l>>40]+40);
+                                return(bits[(int)(l>>40)]+40);
                                 }
-                        else    return(bits[l>>32]+32);
+                        else    return(bits[(int)(l>>32)]+32);
                         }
                 }
         else
@@ -161,161 +226,256 @@ BN_ULONG l;
                 if (l & 0xffff0000L)
                         {
                         if (l & 0xff000000L)
-                                return(bits[l>>24L]+24);
-                        else    return(bits[l>>16L]+16);
+                                return(bits[(int)(l>>24L)]+24);
+                        else    return(bits[(int)(l>>16L)]+16);
                         }
                 else
 #endif
                         {
 #if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
                         if (l & 0xff00L)
-                                return(bits[l>>8]+8);
+                                return(bits[(int)(l>>8)]+8);
                         else    
 #endif
-                                return(bits[l   ]  );
+                                return(bits[(int)(l   )]  );
                         }
                 }
         }
 
-int BN_num_bits(a)
-BIGNUM *a;
+int BN_num_bits(const BIGNUM *a)
         {
         BN_ULONG l;
         int i;
 
+        bn_check_top(a);
+
         if (a->top == 0) return(0);
         l=a->d[a->top-1];
+        assert(l != 0);
         i=(a->top-1)*BN_BITS2;
-        if (l == 0)
-                {
-#if !defined(NO_STDIO) && !defined(WIN16)
-                fprintf(stderr,"BAD TOP VALUE\n");
-#endif
-                abort();
-                }
         return(i+BN_num_bits_word(l));
         }
 
-void BN_clear_free(a)
-BIGNUM *a;
+void BN_clear_free(BIGNUM *a)
         {
+        int i;
+
         if (a == NULL) return;
         if (a->d != NULL)
                 {
-                memset(a->d,0,a->max*sizeof(a->d[0]));
-                Free(a->d);
+                memset(a->d,0,a->dmax*sizeof(a->d[0]));
+                if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
+                        OPENSSL_free(a->d);
                 }
+        i=BN_get_flags(a,BN_FLG_MALLOCED);
         memset(a,0,sizeof(BIGNUM));
-        Free(a);
+        if (i)
+                OPENSSL_free(a);
         }
 
-void BN_free(a)
-BIGNUM *a;
+void BN_free(BIGNUM *a)
         {
         if (a == NULL) return;
-        if (a->d != NULL) Free(a->d);
-        Free(a);
+        if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
+                OPENSSL_free(a->d);
+        a->flags|=BN_FLG_FREE; /* REMOVE? */
+        if (a->flags & BN_FLG_MALLOCED)
+                OPENSSL_free(a);
         }
 
-BIGNUM *BN_new()
+void BN_init(BIGNUM *a)
+        {
+        memset(a,0,sizeof(BIGNUM));
+        }
+
+BIGNUM *BN_new(void)
         {
         BIGNUM *ret;
-        BN_ULONG *p;
 
-        ret=(BIGNUM *)Malloc(sizeof(BIGNUM));
-        if (ret == NULL) goto err;
+        if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
+                {
+                BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
+                return(NULL);
+                }
+        ret->flags=BN_FLG_MALLOCED;
         ret->top=0;
         ret->neg=0;
-        ret->max=(BN_DEFAULT_BITS/BN_BITS2);
-        p=(BN_ULONG *)Malloc(sizeof(BN_ULONG)*(ret->max+1));
-        if (p == NULL) goto err;
-        ret->d=p;
-
-        memset(p,0,(ret->max+1)*sizeof(p[0]));
+        ret->dmax=0;
+        ret->d=NULL;
         return(ret);
-err:
-        BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
-        return(NULL);
         }
 
-BN_CTX *BN_CTX_new()
+/* This is used both by bn_expand2() and bn_dup_expand() */
+/* The caller MUST check that words > b->dmax before calling this */
+static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
         {
-        BN_CTX *ret;
-        BIGNUM *n;
-        int i,j;
+        BN_ULONG *A,*a = NULL;
+        const BN_ULONG *B;
+        int i;
 
-        ret=(BN_CTX *)Malloc(sizeof(BN_CTX));
-        if (ret == NULL) goto err2;
+        if (words > (INT_MAX/(4*BN_BITS2)))
+                {
+                BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
+                return NULL;
+                }
 
-        for (i=0; i<BN_CTX_NUM; i++)
+        bn_check_top(b);        
+        if (BN_get_flags(b,BN_FLG_STATIC_DATA))
                 {
-                n=BN_new();
-                if (n == NULL) goto err;
-                ret->bn[i]=n;
+                BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
+                return(NULL);
+                }
+        a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*(words+1));
+        if (A == NULL)
+                {
+                BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
+                return(NULL);
+                }
+#if 1
+        B=b->d;
+        /* Check if the previous number needs to be copied */
+        if (B != NULL)
+                {
+                for (i=b->top>>2; i>0; i--,A+=4,B+=4)
+                        {
+                        /*
+                         * The fact that the loop is unrolled
+                         * 4-wise is a tribute to Intel. It's
+                         * the one that doesn't have enough
+                         * registers to accomodate more data.
+                         * I'd unroll it 8-wise otherwise:-)
+                         *
+                         *              <appro@fy.chalmers.se>
+                         */
+                        BN_ULONG a0,a1,a2,a3;
+                        a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
+                        A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
+                        }
+                switch (b->top&3)
+                        {
+                case 3: A[2]=B[2];
+                case 2: A[1]=B[1];
+                case 1: A[0]=B[0];
+                case 0: /* workaround for ultrix cc: without 'case 0', the optimizer does
+                         * the switch table by doing a=top&3; a--; goto jump_table[a];
+                         * which fails for top== 0 */
+                        ;
+                        }
                 }
 
-        /* There is actually an extra one, this is for debugging my
-         * stuff */
-        ret->bn[BN_CTX_NUM]=NULL;
+        /* Now need to zero any data between b->top and b->max */
+        /* XXX Why? */
 
-        ret->tos=0;
-        return(ret);
-err:
-        for (j=0; j<i; j++)
-                BN_free(ret->bn[j]);
-        Free(ret);
-err2:
-        BNerr(BN_F_BN_CTX_NEW,ERR_R_MALLOC_FAILURE);
-        return(NULL);
+        A= &(a[b->top]);
+        for (i=(words - b->top)>>3; i>0; i--,A+=8)
+                {
+                A[0]=0; A[1]=0; A[2]=0; A[3]=0;
+                A[4]=0; A[5]=0; A[6]=0; A[7]=0;
+                }
+        for (i=(words - b->top)&7; i>0; i--,A++)
+                A[0]=0;
+#else
+        memset(A,0,sizeof(BN_ULONG)*(words+1));
+        memcpy(A,b->d,sizeof(b->d[0])*b->top);
+#endif
+                
+        return(a);
         }
 
-void BN_CTX_free(c)
-BN_CTX *c;
+/* This is an internal function that can be used instead of bn_expand2()
+ * when there is a need to copy BIGNUMs instead of only expanding the
+ * data part, while still expanding them.
+ * Especially useful when needing to expand BIGNUMs that are declared
+ * 'const' and should therefore not be changed.
+ * The reason to use this instead of a BN_dup() followed by a bn_expand2()
+ * is memory allocation overhead.  A BN_dup() followed by a bn_expand2()
+ * will allocate new memory for the BIGNUM data twice, and free it once,
+ * while bn_dup_expand() makes sure allocation is made only once.
+ */
+
+BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
         {
-        int i;
+        BIGNUM *r = NULL;
+
+        if (words > b->dmax)
+                {
+                BN_ULONG *a = bn_expand_internal(b, words);
 
-        for (i=0; i<BN_CTX_NUM; i++)
-                BN_clear_free(c->bn[i]);
-        Free(c);
+                if (a)
+                        {
+                        r = BN_new();
+                        if (r)
+                                {
+                                r->top = b->top;
+                                r->dmax = words;
+                                r->neg = b->neg;
+                                r->d = a;
+                                }
+                        else
+                                {
+                                /* r == NULL, BN_new failure */
+                                OPENSSL_free(a);
+                                }
+                        }
+                /* If a == NULL, there was an error in allocation in
+                   bn_expand_internal(), and NULL should be returned */
+                }
+        else
+                {
+                r = BN_dup(b);
+                }
+
+        return r;
         }
 
-BIGNUM *bn_expand2(b, words)
-BIGNUM *b;
-int words;
-        {
-        BN_ULONG *p;
+/* This is an internal function that should not be used in applications.
+ * It ensures that 'b' has enough room for a 'words' word number number.
+ * It is mostly used by the various BIGNUM routines. If there is an error,
+ * NULL is returned. If not, 'b' is returned. */
 
-        if (words > b->max)
+BIGNUM *bn_expand2(BIGNUM *b, int words)
+        {
+        if (words > b->dmax)
                 {
-                p=(BN_ULONG *)Realloc(b->d,sizeof(BN_ULONG)*(words+1));
-                if (p == NULL)
+                BN_ULONG *a = bn_expand_internal(b, words);
+
+                if (a)
                         {
-                        BNerr(BN_F_BN_EXPAND2,ERR_R_MALLOC_FAILURE);
-                        return(NULL);
+                        if (b->d)
+                                OPENSSL_free(b->d);
+                        b->d=a;
+                        b->dmax=words;
                         }
-                b->d=p;
-                memset(&(p[b->max]),0,((words+1)-b->max)*sizeof(BN_ULONG));
-                b->max=words;
+                else
+                        b = NULL;
                 }
-        return(b);
+        return b;
         }
 
-BIGNUM *BN_dup(a)
-BIGNUM *a;
+BIGNUM *BN_dup(const BIGNUM *a)
         {
-        BIGNUM *r;
+        BIGNUM *r, *t;
 
-        r=BN_new();
-        if (r == NULL) return(NULL);
-        return((BIGNUM *)BN_copy(r,a));
+        if (a == NULL) return NULL;
+
+        bn_check_top(a);
+
+        t = BN_new();
+        if (t == NULL) return(NULL);
+        r = BN_copy(t, a);
+        /* now  r == t || r == NULL */
+        if (r == NULL)
+                BN_free(t);
+        return r;
         }
 
-BIGNUM *BN_copy(a, b)
-BIGNUM *a;
-BIGNUM *b;
+BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
         {
         int i;
-        BN_ULONG *A,*B;
+        BN_ULONG *A;
+        const BN_ULONG *B;
+
+        bn_check_top(b);
 
         if (a == b) return(a);
         if (bn_wexpand(a,b->top) == NULL) return(NULL);
@@ -323,35 +483,18 @@ BIGNUM *b;
 #if 1
         A=a->d;
         B=b->d;
-        for (i=b->top&(~7); i>0; i-=8)
-                {
-                A[0]=B[0];
-                A[1]=B[1];
-                A[2]=B[2];
-                A[3]=B[3];
-                A[4]=B[4];
-                A[5]=B[5];
-                A[6]=B[6];
-                A[7]=B[7];
-                A+=8;
-                B+=8;
-                }
-        switch (b->top&7)
-                {
-        case 7:
-                A[6]=B[6];
-        case 6:
-                A[5]=B[5];
-        case 5:
-                A[4]=B[4];
-        case 4:
-                A[3]=B[3];
-        case 3:
-                A[2]=B[2];
-        case 2:
-                A[1]=B[1];
-        case 1:
-                A[0]=B[0];
+        for (i=b->top>>2; i>0; i--,A+=4,B+=4)
+                {
+                BN_ULONG a0,a1,a2,a3;
+                a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
+                A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
+                }
+        switch (b->top&3)
+                {
+                case 3: A[2]=B[2];
+                case 2: A[1]=B[1];
+                case 1: A[0]=B[0];
+                case 0: ; /* ultrix cc workaround, see comments in bn_expand_internal */
                 }
 #else
         memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
@@ -359,52 +502,76 @@ BIGNUM *b;
 
 /*      memset(&(a->d[b->top]),0,sizeof(a->d[0])*(a->max-b->top));*/
         a->top=b->top;
-        if (a->top == 0)
+        if ((a->top == 0) && (a->d != NULL))
                 a->d[0]=0;
         a->neg=b->neg;
         return(a);
         }
 
-void BN_clear(a)
-BIGNUM *a;
+void BN_swap(BIGNUM *a, BIGNUM *b)
+        {
+        int flags_old_a, flags_old_b;
+        BN_ULONG *tmp_d;
+        int tmp_top, tmp_dmax, tmp_neg;
+        
+        flags_old_a = a->flags;
+        flags_old_b = b->flags;
+
+        tmp_d = a->d;
+        tmp_top = a->top;
+        tmp_dmax = a->dmax;
+        tmp_neg = a->neg;
+        
+        a->d = b->d;
+        a->top = b->top;
+        a->dmax = b->dmax;
+        a->neg = b->neg;
+        
+        b->d = tmp_d;
+        b->top = tmp_top;
+        b->dmax = tmp_dmax;
+        b->neg = tmp_neg;
+        
+        a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
+        b->flags = (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
+        }
+
+
+void BN_clear(BIGNUM *a)
         {
-        memset(a->d,0,a->max*sizeof(a->d[0]));
+        if (a->d != NULL)
+                memset(a->d,0,a->dmax*sizeof(a->d[0]));
         a->top=0;
         a->neg=0;
         }
 
-unsigned long BN_get_word(a)
-BIGNUM *a;
+BN_ULONG BN_get_word(const BIGNUM *a)
         {
         int i,n;
-        unsigned long ret=0;
+        BN_ULONG ret=0;
 
         n=BN_num_bytes(a);
-        if (n > sizeof(unsigned long))
-#ifdef SIXTY_FOUR_BIT_LONG
+        if (n > sizeof(BN_ULONG))
                 return(BN_MASK2);
-#else
-                return(0xFFFFFFFFL);
-#endif
         for (i=a->top-1; i>=0; i--)
                 {
 #ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
                 ret<<=BN_BITS4; /* stops the compiler complaining */
                 ret<<=BN_BITS4;
+#else
+                ret=0;
 #endif
                 ret|=a->d[i];
                 }
         return(ret);
         }
 
-int BN_set_word(a,w)
-BIGNUM *a;
-unsigned long w;
+int BN_set_word(BIGNUM *a, BN_ULONG w)
         {
         int i,n;
-        if (bn_expand(a,sizeof(unsigned long)*8) == NULL) return(0);
+        if (bn_expand(a,sizeof(BN_ULONG)*8) == NULL) return(0);
 
-        n=sizeof(unsigned long)/BN_BYTES;
+        n=sizeof(BN_ULONG)/BN_BYTES;
         a->neg=0;
         a->top=0;
         a->d[0]=(BN_ULONG)w&BN_MASK2;
@@ -417,6 +584,8 @@ unsigned long w;
 #ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
                 w>>=BN_BITS4;
                 w>>=BN_BITS4;
+#else
+                w=0;
 #endif
                 a->d[i]=(BN_ULONG)w&BN_MASK2;
                 if (a->d[i] != 0) a->top=i+1;
@@ -424,11 +593,7 @@ unsigned long w;
         return(1);
         }
 
-/* ignore negative */
-BIGNUM *BN_bin2bn(s, len, ret)
-unsigned char *s;
-int len;
-BIGNUM *ret;
+BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
         {
         unsigned int i,m;
         unsigned int n;
@@ -448,6 +613,7 @@ BIGNUM *ret;
         i=((n-1)/BN_BYTES)+1;
         m=((n-1)%(BN_BYTES));
         ret->top=i;
+        ret->neg=0;
         while (n-- > 0)
                 {
                 l=(l<<8L)| *(s++);
@@ -465,9 +631,7 @@ BIGNUM *ret;
         }
 
 /* ignore negative */
-int BN_bn2bin(a, to)
-BIGNUM *a;
-unsigned char *to;
+int BN_bn2bin(const BIGNUM *a, unsigned char *to)
         {
         int n,i;
         BN_ULONG l;
@@ -481,13 +645,14 @@ unsigned char *to;
         return(n);
         }
 
-int BN_ucmp(a, b)
-BIGNUM *a;
-BIGNUM *b;
+int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
         {
         int i;
         BN_ULONG t1,t2,*ap,*bp;
 
+        bn_check_top(a);
+        bn_check_top(b);
+
         i=a->top-b->top;
         if (i != 0) return(i);
         ap=a->d;
@@ -502,9 +667,7 @@ BIGNUM *b;
         return(0);
         }
 
-int BN_cmp(a, b)
-BIGNUM *a;
-BIGNUM *b;
+int BN_cmp(const BIGNUM *a, const BIGNUM *b)
         {
         int i;
         int gt,lt;
@@ -519,6 +682,10 @@ BIGNUM *b;
                 else
                         return(0);
                 }
+
+        bn_check_top(a);
+        bn_check_top(b);
+
         if (a->neg != b->neg)
                 {
                 if (a->neg)
@@ -541,27 +708,25 @@ BIGNUM *b;
         return(0);
         }
 
-int BN_set_bit(a, n)
-BIGNUM *a;
-int n;
+int BN_set_bit(BIGNUM *a, int n)
         {
-        int i,j;
+        int i,j,k;
 
         i=n/BN_BITS2;
         j=n%BN_BITS2;
         if (a->top <= i)
                 {
-                if (bn_expand(a,n) == NULL) return(0);
+                if (bn_wexpand(a,i+1) == NULL) return(0);
+                for(k=a->top; k<i+1; k++)
+                        a->d[k]=0;
                 a->top=i+1;
                 }
 
-        a->d[i]|=(1L<<j);
+        a->d[i]|=(((BN_ULONG)1)<<j);
         return(1);
         }
 
-int BN_clear_bit(a, n)
-BIGNUM *a;
-int n;
+int BN_clear_bit(BIGNUM *a, int n)
         {
         int i,j;
 
@@ -569,13 +734,12 @@ int n;
         j=n%BN_BITS2;
         if (a->top <= i) return(0);
 
-        a->d[i]&=(~(1L<<j));
+        a->d[i]&=(~(((BN_ULONG)1)<<j));
+        bn_fix_top(a);
         return(1);
         }
 
-int BN_is_bit_set(a, n)
-BIGNUM *a;
-int n;
+int BN_is_bit_set(const BIGNUM *a, int n)
         {
         int i,j;
 
@@ -586,9 +750,7 @@ int n;
         return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
         }
 
-int BN_mask_bits(a,n)
-BIGNUM *a;
-int n;
+int BN_mask_bits(BIGNUM *a, int n)
         {
         int b,w;
 
@@ -601,11 +763,56 @@ int n;
                 {
                 a->top=w+1;
                 a->d[w]&= ~(BN_MASK2<<b);
-                while ((w >= 0) && (a->d[w] == 0))
+                }
+        bn_fix_top(a);
+        return(1);
+        }
+
+int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
+        {
+        int i;
+        BN_ULONG aa,bb;
+
+        aa=a[n-1];
+        bb=b[n-1];
+        if (aa != bb) return((aa > bb)?1:-1);
+        for (i=n-2; i>=0; i--)
+                {
+                aa=a[i];
+                bb=b[i];
+                if (aa != bb) return((aa > bb)?1:-1);
+                }
+        return(0);
+        }
+
+/* Here follows a specialised variants of bn_cmp_words().  It has the
+   property of performing the operation on arrays of different sizes.
+   The sizes of those arrays is expressed through cl, which is the
+   common length ( basicall, min(len(a),len(b)) ), and dl, which is the
+   delta between the two lengths, calculated as len(a)-len(b).
+   All lengths are the number of BN_ULONGs...  */
+
+int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
+        int cl, int dl)
+        {
+        int n,i;
+        n = cl-1;
+
+        if (dl < 0)
+                {
+                for (i=dl; i<0; i++)
                         {
-                        a->top--;
-                        w--;
+                        if (b[n-i] != 0)
+                                return -1; /* a < b */
                         }
                 }
-        return(1);
+        if (dl > 0)
+                {
+                for (i=dl; i>0; i--)
+                        {
+                        if (a[n+i] != 0)
+                                return 1; /* a > b */
+                        }
+                }
+        return bn_cmp_words(a,b,cl);
         }