Incremental cleanups to bn_lib.c.

- Add missing bn_check_top() calls and relocate some others
- Use BN_is_zero() where appropriate
- Remove assert()s that bn_check_top() is already covering
- Simplify the code in places (esp. bn_expand2())
- Only keep ambiguous zero handling if BN_STRICT isn't defined
- Remove some white-space and make some other aesthetic tweaks

diff --git a/crypto/bn/bn_lib.c b/crypto/bn/bn_lib.c
index 3bc67f9de2c267a5a9a4f5f23a38b284cae1bc80..d29a7cc8df299b584aafc53a2d08cfeac0333bd7 100644 (file)
--- a/crypto/bn/bn_lib.c
+++ b/crypto/bn/bn_lib.c
@@ -244,16 +244,11 @@ int BN_num_bits_word(BN_ULONG l)
 
 int BN_num_bits(const BIGNUM *a)
        {
-       BN_ULONG l;
-       int i;
-
+       int i = a->top - 1;
        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;
-       return(i+BN_num_bits_word(l));
+       if (BN_is_zero(a)) return 0;
+       return ((i*BN_BITS2) + BN_num_bits_word(a->d[i]));
        }
 
 void BN_clear_free(BIGNUM *a)
@@ -261,6 +256,7 @@ void BN_clear_free(BIGNUM *a)
        int i;
 
        if (a == NULL) return;
+       bn_check_top(a);
        if (a->d != NULL)
                {
                OPENSSL_cleanse(a->d,a->dmax*sizeof(a->d[0]));
@@ -276,6 +272,7 @@ void BN_clear_free(BIGNUM *a)
 void BN_free(BIGNUM *a)
        {
        if (a == NULL) return;
+       bn_check_top(a);
        if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
                OPENSSL_free(a->d);
        if (a->flags & BN_FLG_MALLOCED)
@@ -321,13 +318,13 @@ static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
        const BN_ULONG *B;
        int i;
 
+       bn_check_top(b);
+
        if (words > (INT_MAX/(4*BN_BITS2)))
                {
                BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
                return NULL;
                }
-
-       bn_check_top(b);        
        if (BN_get_flags(b,BN_FLG_STATIC_DATA))
                {
                BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
@@ -394,12 +391,14 @@ BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
        {
        BIGNUM *r = NULL;
 
+       bn_check_top(b);
+
        /* This function does not work if
         *      words <= b->dmax && top < words
         * because BN_dup() does not preserve 'dmax'!
         * (But bn_dup_expand() is not used anywhere yet.)
         */
-       
+
        if (words > b->dmax)
                {
                BN_ULONG *a = bn_expand_internal(b, words);
@@ -443,23 +442,19 @@ BIGNUM *bn_expand2(BIGNUM *b, int words)
        BN_ULONG *A;
        int i;
 
+       bn_check_top(b);
+
        if (words > b->dmax)
                {
                BN_ULONG *a = bn_expand_internal(b, words);
-
-               if (a)
-                       {
-                       if (b->d)
-                               OPENSSL_free(b->d);
-                       b->d=a;
-                       b->dmax=words;
-                       }
-               else
-                       b = NULL;
+               if(!a) return NULL;
+               if(b->d) OPENSSL_free(b->d);
+               b->d=a;
+               b->dmax=words;
                }
-       
+
        /* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
-       if ((b != NULL) && (b->top < b->dmax))
+       if (b->top < b->dmax)
                {
                A = &(b->d[b->top]);
                for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
@@ -471,26 +466,26 @@ BIGNUM *bn_expand2(BIGNUM *b, int words)
                        A[0]=0;
                assert(A == &(b->d[b->dmax]));
                }
-       else if(b) bn_check_top(b);
+       bn_check_top(b);
        return b;
        }
 
 BIGNUM *BN_dup(const BIGNUM *a)
        {
-       BIGNUM *r, *t;
+       BIGNUM *t;
 
        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)
+       if (t == NULL) return NULL;
+       if(!BN_copy(t, a))
+               {
                BN_free(t);
-       bn_check_top(r);
-       return r;
+               return NULL;
+               }
+       bn_check_top(t);
+       return t;
        }
 
 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
@@ -524,10 +519,11 @@ BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
        memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
 #endif
 
-/*     memset(&(a->d[b->top]),0,sizeof(a->d[0])*(a->max-b->top));*/
        a->top=b->top;
+#ifndef BN_STRICT
        if ((a->top == 0) && (a->d != NULL))
                a->d[0]=0;
+#endif
        a->neg=b->neg;
        bn_check_top(a);
        return(a);
@@ -540,18 +536,15 @@ BIGNUM *BN_ncopy(BIGNUM *a, const BIGNUM *b, size_t n)
        const BN_ULONG *B;
 
        bn_check_top(b);
-
        if (a == b)
                return a;
 
        min = (b->top < (int)n)? b->top: (int)n;
-
        if (!min)
                {
                BN_zero(a);
                return a;
                }
-
        if (bn_wexpand(a, min) == NULL)
                return NULL;
 
@@ -571,11 +564,8 @@ BIGNUM *BN_ncopy(BIGNUM *a, const BIGNUM *b, size_t n)
                case 0: ;
                }
        a->top = min;
-
        a->neg = b->neg;
        bn_correct_top(a);
-
-       bn_check_top(a);
        return(a);
        }
 
@@ -612,7 +602,6 @@ void BN_swap(BIGNUM *a, BIGNUM *b)
        bn_check_top(b);
        }
 
-
 void BN_clear(BIGNUM *a)
        {
        bn_check_top(a);
@@ -743,7 +732,7 @@ int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
                t1= ap[i];
                t2= bp[i];
                if (t1 != t2)
-                       return(t1 > t2?1:-1);
+                       return((t1 > t2) ? 1 : -1);
                }
        return(0);
        }
@@ -815,8 +804,8 @@ int BN_clear_bit(BIGNUM *a, int n)
        {
        int i,j;
 
-       if (n < 0)
-               return 0;
+       bn_check_top(a);
+       if (n < 0) return 0;
 
        i=n/BN_BITS2;
        j=n%BN_BITS2;
@@ -831,10 +820,11 @@ int BN_is_bit_set(const BIGNUM *a, int n)
        {
        int i,j;
 
-       if (n < 0) return(0);
+       bn_check_top(a);
+       if (n < 0) return 0;
        i=n/BN_BITS2;
        j=n%BN_BITS2;
-       if (a->top <= i) return(0);
+       if (a->top <= i) return 0;
        return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
        }
 
@@ -842,12 +832,12 @@ int BN_mask_bits(BIGNUM *a, int n)
        {
        int b,w;
 
-       if (n < 0)
-               return 0;
+       bn_check_top(a);
+       if (n < 0) return 0;
 
        w=n/BN_BITS2;
        b=n%BN_BITS2;
-       if (w >= a->top) return(0);
+       if (w >= a->top) return 0;
        if (b == 0)
                a->top=w;
        else