1 files changed, 14 insertions, 53 deletions

diff --git a/src/lib/libcrypto/bn/bn_word.c b/src/lib/libcrypto/bn/bn_word.c
index ee7b87c45c..de610ce54c 100644
--- a/src/lib/libcrypto/bn/bn_word.c
+++ b/src/lib/libcrypto/bn/bn_word.c
@@ -69,10 +69,6 @@ BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
 #endif
         int i;
 
-        if (w == 0)
-                return (BN_ULONG)-1;
-
-        bn_check_top(a);
         w&=BN_MASK2;
         for (i=a->top-1; i>=0; i--)
                 {
@@ -89,24 +85,12 @@ BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
 
 BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)
         {
-        BN_ULONG ret = 0;
-        int i, j;
-
-        bn_check_top(a);
-        w &= BN_MASK2;
-
-        if (!w)
-                /* actually this an error (division by zero) */
-                return (BN_ULONG)-1;
-        if (a->top == 0)
-                return 0;
-
-        /* normalize input (so bn_div_words doesn't complain) */
-        j = BN_BITS2 - BN_num_bits_word(w);
-        w <<= j;
-        if (!BN_lshift(a, a, j))
-                return (BN_ULONG)-1;
+        BN_ULONG ret;
+        int i;
 
+        if (a->top == 0) return(0);
+        ret=0;
+        w&=BN_MASK2;
         for (i=a->top-1; i>=0; i--)
                 {
                 BN_ULONG l,d;
@@ -118,8 +102,6 @@ BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)
                 }
         if ((a->top > 0) && (a->d[a->top-1] == 0))
                 a->top--;
-        ret >>= j;
-        bn_check_top(a);
         return(ret);
         }
 
@@ -128,14 +110,9 @@ int BN_add_word(BIGNUM *a, BN_ULONG w)
         BN_ULONG l;
         int i;
 
-        bn_check_top(a);
-        w &= BN_MASK2;
+        if ((w & BN_MASK2) == 0)
+                return(1);
 
-        /* degenerate case: w is zero */
-        if (!w) return 1;
-        /* degenerate case: a is zero */
-        if(BN_is_zero(a)) return BN_set_word(a, w);
-        /* handle 'a' when negative */
         if (a->neg)
                 {
                 a->neg=0;
@@ -144,17 +121,15 @@ int BN_add_word(BIGNUM *a, BN_ULONG w)
                         a->neg=!(a->neg);
                 return(i);
                 }
-        /* Only expand (and risk failing) if it's possibly necessary */
-        if (((BN_ULONG)(a->d[a->top - 1] + 1) == 0) &&
-                        (bn_wexpand(a,a->top+1) == NULL))
-                return(0);
+        w&=BN_MASK2;
+        if (bn_wexpand(a,a->top+1) == NULL) return(0);
         i=0;
         for (;;)
                 {
                 if (i >= a->top)
                         l=w;
                 else
-                        l=(a->d[i]+w)&BN_MASK2;
+                        l=(a->d[i]+(BN_ULONG)w)&BN_MASK2;
                 a->d[i]=l;
                 if (w > l)
                         w=1;
@@ -164,7 +139,6 @@ int BN_add_word(BIGNUM *a, BN_ULONG w)
                 }
         if (i >= a->top)
                 a->top++;
-        bn_check_top(a);
         return(1);
         }
 
@@ -172,21 +146,10 @@ int BN_sub_word(BIGNUM *a, BN_ULONG w)
         {
         int i;
 
-        bn_check_top(a);
-        w &= BN_MASK2;
+        if ((w & BN_MASK2) == 0)
+                return(1);
 
-        /* degenerate case: w is zero */
-        if (!w) return 1;
-        /* degenerate case: a is zero */
-        if(BN_is_zero(a))
-                {
-                i = BN_set_word(a,w);
-                if (i != 0)
-                        BN_set_negative(a, 1);
-                return i;
-                }
-        /* handle 'a' when negative */
-        if (a->neg)
+        if (BN_is_zero(a) || a->neg)
                 {
                 a->neg=0;
                 i=BN_add_word(a,w);
@@ -194,6 +157,7 @@ int BN_sub_word(BIGNUM *a, BN_ULONG w)
                 return(i);
                 }
 
+        w&=BN_MASK2;
         if ((a->top == 1) && (a->d[0] < w))
                 {
                 a->d[0]=w-a->d[0];
@@ -217,7 +181,6 @@ int BN_sub_word(BIGNUM *a, BN_ULONG w)
                 }
         if ((a->d[i] == 0) && (i == (a->top-1)))
                 a->top--;
-        bn_check_top(a);
         return(1);
         }
 
@@ -225,7 +188,6 @@ int BN_mul_word(BIGNUM *a, BN_ULONG w)
         {
         BN_ULONG ll;
 
-        bn_check_top(a);
         w&=BN_MASK2;
         if (a->top)
                 {
@@ -241,7 +203,6 @@ int BN_mul_word(BIGNUM *a, BN_ULONG w)
                                 }
                         }
                 }
-        bn_check_top(a);
         return(1);
         }