Replace some 'sfree' calls of bignums with the proper 'freebn'.

[sgt/putty] / sshbn.c

diff --git a/sshbn.c b/sshbn.c
index fee219c..677b121 100644 (file)
--- a/sshbn.c
+++ b/sshbn.c
@@ -148,7 +148,7 @@ void freebn(Bignum b)
     /*
      * Burn the evidence, just in case.
      */
-    memset(b, 0, sizeof(b[0]) * (b[0] + 1));
+    smemclr(b, sizeof(b[0]) * (b[0] + 1));
     sfree(b);
 }
 
@@ -419,7 +419,7 @@ static void internal_mul(const BignumInt *a, const BignumInt *b,
             for (cp = cps, bp = b + len; cp--, bp-- > b ;) {
                 t = (MUL_WORD(*ap, *bp) + carry) + *cp;
                 *cp = (BignumInt) t;
-                carry = t >> BIGNUM_INT_BITS;
+                carry = (BignumInt)(t >> BIGNUM_INT_BITS);
             }
             *cp = carry;
         }
@@ -521,7 +521,7 @@ static void internal_mul_low(const BignumInt *a, const BignumInt *b,
             for (cp = cps, bp = b + len; bp--, cp-- > c ;) {
                 t = (MUL_WORD(*ap, *bp) + carry) + *cp;
                 *cp = (BignumInt) t;
-                carry = t >> BIGNUM_INT_BITS;
+                carry = (BignumInt)(t >> BIGNUM_INT_BITS);
             }
         }
     }
@@ -897,7 +897,7 @@ Bignum modpow(Bignum base_in, Bignum exp, Bignum mod)
 
     mninv = snewn(len, BignumInt);
     for (j = 0; j < len; j++)
-       mninv[len - 1 - j] = (j < inv[0] ? inv[j + 1] : 0);
+       mninv[len - 1 - j] = (j < (int)inv[0] ? inv[j + 1] : 0);
     freebn(inv);         /* we don't need this copy of it any more */
     /* Now negate mninv mod r, so it's the inverse of -n rather than +n. */
     x = snewn(len, BignumInt);
@@ -907,13 +907,13 @@ Bignum modpow(Bignum base_in, Bignum exp, Bignum mod)
 
     /* x = snewn(len, BignumInt); */ /* already done above */
     for (j = 0; j < len; j++)
-       x[len - 1 - j] = (j < base[0] ? base[j + 1] : 0);
+       x[len - 1 - j] = (j < (int)base[0] ? base[j + 1] : 0);
     freebn(base);        /* we don't need this copy of it any more */
 
     a = snewn(2*len, BignumInt);
     b = snewn(2*len, BignumInt);
     for (j = 0; j < len; j++)
-       a[2*len - 1 - j] = (j < rn[0] ? rn[j + 1] : 0);
+       a[2*len - 1 - j] = (j < (int)rn[0] ? rn[j + 1] : 0);
     freebn(rn);
 
     /* Scratch space for multiplies */
@@ -1018,6 +1018,13 @@ Bignum modmul(Bignum p, Bignum q, Bignum mod)
 
     pqlen = (p[0] > q[0] ? p[0] : q[0]);
 
+    /*
+     * Make sure that we're allowing enough space. The shifting below
+     * will underflow the vectors we allocate if pqlen is too small.
+     */
+    if (2*pqlen <= mlen)
+        pqlen = mlen/2 + 1;
+
     /* Allocate n of size pqlen, copy p to n */
     n = snewn(pqlen, BignumInt);
     i = pqlen - p[0];
@@ -1761,7 +1768,7 @@ char *bignum_decimal(Bignum x)
 #include <ctype.h>
 
 /*
- * gcc -g -O0 -DTESTBN -o testbn sshbn.c misc.c -I unix -I charset
+ * gcc -Wall -g -O0 -DTESTBN -o testbn sshbn.c misc.c conf.c tree234.c unix/uxmisc.c -I. -I unix -I charset
  *
  * Then feed to this program's standard input the output of
  * testdata/bignum.py .
@@ -1835,7 +1842,7 @@ int main(int argc, char **argv)
             Bignum a, b, c, p;
 
             if (ptrnum != 3) {
-                printf("%d: mul with %d parameters, expected 3\n", line);
+                printf("%d: mul with %d parameters, expected 3\n", line, ptrnum);
                 exit(1);
             }
             a = bignum_from_bytes(ptrs[0], ptrs[1]-ptrs[0]);
@@ -1864,11 +1871,49 @@ int main(int argc, char **argv)
             freebn(b);
             freebn(c);
             freebn(p);
+        } else if (!strcmp(buf, "modmul")) {
+            Bignum a, b, m, c, p;
+
+            if (ptrnum != 4) {
+                printf("%d: modmul with %d parameters, expected 4\n",
+                       line, ptrnum);
+                exit(1);
+            }
+            a = bignum_from_bytes(ptrs[0], ptrs[1]-ptrs[0]);
+            b = bignum_from_bytes(ptrs[1], ptrs[2]-ptrs[1]);
+            m = bignum_from_bytes(ptrs[2], ptrs[3]-ptrs[2]);
+            c = bignum_from_bytes(ptrs[3], ptrs[4]-ptrs[3]);
+            p = modmul(a, b, m);
+
+            if (bignum_cmp(c, p) == 0) {
+                passes++;
+            } else {
+                char *as = bignum_decimal(a);
+                char *bs = bignum_decimal(b);
+                char *ms = bignum_decimal(m);
+                char *cs = bignum_decimal(c);
+                char *ps = bignum_decimal(p);
+                
+                printf("%d: fail: %s * %s mod %s gave %s expected %s\n",
+                       line, as, bs, ms, ps, cs);
+                fails++;
+
+                sfree(as);
+                sfree(bs);
+                sfree(ms);
+                sfree(cs);
+                sfree(ps);
+            }
+            freebn(a);
+            freebn(b);
+            freebn(m);
+            freebn(c);
+            freebn(p);
         } else if (!strcmp(buf, "pow")) {
             Bignum base, expt, modulus, expected, answer;
 
             if (ptrnum != 4) {
-                printf("%d: mul with %d parameters, expected 3\n", line);
+                printf("%d: mul with %d parameters, expected 4\n", line, ptrnum);
                 exit(1);
             }