X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=sshbn.c;h=0d64620da5c8728b59adf86e3334148cc76359bb;hb=eef0235a0f79e92f25f34782fc486c101fa703ee;hp=b40781ff2996dc65fe9659e4d15ef8921d1f52f3;hpb=8ab1433caaefef02a19e8e5ea74e5259fa719eae;p=PuTTY.git

diff --git a/sshbn.c b/sshbn.c
index b40781ff..0d64620d 100644
--- a/sshbn.c
+++ b/sshbn.c
@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <limits.h>
+#include <ctype.h>
 
 #include "misc.h"
 
@@ -102,6 +103,7 @@ typedef BignumInt *Bignum;
 
 BignumInt bnZero[1] = { 0 };
 BignumInt bnOne[2] = { 1, 1 };
+BignumInt bnTen[2] = { 1, 10 };
 
 /*
  * The Bignum format is an array of `BignumInt'. The first
@@ -117,7 +119,7 @@ BignumInt bnOne[2] = { 1, 1 };
  * nonzero.
  */
 
-Bignum Zero = bnZero, One = bnOne;
+Bignum Zero = bnZero, One = bnOne, Ten = bnTen;
 
 static Bignum newbn(int length)
 {
@@ -1233,21 +1235,67 @@ Bignum bignum_from_bytes(const unsigned char *data, int nbytes)
     return result;
 }
 
+Bignum bignum_from_bytes_le(const unsigned char *data, int nbytes)
+{
+    Bignum result;
+    int w, i;
+
+    assert(nbytes >= 0 && nbytes < INT_MAX/8);
+
+    w = (nbytes + BIGNUM_INT_BYTES - 1) / BIGNUM_INT_BYTES; /* bytes->words */
+
+    result = newbn(w);
+    for (i = 1; i <= w; i++)
+        result[i] = 0;
+    for (i = 0; i < nbytes; ++i) {
+        unsigned char byte = *data++;
+        result[1 + i / BIGNUM_INT_BYTES] |= byte << (8*i % BIGNUM_INT_BITS);
+    }
+
+    while (result[0] > 1 && result[result[0]] == 0)
+        result[0]--;
+    return result;
+}
+
+Bignum bignum_from_decimal(const char *decimal)
+{
+    Bignum result = copybn(Zero);
+
+    while (*decimal) {
+        Bignum tmp, tmp2;
+
+        if (!isdigit((unsigned char)*decimal)) {
+            freebn(result);
+            return 0;
+        }
+
+        tmp = bigmul(result, Ten);
+        tmp2 = bignum_from_long(*decimal - '0');
+        result = bigadd(tmp, tmp2);
+        freebn(tmp);
+        freebn(tmp2);
+
+        decimal++;
+    }
+
+    return result;
+}
+
 Bignum bignum_random_in_range(const Bignum lower, const Bignum upper)
 {
     Bignum ret = NULL;
+    unsigned char *bytes;
     int upper_len = bignum_bitcount(upper);
     int upper_bytes = upper_len / 8;
     int upper_bits = upper_len % 8;
     if (upper_bits) ++upper_bytes;
 
+    bytes = snewn(upper_bytes, unsigned char);
     do {
-        unsigned char *bytes;
         int i;
 
         if (ret) freebn(ret);
 
-        bytes = snewn(upper_bytes, unsigned char);
         for (i = 0; i < upper_bytes; ++i)
         {
             bytes[i] = (unsigned char)random_byte();
@@ -1260,6 +1308,8 @@ Bignum bignum_random_in_range(const Bignum lower, const Bignum upper)
 
         ret = bignum_from_bytes(bytes, upper_bytes);
     } while (bignum_cmp(ret, lower) < 0 || bignum_cmp(ret, upper) > 0);
+    smemclr(bytes, upper_bytes);
+    sfree(bytes);
 
     return ret;
 }