[freenet-cvs] r11714 - trunk/freenet/src/freenet/crypt

[t...@freenetproject.org]

Author: toad
Date: 2007-02-09 19:04:07 +0000 (Fri, 09 Feb 2007)
New Revision: 11714

Modified:
   trunk/freenet/src/freenet/crypt/DSA.java
Log:
Throw if m > q

Modified: trunk/freenet/src/freenet/crypt/DSA.java
===================================================================
--- trunk/freenet/src/freenet/crypt/DSA.java    2007-02-09 18:19:18 UTC (rev 
11713)
+++ trunk/freenet/src/freenet/crypt/DSA.java    2007-02-09 19:04:07 UTC (rev 
11714)
@@ -26,6 +26,8 @@
                        RandomSource random) {
                if(k.signum() == -1) throw new IllegalArgumentException();
                if(m.signum() == -1) throw new IllegalArgumentException();
+               if(m.compareTo(g.getQ()) != -1)
+                       throw new IllegalArgumentException();
                BigInteger r=g.getG().modPow(k, g.getP()).mod(g.getQ());

                BigInteger kInv=k.modInverse(g.getQ());
@@ -89,9 +91,17 @@
                if(m.signum() == -1) throw new IllegalArgumentException();
                try {
                        // 0<r<q has to be true
-                       if((sig.getR().compareTo(BigInteger.ZERO) < 1) || 
(kp.getQ().compareTo(sig.getR()) < 1)) return false;
+                       if((sig.getR().compareTo(BigInteger.ZERO) < 1) || 
(kp.getQ().compareTo(sig.getR()) < 1)) {
+                               if(Logger.shouldLog(Logger.MINOR, DSA.class))
+                                       Logger.minor(DSA.class, "r < 0 || r > 
q");
+                               return false;
+                       }
                        // 0<s<q has to be true as well
-                       if((sig.getS().compareTo(BigInteger.ZERO) < 1) || 
(kp.getQ().compareTo(sig.getS()) < 1)) return false;
+                       if((sig.getS().compareTo(BigInteger.ZERO) < 1) || 
(kp.getQ().compareTo(sig.getS()) < 1)) {
+                               if(Logger.shouldLog(Logger.MINOR, DSA.class))
+                                       Logger.minor(DSA.class, "s < 0 || s > 
q");
+                               return false;
+                       }

                        BigInteger w=sig.getS().modInverse(kp.getQ());
                        BigInteger u1=m.multiply(w).mod(kp.getQ());
@@ -103,6 +113,8 @@

                        //FIXME: is there a better way to handle this exception 
raised on the 'w=' line above?
                } catch (ArithmeticException e) {  // catch error raised by 
invalid data
+                       if(Logger.shouldLog(Logger.MINOR, DSA.class))
+                               Logger.minor(DSA.class, "Verify failed: "+e, e);
                        return false;                  // and report that that 
data is bad.
                }
        }