[openssl.org #2676] 1.0.1-beta1 issue: RSA exponent 1 is NOT ok

[Annie Yousar via RT]

This avoids the Ruby error.
***************************************************
issue:
RSA key with even exponent or 1 does not confirm with RFC 3447 (PKCS#1)
try e.g.
openssl rsa -check
with this key
-----BEGIN RSA PRIVATE KEY-----
MCUCAQACBQCHXk81AgEBAgEBAgMA90MCAwCMJwIBAQIBAQIDALXJ
-----END RSA PRIVATE KEY-----


solution:
add additional checks and use the already defined error constant
RSA_R_BAD_E_VALUE for it

patches:
--- openssl-1.0.1-beta1/crypto/rsa/rsa_chk.c    2002-12-08 06:24:25.000000000
+0100
+++ openssl-1.0.1-beta1.patch/crypto/rsa/rsa_chk.c      2012-01-06
09:03:27.372609300 +0100
@@ -74,5 +74,13 @@
                goto err;
                }
-
+
+       /* e > 1? */
+       r = BN_is_one(key->e);
+       if (r == 1)
+               {
+               ret = 0;
+               RSAerr(RSA_F_RSA_CHECK_KEY, RSA_R_BAD_E_VALUE);
+               }
+
        /* p prime? */
        r = BN_is_prime_ex(key->p, BN_prime_checks, NULL, NULL);

--- openssl-1.0.1-beta1/crypto/rsa/rsa_pmeth.c  2012-01-02
19:16:39.000000000 +0100
+++ openssl-1.0.1-beta1.patch/crypto/rsa/rsa_pmeth.c    2012-01-06
09:03:27.388234800 +0100
@@ -519,6 +519,9 @@

                case EVP_PKEY_CTRL_RSA_KEYGEN_PUBEXP:
-               if (!p2)
+               if ( (!p2) || (!BN_is_odd((BIGNUM*)p2)) || 
BN_is_one((BIGNUM*)p2) )
+                       {
+                       RSAerr(RSA_F_PKEY_RSA_CTRL, RSA_R_BAD_E_VALUE);
                        return -2;
+                       }
                rctx->pub_exp = p2;
                return 1;


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