always reject data >= n

4 files changed, 45 insertions, 2 deletions

diff --git a/CHANGES b/CHANGES
index 4d0063fb85..7ec2fc8fc3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,18 @@
 
  Changes between 0.9.6b and 0.9.6c  [XX xxx XXXX]
 
+  *) In
+
+          RSA_eay_public_encrypt
+          RSA_eay_private_decrypt
+          RSA_eay_private_encrypt (signing)
+          RSA_eay_public_decrypt (signature verification)
+
+     (default implementations for RSA_public_encrypt,
+     RSA_private_decrypt, RSA_private_encrypt, RSA_public_decrypt),
+     always reject numbers >= n.
+     [Bodo Moeller]
+
   *) In crypto/rand/md_rand.c, set 'locking_thread' to current thread's ID
      *before* setting the 'crypto_lock_rand' flag.  The previous code had
      a race condition if 0 is a valid thread ID.
diff --git a/crypto/rsa/rsa.h b/crypto/rsa/rsa.h
index fef4ef5a2d..b029cbc3a4 100644
--- a/crypto/rsa/rsa.h
+++ b/crypto/rsa/rsa.h
@@ -316,6 +316,7 @@ void *RSA_get_ex_data(RSA *r, int idx);
 #define RSA_R_DATA_GREATER_THAN_MOD_LEN			 108
 #define RSA_R_DATA_TOO_LARGE				 109
 #define RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE		 110
+#define RSA_R_DATA_TOO_LARGE_FOR_MODULUS		 132
 #define RSA_R_DATA_TOO_SMALL				 111
 #define RSA_R_DATA_TOO_SMALL_FOR_KEY_SIZE		 122
 #define RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY		 112
diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index 3e38320257..cafdc419e2 100644
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -78,8 +78,8 @@ static int RSA_eay_finish(RSA *rsa);
 static RSA_METHOD rsa_pkcs1_eay_meth={
 	"Eric Young's PKCS#1 RSA",
 	RSA_eay_public_encrypt,
-	RSA_eay_public_decrypt,
-	RSA_eay_private_encrypt,
+	RSA_eay_public_decrypt, /* signature verification */
+	RSA_eay_private_encrypt, /* signing */
 	RSA_eay_private_decrypt,
 	RSA_eay_mod_exp,
 	BN_mod_exp_mont,
@@ -136,6 +136,13 @@ static int RSA_eay_public_encrypt(int flen, unsigned char *from,
 
 	if (BN_bin2bn(buf,num,&f) == NULL) goto err;
 	
+	if (BN_ucmp(&f, rsa->n) >= 0)
+		{	
+		/* usually the padding functions would catch this */
+		RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+		goto err;
+		}
+
 	if ((rsa->_method_mod_n == NULL) && (rsa->flags & RSA_FLAG_CACHE_PUBLIC))
 		{
 		BN_MONT_CTX* bn_mont_ctx;
@@ -183,6 +190,7 @@ err:
 	return(r);
 	}
 
+/* signing */
 static int RSA_eay_private_encrypt(int flen, unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
@@ -218,6 +226,13 @@ static int RSA_eay_private_encrypt(int flen, unsigned char *from,
 	if (i <= 0) goto err;
 
 	if (BN_bin2bn(buf,num,&f) == NULL) goto err;
+	
+	if (BN_ucmp(&f, rsa->n) >= 0)
+		{	
+		/* usually the padding functions would catch this */
+		RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+		goto err;
+		}
 
 	if ((rsa->flags & RSA_FLAG_BLINDING) && (rsa->blinding == NULL))
 		RSA_blinding_on(rsa,ctx);
@@ -292,6 +307,12 @@ static int RSA_eay_private_decrypt(int flen, unsigned char *from,
 	/* make data into a big number */
 	if (BN_bin2bn(from,(int)flen,&f) == NULL) goto err;
 
+	if (BN_ucmp(&f, rsa->n) >= 0)
+		{
+		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+		goto err;
+		}
+
 	if ((rsa->flags & RSA_FLAG_BLINDING) && (rsa->blinding == NULL))
 		RSA_blinding_on(rsa,ctx);
 	if (rsa->flags & RSA_FLAG_BLINDING)
@@ -352,6 +373,7 @@ err:
 	return(r);
 	}
 
+/* signature verification */
 static int RSA_eay_public_decrypt(int flen, unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
@@ -383,6 +405,13 @@ static int RSA_eay_public_decrypt(int flen, unsigned char *from,
 		}
 
 	if (BN_bin2bn(from,flen,&f) == NULL) goto err;
+
+	if (BN_ucmp(&f, rsa->n) >= 0)
+		{
+		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+		goto err;
+		}
+
 	/* do the decrypt */
 	if ((rsa->_method_mod_n == NULL) && (rsa->flags & RSA_FLAG_CACHE_PUBLIC))
 		{
diff --git a/crypto/rsa/rsa_err.c b/crypto/rsa/rsa_err.c
index 1cde7c0da4..bff7cf5d12 100644
--- a/crypto/rsa/rsa_err.c
+++ b/crypto/rsa/rsa_err.c
@@ -106,6 +106,7 @@ static ERR_STRING_DATA RSA_str_reasons[]=
 {RSA_R_DATA_GREATER_THAN_MOD_LEN         ,"data greater than mod len"},
 {RSA_R_DATA_TOO_LARGE                    ,"data too large"},
 {RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE       ,"data too large for key size"},
+{RSA_R_DATA_TOO_LARGE_FOR_MODULUS        ,"data too large for modulus"},
 {RSA_R_DATA_TOO_SMALL                    ,"data too small"},
 {RSA_R_DATA_TOO_SMALL_FOR_KEY_SIZE       ,"data too small for key size"},
 {RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY        ,"digest too big for rsa key"},