openssl security fixes, diff from markus@, ok & "commit it" djm@

http://www.openssl.org/news/secadv_20060928.txt for more

3 files changed, 10 insertions, 0 deletions

diff --git a/src/lib/libcrypto/dh/dh.h b/src/lib/libcrypto/dh/dh.h
index 8562d16fb7..582b34329f 100644
--- a/src/lib/libcrypto/dh/dh.h
+++ b/src/lib/libcrypto/dh/dh.h
@@ -70,6 +70,8 @@
 #include <openssl/crypto.h>
 #include <openssl/ossl_typ.h>
         
+#define OPENSSL_DH_MAX_MODULUS_BITS     10000
+
 #define DH_FLAG_CACHE_MONT_P     0x01
 #define DH_FLAG_NO_EXP_CONSTTIME 0x02 /* new with 0.9.7h; the built-in DH
                                        * implementation now uses constant time
@@ -213,6 +215,7 @@ void ERR_load_DH_strings(void);
 #define DH_R_BAD_GENERATOR                               101
 #define DH_R_NO_PRIVATE_VALUE                            100
 #define DH_R_INVALID_PUBKEY                              102
+#define DH_R_MODULUS_TOO_LARGE                           103
 
 #ifdef  __cplusplus
 }
diff --git a/src/lib/libcrypto/dh/dh_err.c b/src/lib/libcrypto/dh/dh_err.c
index 9336bfce6b..611067ef4a 100644
--- a/src/lib/libcrypto/dh/dh_err.c
+++ b/src/lib/libcrypto/dh/dh_err.c
@@ -84,6 +84,7 @@ static ERR_STRING_DATA DH_str_reasons[]=
 {ERR_REASON(DH_R_BAD_GENERATOR)          ,"bad generator"},
 {ERR_REASON(DH_R_NO_PRIVATE_VALUE)       ,"no private value"},
 {ERR_REASON(DH_R_INVALID_PUBKEY)         ,"invalid public key"},
+{ERR_REASON(DH_R_MODULUS_TOO_LARGE)      ,"modulus too large"},
 {0,NULL}
         };
 
diff --git a/src/lib/libcrypto/dh/dh_key.c b/src/lib/libcrypto/dh/dh_key.c
index e3641ec468..74de589204 100644
--- a/src/lib/libcrypto/dh/dh_key.c
+++ b/src/lib/libcrypto/dh/dh_key.c
@@ -181,6 +181,12 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
         int ret= -1;
         int check_result;
 
+        if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS)
+                {
+                DHerr(DH_F_DH_COMPUTE_KEY,DH_R_MODULUS_TOO_LARGE);
+                return -1;
+                }
+
         ctx = BN_CTX_new();
         if (ctx == NULL) goto err;
         BN_CTX_start(ctx);