From f72f00d49549c6620d7101f5e9bf7963da6df9ee Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Fri, 27 May 2016 14:18:40 +0100
Subject: [PATCH] Parameter copy sanity checks.

Don't copy parameters is they're already present in the destination.
Return error if an attempt is made to copy different parameters to
destination. Update documentation.

If key type is not initialised return missing parameters

RT#4149

Reviewed-by: Richard Levitte <levitte@openssl.org>
---
 crypto/dh/dh_ameth.c        | 2 +-
 crypto/dsa/dsa_ameth.c      | 2 +-
 crypto/ec/ec_ameth.c        | 2 +-
 crypto/evp/p_lib.c          | 8 ++++++++
 doc/crypto/EVP_PKEY_cmp.pod | 4 +++-
 5 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/crypto/dh/dh_ameth.c b/crypto/dh/dh_ameth.c
index 222cb20b42..b7b37177c1 100644
--- a/crypto/dh/dh_ameth.c
+++ b/crypto/dh/dh_ameth.c
@@ -437,7 +437,7 @@ static int dh_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
 
 static int dh_missing_parameters(const EVP_PKEY *a)
 {
-    if (!a->pkey.dh->p || !a->pkey.dh->g)
+    if (a->pkey.dh == NULL || a->pkey.dh->p == NULL || a->pkey.dh->g == NULL)
         return 1;
     return 0;
 }
diff --git a/crypto/dsa/dsa_ameth.c b/crypto/dsa/dsa_ameth.c
index 1bb11a9ed5..a53247c074 100644
--- a/crypto/dsa/dsa_ameth.c
+++ b/crypto/dsa/dsa_ameth.c
@@ -266,7 +266,7 @@ static int dsa_missing_parameters(const EVP_PKEY *pkey)
 {
     DSA *dsa;
     dsa = pkey->pkey.dsa;
-    if ((dsa->p == NULL) || (dsa->q == NULL) || (dsa->g == NULL))
+    if (dsa == NULL || dsa->p == NULL || dsa->q == NULL || dsa->g == NULL)
         return 1;
     return 0;
 }
diff --git a/crypto/ec/ec_ameth.c b/crypto/ec/ec_ameth.c
index 684da95ab2..6567a2f398 100644
--- a/crypto/ec/ec_ameth.c
+++ b/crypto/ec/ec_ameth.c
@@ -292,7 +292,7 @@ static int ec_security_bits(const EVP_PKEY *pkey)
 
 static int ec_missing_parameters(const EVP_PKEY *pkey)
 {
-    if (EC_KEY_get0_group(pkey->pkey.ec) == NULL)
+    if (pkey->pkey.ec == NULL || EC_KEY_get0_group(pkey->pkey.ec) == NULL)
         return 1;
     return 0;
 }
diff --git a/crypto/evp/p_lib.c b/crypto/evp/p_lib.c
index 0b7884f9e5..0b50d3210e 100644
--- a/crypto/evp/p_lib.c
+++ b/crypto/evp/p_lib.c
@@ -84,6 +84,14 @@ int EVP_PKEY_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
         EVPerr(EVP_F_EVP_PKEY_COPY_PARAMETERS, EVP_R_MISSING_PARAMETERS);
         goto err;
     }
+
+    if (!EVP_PKEY_missing_parameters(to)) {
+        if (EVP_PKEY_cmp_parameters(to, from) == 1)
+            return 1;
+        EVPerr(EVP_F_EVP_PKEY_COPY_PARAMETERS, EVP_R_DIFFERENT_PARAMETERS);
+        return 0;
+    }
+
     if (from->ameth && from->ameth->param_copy)
         return from->ameth->param_copy(to, from);
  err:
diff --git a/doc/crypto/EVP_PKEY_cmp.pod b/doc/crypto/EVP_PKEY_cmp.pod
index 4e1f78bed1..7c9e582a81 100644
--- a/doc/crypto/EVP_PKEY_cmp.pod
+++ b/doc/crypto/EVP_PKEY_cmp.pod
@@ -21,7 +21,9 @@ parameters of B<pkey> are missing and 0 if they are present or the algorithm
 doesn't use parameters.
 
 The function EVP_PKEY_copy_parameters() copies the parameters from key
-B<from> to key B<to>.
+B<from> to key B<to>. An error is returned if the parameters are missing in
+B<from> or present in both B<from> and B<to> and mismatch. If the parameters
+in B<from> and B<to> are both present and match this function has no effect.
 
 The function EVP_PKEY_cmp_parameters() compares the parameters of keys
 B<a> and B<b>.
-- 
2.39.2