From: Nicola Tuveri <nic.tuv@gmail.com>
Date: Wed, 5 Sep 2018 08:58:55 +0000 (+0300)
Subject: Fix segfault in RSA_free() (and DSA/DH/EC_KEY)
X-Git-Tag: OpenSSL_1_1_0j~47
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=c28a2ffd01dc1da932aa55d518b57a933cdc51be;p=oweals%2Fopenssl.git

Fix segfault in RSA_free() (and DSA/DH/EC_KEY)

`RSA_free()` and friends are called in case of error from
`RSA_new_method(ENGINE *e)` (or the respective equivalent functions).

For the rest of the description I'll talk about `RSA_*`, but the same
applies for the equivalent `DSA_free()`, `DH_free()`, `EC_KEY_free()`.

If `RSA_new_method()` fails because the engine does not implement the
required method, when `RSA_free(RSA *r)` is called,
`r->meth == NULL` and a segfault happens while checking if
`r->meth->finish` is defined.

This commit fixes this issue by ensuring that `r->meth` is not NULL
before dereferencing it to check for `r->meth->finish`.

Fixes #7102 .

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7121)
---

diff --git a/crypto/dh/dh_lib.c b/crypto/dh/dh_lib.c
index 716f4a4b0a..d277faa398 100644
--- a/crypto/dh/dh_lib.c
+++ b/crypto/dh/dh_lib.c
@@ -103,7 +103,7 @@ void DH_free(DH *r)
         return;
     REF_ASSERT_ISNT(i < 0);
 
-    if (r->meth->finish)
+    if (r->meth != NULL && r->meth->finish != NULL)
         r->meth->finish(r);
 #ifndef OPENSSL_NO_ENGINE
     ENGINE_finish(r->engine);
diff --git a/crypto/dsa/dsa_lib.c b/crypto/dsa/dsa_lib.c
index 9598846e3b..92758ca4c6 100644
--- a/crypto/dsa/dsa_lib.c
+++ b/crypto/dsa/dsa_lib.c
@@ -112,7 +112,7 @@ void DSA_free(DSA *r)
         return;
     REF_ASSERT_ISNT(i < 0);
 
-    if (r->meth->finish)
+    if (r->meth != NULL && r->meth->finish != NULL)
         r->meth->finish(r);
 #ifndef OPENSSL_NO_ENGINE
     ENGINE_finish(r->engine);
diff --git a/crypto/ec/ec_key.c b/crypto/ec/ec_key.c
index f1f0afb466..df35b64888 100644
--- a/crypto/ec/ec_key.c
+++ b/crypto/ec/ec_key.c
@@ -55,7 +55,7 @@ void EC_KEY_free(EC_KEY *r)
         return;
     REF_ASSERT_ISNT(i < 0);
 
-    if (r->meth->finish != NULL)
+    if (r->meth != NULL && r->meth->finish != NULL)
         r->meth->finish(r);
 
 #ifndef OPENSSL_NO_ENGINE
diff --git a/crypto/rsa/rsa_lib.c b/crypto/rsa/rsa_lib.c
index e1377a0690..97552fa335 100644
--- a/crypto/rsa/rsa_lib.c
+++ b/crypto/rsa/rsa_lib.c
@@ -112,7 +112,7 @@ void RSA_free(RSA *r)
         return;
     REF_ASSERT_ISNT(i < 0);
 
-    if (r->meth->finish)
+    if (r->meth != NULL && r->meth->finish != NULL)
         r->meth->finish(r);
 #ifndef OPENSSL_NO_ENGINE
     ENGINE_finish(r->engine);