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 e4252251922f18d4eac7cc2f379763cf19c01fb1..2e0393e475fb918382a3ab2579ef392e99d116e9 100644 (file)
--- a/crypto/dh/dh_lib.c
+++ b/crypto/dh/dh_lib.c
@@ -104,7 +104,7 @@ 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 739fde65c4f34ceefd1005acc759d6074d142f9d..2eb8ee7ad5a2394e6f18bde42972fc230f55f4ef 100644 (file)
--- a/crypto/dsa/dsa_lib.c
+++ b/crypto/dsa/dsa_lib.c
@@ -111,7 +111,7 @@ 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 ec10b7e4a212baf3e36d97d248fb15dfe64aa3bd..9349abf03079fefd12c72b806a2d589da4f7c8b1 100644 (file)
--- a/crypto/ec/ec_key.c
+++ b/crypto/ec/ec_key.c
@@ -51,7 +51,7 @@ 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 61b1c16df665a45b6df6f7272c82550264cd1262..16e97c2a003daf4e6fdc36c9659bd45222d18913 100644 (file)
--- a/crypto/rsa/rsa_lib.c
+++ b/crypto/rsa/rsa_lib.c
@@ -115,7 +115,7 @@ 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);