Fix use-after-free in tls_ctx_use_management_external_key

Commit 98bfeeb4 changed our openssl backend implementation of tls_ctx_use_management_external_key() to no longer use tls_ctx_load_cert_file_and_copy(), but still free'd 'cert'. Which it no longer should do. Credits go to Arne for spotting the issue (even though it was missed during the review).

The offending commit is only recently applied to the master branch, so was never part of a OpenVPN release. For that reason I did not do full impact analysis.

---
 src/openvpn/ssl_openssl.c | 1 -
 1 file changed, 1 deletion(-)

index fe4db604..7532773e 100644
@@ -1291,7 +1291,6 @@ tls_ctx_use_management_external_key(struct tls_root_ctx *ctx)
     /* get the public key */
     EVP_PKEY *pkey = X509_get0_pubkey(cert);
     ASSERT(pkey); /* NULL before SSL_CTX_use_certificate() is called */
-    X509_free(cert);
 
     if (EVP_PKEY_id(pkey) == EVP_PKEY_RSA)
     {

2.17.1

Am 07.10.18 um 13:00 schrieb Steffan Karger:

ACK. I already tested this on my on side.

Arne

Your patch has been applied to the master branch.

commit 68e0b9db253ff0437047d6a5377eeec6002873f8

Author: Steffan Karger
Date:   Sun Oct 7 12:00:32 2018 +0200

     Fix use-after-free in tls_ctx_use_management_external_key

     Signed-off-by: Steffan Karger <[email protected]...>
     Acked-by: Arne Schwabe <[email protected]...>
     Message-Id: <[email protected]...>
     URL: https://www.mail-archive.com/search?l=mid&[email protected]...
     Signed-off-by: Gert Doering <[email protected]...>

--
kind regards,

Gert Doering