From fe56d5951f0b42fd3ff1cf42a96d07f06f9692bc Mon Sep 17 00:00:00 2001 From: Matt Caswell Date: Mon, 30 Mar 2020 14:15:06 +0100 Subject: [PATCH] Don't double free a DH object Having created a DH object and assigned it to an EVP_PKEY - we should not free both the EVP_PKEY and the original DH. This will lead to a double free occurring. This issue was discovered and reported by GitHub Security Lab team member Agustin Gianni. Reviewed-by: Shane Lontis Reviewed-by: Tomas Mraz (Merged from https://github.com/openssl/openssl/pull/11441) --- ssl/statem/statem_clnt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c index 534902f9b9..4c4e6cb209 100644 --- a/ssl/statem/statem_clnt.c +++ b/ssl/statem/statem_clnt.c @@ -2152,9 +2152,10 @@ static int tls_process_ske_dhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey) ERR_R_EVP_LIB); goto err; } + dh = NULL; if (!ssl_security(s, SSL_SECOP_TMP_DH, EVP_PKEY_security_bits(peer_tmp), - 0, dh)) { + 0, EVP_PKEY_get0_DH(peer_tmp))) { SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PROCESS_SKE_DHE, SSL_R_DH_KEY_TOO_SMALL); goto err; -- 2.25.1