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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Paulo Alcantara <pc@cjr.nz>, Steve French <stfrench@microsoft.com>,
        Sasha Levin <sashal@kernel.org>, sfrench@samba.org,
        linux-cifs@vger.kernel.org, samba-technical@lists.samba.org
Subject: [PATCH AUTOSEL 6.1 37/53] cifs: fix potential memory leaks in session setup
Date:   Mon, 16 Jan 2023 09:01:37 -0500
Message-Id: <20230116140154.114951-37-sashal@kernel.org>
In-Reply-To: <20230116140154.114951-1-sashal@kernel.org>
References: <20230116140154.114951-1-sashal@kernel.org>
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From: Paulo Alcantara <pc@cjr.nz>

[ Upstream commit 2fe58d977ee05da5bb89ef5dc4f5bf2dc15db46f ]

Make sure to free cifs_ses::auth_key.response before allocating it as
we might end up leaking memory in reconnect or mounting.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/cifsencrypt.c | 1 +
 fs/cifs/sess.c        | 2 ++
 fs/cifs/smb2pdu.c     | 1 +
 3 files changed, 4 insertions(+)

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 5db73c0f792a..cbc18b4a9cb2 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -278,6 +278,7 @@ build_avpair_blob(struct cifs_ses *ses, const struct nls_table *nls_cp)
 	 * ( for NTLMSSP_AV_NB_DOMAIN_NAME followed by NTLMSSP_AV_EOL ) +
 	 * unicode length of a netbios domain name
 	 */
+	kfree_sensitive(ses->auth_key.response);
 	ses->auth_key.len = size + 2 * dlen;
 	ses->auth_key.response = kzalloc(ses->auth_key.len, GFP_KERNEL);
 	if (!ses->auth_key.response) {
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 0b842a07e157..c47b254f0d1e 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -815,6 +815,7 @@ int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
 		return -EINVAL;
 	}
 	if (tilen) {
+		kfree_sensitive(ses->auth_key.response);
 		ses->auth_key.response = kmemdup(bcc_ptr + tioffset, tilen,
 						 GFP_KERNEL);
 		if (!ses->auth_key.response) {
@@ -1428,6 +1429,7 @@ sess_auth_kerberos(struct sess_data *sess_data)
 		goto out_put_spnego_key;
 	}
 
+	kfree_sensitive(ses->auth_key.response);
 	ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
 					 GFP_KERNEL);
 	if (!ses->auth_key.response) {
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index a5695748a89b..d5a0eb2c0a1d 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1450,6 +1450,7 @@ SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
 
 	/* keep session key if binding */
 	if (!is_binding) {
+		kfree_sensitive(ses->auth_key.response);
 		ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
 						 GFP_KERNEL);
 		if (!ses->auth_key.response) {
-- 
2.35.1