[lvc-project] [PATCH 5.10] cifs: fix potential memory leaks in session setup

[Denis Arefev]

From: Paulo Alcantara <pc at cjr.nz>

commit 2fe58d977ee05da5bb89ef5dc4f5bf2dc15db46f upstream.

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 at cjr.nz>
Signed-off-by: Steve French <stfrench at microsoft.com>
[Denis: minor fix to resolve merge conflict.]                                           
Signed-off-by: Denis Arefev <arefev at swemel.ru>                                    
---
Backport fix for CVE-2023-53008
Link: https://nvd.nist.gov/vuln/detail/CVE-2023-53008
---
 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 9daa256f69d4..c75bcdc987e0 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -371,6 +371,7 @@ 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 cf6fd138d8d5..d4e215674597 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -601,6 +601,7 @@ 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) {
@@ -1335,6 +1336,7 @@ 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 4197096e7fdb..15f9faa1e20a 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1360,6 +1360,7 @@ SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
 
 	/* keep session key if binding */
 	if (!ses->binding) {
+		kfree_sensitive(ses->auth_key.response);
 		ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
 						 GFP_KERNEL);
 		if (!ses->auth_key.response) {
-- 
2.43.0