diff options
| -rw-r--r-- | fs/smb/client/smb2pdu.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index cb61051f9af3..995fcdd30681 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -1713,17 +1713,30 @@ SMB2_auth_kerberos(struct SMB2_sess_data *sess_data) is_binding = (ses->ses_status == SES_GOOD); spin_unlock(&ses->ses_lock); + /* + * Per MS-SMB2 3.2.5.3, Session.SessionKey is the first 16 bytes of the + * GSS cryptographic key, right-padded with zero bytes if shorter. + * Allocate at least SMB2_NTLMV2_SESSKEY_SIZE bytes (zeroed) so the KDF + * input buffer is always valid for HMAC-SHA256 even with deprecated + * Kerberos enctypes that return a short session key. + */ + if (unlikely(msg->sesskey_len < SMB2_NTLMV2_SESSKEY_SIZE)) + cifs_dbg(VFS, + "short GSS session key (%u bytes); zero-padding per MS-SMB2 3.2.5.3\n", + msg->sesskey_len); + kfree_sensitive(ses->auth_key.response); - ses->auth_key.response = kmemdup(msg->data, - msg->sesskey_len, - GFP_KERNEL); + ses->auth_key.len = max_t(unsigned int, msg->sesskey_len, + SMB2_NTLMV2_SESSKEY_SIZE); + ses->auth_key.response = kzalloc(ses->auth_key.len, GFP_KERNEL); if (!ses->auth_key.response) { cifs_dbg(VFS, "%s: can't allocate (%u bytes) memory\n", - __func__, msg->sesskey_len); + __func__, ses->auth_key.len); + ses->auth_key.len = 0; rc = -ENOMEM; goto out_put_spnego_key; } - ses->auth_key.len = msg->sesskey_len; + memcpy(ses->auth_key.response, msg->data, msg->sesskey_len); sess_data->iov[1].iov_base = msg->data + msg->sesskey_len; sess_data->iov[1].iov_len = msg->secblob_len; |