6.1-stable review patch. If anyone has any objections, please let me know.
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From: Namjae Jeon linkinjeon@kernel.org
commit 7ac5b66acafcc9292fb935d7e03790f2b8b2dc0e upstream.
If client set ->PreviousSessionId on kerberos session setup stage, NULL pointer dereference error will happen. Since sess->user is not set yet, It can pass the user argument as NULL to destroy_previous_session. sess->user will be set in ksmbd_krb5_authenticate(). So this patch move calling destroy_previous_session() after ksmbd_krb5_authenticate().
Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-27391 Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/smb/server/smb2pdu.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -1610,17 +1610,18 @@ static int krb5_authenticate(struct ksmb out_len = work->response_sz - (le16_to_cpu(rsp->SecurityBufferOffset) + 4);
- /* Check previous session */ - prev_sess_id = le64_to_cpu(req->PreviousSessionId); - if (prev_sess_id && prev_sess_id != sess->id) - destroy_previous_session(conn, sess->user, prev_sess_id); - retval = ksmbd_krb5_authenticate(sess, in_blob, in_len, out_blob, &out_len); if (retval) { ksmbd_debug(SMB, "krb5 authentication failed\n"); return -EINVAL; } + + /* Check previous session */ + prev_sess_id = le64_to_cpu(req->PreviousSessionId); + if (prev_sess_id && prev_sess_id != sess->id) + destroy_previous_session(conn, sess->user, prev_sess_id); + rsp->SecurityBufferLength = cpu_to_le16(out_len);
if ((conn->sign || server_conf.enforced_signing) ||