diff options
| author | Sean Heelan <seanheelan@gmail.com> | 2025-04-19 19:59:28 +0100 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2025-04-25 18:22:01 -0500 |
| commit | e86e9134e1d1c90a960dd57f59ce574d27b9a124 (patch) | |
| tree | 1b2ffb54bb6f6dad6a2917b7c59c3acc03fb62e0 /fs | |
| parent | a1f46c99d9ea411f9bf30025b912d881d36fc709 (diff) | |
ksmbd: fix use-after-free in kerberos authentication
Setting sess->user = NULL was introduced to fix the dangling pointer
created by ksmbd_free_user. However, it is possible another thread could
be operating on the session and make use of sess->user after it has been
passed to ksmbd_free_user but before sess->user is set to NULL.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Heelan <seanheelan@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/smb/server/auth.c | 14 | ||||
| -rw-r--r-- | fs/smb/server/smb2pdu.c | 5 |
2 files changed, 13 insertions, 6 deletions
diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c index 83caa3849749..b3d121052408 100644 --- a/fs/smb/server/auth.c +++ b/fs/smb/server/auth.c @@ -550,7 +550,19 @@ int ksmbd_krb5_authenticate(struct ksmbd_session *sess, char *in_blob, retval = -ENOMEM; goto out; } - sess->user = user; + + if (!sess->user) { + /* First successful authentication */ + sess->user = user; + } else { + if (!ksmbd_compare_user(sess->user, user)) { + ksmbd_debug(AUTH, "different user tried to reuse session\n"); + retval = -EPERM; + ksmbd_free_user(user); + goto out; + } + ksmbd_free_user(user); + } memcpy(sess->sess_key, resp->payload, resp->session_key_len); memcpy(out_blob, resp->payload + resp->session_key_len, diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 372021b3f263..acc05657cfc7 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -1607,11 +1607,6 @@ static int krb5_authenticate(struct ksmbd_work *work, if (prev_sess_id && prev_sess_id != sess->id) destroy_previous_session(conn, sess->user, prev_sess_id); - if (sess->state == SMB2_SESSION_VALID) { - ksmbd_free_user(sess->user); - sess->user = NULL; - } - retval = ksmbd_krb5_authenticate(sess, in_blob, in_len, out_blob, &out_len); if (retval) { |