diff options
| author | Sean Heelan <seanheelan@gmail.com> | 2025-04-19 19:59:28 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-09 09:50:35 +0200 |
| commit | e18c616718018dfc440e4a2d2b94e28fe91b1861 (patch) | |
| tree | 67023c957b8df91159afb155d03daecbf171a40d /fs/smb/server/auth.c | |
| parent | 8fb3b6c85b7e3127161623586b62abcc366caa20 (diff) | |
ksmbd: fix use-after-free in kerberos authentication
commit e86e9134e1d1c90a960dd57f59ce574d27b9a124 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/smb/server/auth.c')
| -rw-r--r-- | fs/smb/server/auth.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/smb/server/auth.c b/fs/smb/server/auth.c index 83caa38497493..b3d121052408c 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, |