From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C127219007D; Wed, 7 May 2025 18:46:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746643609; cv=none; b=MH/8gxfIc/PokFrzX7uZMts5og4D1h9r/MFzSjqcSoBscTSZgALf2jb1wsAnDbyMva7FvSFXvGxh5yhkBivDhhl117wfXNlyUuiK2wSypKSsPPecNb5bR7JgI8b0Qr0BR+wq4aAbU9DUWAKwBrmacixISBtY0cQRpS9I1Kk73Kg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746643609; c=relaxed/simple; bh=AsB23T4UufhKBxKplbKOKBFNU+G7B2YagUQTBcpPEug=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SlScpRQLRcdJkFrinOnFEMAiSGVyvqmVj7Tmk1HhFSPIv8ssIk/NVNxIhfLJEQspq5Y6kJ5JXp8SFIJt55CW1jOsxX+Ad/T3ihAxWDy228Nghbgkh8w/K/pYz2TqVJNmtuubrxTUc06FCp3iNNdfqCiGJpmWLMS0jSHBk6o3Cb8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=m91sS6Ra; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="m91sS6Ra" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 408E7C4CEE2; Wed, 7 May 2025 18:46:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1746643609; bh=AsB23T4UufhKBxKplbKOKBFNU+G7B2YagUQTBcpPEug=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m91sS6Rao7QwRf2ILQ/87dT7gStAOiXcCXaOTQ2ZJkMoj9KIrNRFF3iZpYAFZzcZa ZLouktU45NTVssa6dZCg7LXCzpUkcsy0alD95cWkwUgtWvQHQhj7rRpkkrYu9TbDBQ UNGrWbc3WE/dgn/VtyMCIK/KsWFdnUWkU1luhZx4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sean Heelan , Namjae Jeon , Steve French Subject: [PATCH 6.1 19/97] ksmbd: fix use-after-free in kerberos authentication Date: Wed, 7 May 2025 20:38:54 +0200 Message-ID: <20250507183807.755950373@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250507183806.987408728@linuxfoundation.org> References: <20250507183806.987408728@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Heelan 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 Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/auth.c | 14 +++++++++++++- fs/smb/server/smb2pdu.c | 5 ----- 2 files changed, 13 insertions(+), 6 deletions(-) --- a/fs/smb/server/auth.c +++ b/fs/smb/server/auth.c @@ -544,7 +544,19 @@ int ksmbd_krb5_authenticate(struct ksmbd 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, --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -1615,11 +1615,6 @@ static int krb5_authenticate(struct ksmb 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) {