Commit a93ff742 authored by Denis Arefev's avatar Denis Arefev Committed by Steve French
Browse files

ksmbd: Prevent integer overflow in calculation of deadtime 



The user can set any value for 'deadtime'. This affects the arithmetic
expression 'req->deadtime * SMB_ECHO_INTERVAL', which is subject to
overflow. The added check makes the server behavior more predictable.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 0626e664 ("cifsd: add server handler for central processing and tranport layers")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDenis Arefev <arefev@swemel.ru>
Acked-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent b37f2f33

fs/smb/server/transport_ipc.c

+6 −1
Original line number Diff line number Diff line
@@ -310,7 +310,11 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req) 
	server_conf.signing = req->signing;

	server_conf.tcp_port = req->tcp_port;

	server_conf.ipc_timeout = req->ipc_timeout * HZ;

	server_conf.deadtime = req->deadtime * SMB_ECHO_INTERVAL;

	if (check_mul_overflow(req->deadtime, SMB_ECHO_INTERVAL,

					&server_conf.deadtime)) {

		ret = -EINVAL;

		goto out;

	}

	server_conf.share_fake_fscaps = req->share_fake_fscaps;

	ksmbd_init_domain(req->sub_auth);
@@ -337,6 +341,7 @@ static int ipc_server_config_on_startup(struct ksmbd_startup_request *req) 
	server_conf.bind_interfaces_only = req->bind_interfaces_only;

	ret |= ksmbd_tcp_set_interfaces(KSMBD_STARTUP_CONFIG_INTERFACES(req),

					req->ifc_list_sz);

out:

	if (ret) {

		pr_err("Server configuration error: %s %s %s\n",

		       req->netbios_name, req->server_string,