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: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Cc: stable@vger.kernel.org Signed-off-by: Denis Arefev arefev@swemel.ru --- fs/smb/server/transport_ipc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/smb/server/transport_ipc.c b/fs/smb/server/transport_ipc.c index 3f185ae60dc5..2a3e2b0ce557 100644 --- a/fs/smb/server/transport_ipc.c +++ b/fs/smb/server/transport_ipc.c @@ -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,