Re: [PATCH] isdn/i4l: check the message proto does not change across fetches

2017-09-19 Thread David Miller
From: Meng Xu Date: Tue, 19 Sep 2017 14:52:58 -0400 > In isdn_ppp_write(), the header (i.e., protobuf) of the buffer is fetched > twice from userspace. The first fetch is used to peek at the protocol > of the message and reset the huptimer if necessary; while the second > fetch copies in the whol

[PATCH] isdn/i4l: check the message proto does not change across fetches

2017-09-19 Thread Meng Xu
In isdn_ppp_write(), the header (i.e., protobuf) of the buffer is fetched twice from userspace. The first fetch is used to peek at the protocol of the message and reset the huptimer if necessary; while the second fetch copies in the whole buffer. However, given that buf resides in userspace memory,