android_kernel_oneplus_msm8998/drivers/isdn/i4l
Meng Xu d9cb4dc022 isdn/i4l: fetch the ppp_write buffer in one shot
[ Upstream commit 02388bf87f72e1d47174cd8f81c34443920eb5a0 ]

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, a user process can race to change its memory content
across fetches. By doing so, we can either avoid resetting the huptimer
for any type of packets (by first setting proto to PPP_LCP and later
change to the actual type) or force resetting the huptimer for LCP
packets.

This patch changes this double-fetch behavior into two single fetches
decided by condition (lp->isdn_device < 0 || lp->isdn_channel <0).
A more detailed discussion can be found at
https://marc.info/?l=linux-kernel&m=150586376926123&w=2

Signed-off-by: Meng Xu <mengxu.gatech@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-21 17:09:02 +02:00
..
isdn_audio.c
isdn_audio.h
isdn_bsdcomp.c
isdn_common.c isdn/i4l: fix buffer overflow 2017-08-06 19:19:41 -07:00
isdn_common.h
isdn_concap.c
isdn_concap.h
isdn_net.c isdn/i4l: fix buffer overflow 2017-08-06 19:19:41 -07:00
isdn_net.h
isdn_ppp.c isdn/i4l: fetch the ppp_write buffer in one shot 2017-10-21 17:09:02 +02:00
isdn_ppp.h
isdn_tty.c tty: Remove tty_wait_until_sent_from_close() 2015-10-17 21:11:29 -07:00
isdn_tty.h
isdn_ttyfax.c
isdn_ttyfax.h
isdn_v110.c
isdn_v110.h
isdn_x25iface.c
isdn_x25iface.h
isdnhdlc.c
Kconfig
Makefile