cifs: ensure that uncached writes handle unmapped areas correctly

commit 5d81de8e8667da7135d3a32a964087c0faf5483f upstream.

It's possible for userland to pass down an iovec via writev() that has a
bogus user pointer in it. If that happens and we're doing an uncached
write, then we can end up getting less bytes than we expect from the
call to iov_iter_copy_from_user. This is CVE-2014-0069

cifs_iovec_write isn't set up to handle that situation however. It'll
blindly keep chugging through the page array and not filling those pages
with anything useful. Worse yet, we'll later end up with a negative
number in wdata->tailsz, which will confuse the sending routines and
cause an oops at the very least.

Fix this by having the copy phase of cifs_iovec_write stop copying data
in this situation and send the last write as a short one. At the same
time, we want to avoid sending a zero-length write to the server, so
break out of the loop and set rc to -EFAULT if that happens. This also
allows us to handle the case where no address in the iovec is valid.

[Note: Marking this for stable on v3.4+ kernels, but kernels as old as
       v2.6.38 may have a similar problem and may need similar fix]

Change-Id: If08b3f9db0f977e18e07d26b01293ae14a0401a3
Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rtl8187: fix regression on MIPS without coherent DMA

commit b6213e413a4e0c66548153516b074df14f9d08e0 upstream.

This patch fixes regression caused by commit a16dad77634 "MIPS: Fix
potencial corruption". That commit fixes one corruption scenario in
cost of adding another one, which actually start to cause crashes
on Yeeloong laptop when rtl8187 driver is used.

For correct DMA read operation on machines without DMA coherence, kernel
have to invalidate cache, such it will refill later with new data that
device wrote to memory, when that data is needed to process. We can only
invalidate full cache line. Hence when cache line includes both dma
buffer and some other data (written in cache, but not yet in main
memory), the other data can not hit memory due to invalidation. That
happen on rtl8187 where struct rtl8187_priv fields are located just
before and after small buffers that are passed to USB layer and DMA
is performed on them.

To fix the problem we align buffers and reserve space after them to make
them match cache line.

This patch does not resolve all possible MIPS problems entirely, for
that we have to assure that we always map cache aligned buffers for DMA,
what can be complex or even not possible. But patch fixes visible and
reproducible regression and seems other possible corruptions do not
happen in practice, since Yeeloong laptop works stable without rtl8187
driver.

Bug report:
https://bugzilla.kernel.org/show_bug.cgi?id=54391

Change-Id: I3a7b86dd624b25cfc56bef497b176f0f105de02c
Reported-by: Petr Pisar <petr.pisar@atlas.cz>
Bisected-by: Tom Li <biergaizi2009@gmail.com>
Reported-and-tested-by: Tom Li <biergaizi2009@gmail.com>
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Acked-by: Larry Finger <Larry.Finger@lwfinger.next>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rtlwifi: Fix incorrect return from rtl_ps_enable_nic()

commit 2e8c5e56b307271c2dab6f8bfd1d8a3822ca2390 upstream.

rtl_ps_enable_nic() is called from loops that will loop until this function returns true or a
maximum number of retries is performed.

hw_init() returns non-zero on error. In that situation return false to
restore the original design intent to retry hw init when it fails.

Change-Id: I3d004075304339cb7721776211d54db1b502f9e4
Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>