tree 4b90b18cb60d1db94325675886b74f0aa0bf346f
parent 078d396598401dbaa88d5f95ec45579f9d3dce0e
author Jeff Garzik <jeff@garzik.org> 1161069039 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1161098329 -0700

[PATCH] ISDN: fix drivers, by handling errors thrown by ->readstat()

This is a particularly ugly on-failure bug, possibly security, since the
lack of error handling here is covering up another class of bug: failure to
handle copy_to_user() return values.

The I4L API function ->readstat() returns an integer, and by looking at
several existing driver implementations, it is clear that a negative return
value was meant to indicate an error.

Given that several drivers already return a negative value indicating an
errno-style error, the current code would blindly accept that [negative]
value as a valid amount of bytes read.  Obvious damage ensues.

Correcting ->readstat() handling to properly notice errors fixes the
existing code to work correctly on error, and enables future patches to
more easily indicate errors during operation.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Cc: Karsten Keil <kkeil@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>