tree d99c06b802df92b1618fe67fe3a6a5e811b7b43b
parent 833c95456a70826d1384883b73fd23aff24d366f
author Ben Hutchings <ben@decadent.org.uk> 1409038484 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1411538115 -0700

drivers/base: Fix length checks in create_syslog_header()/dev_vprintk_emit()

snprintf() returns the number of bytes that could have been written
(excluding the null), not the actual number of bytes written.  Given a
long enough subsystem or device name, these functions will advance
beyond the end of the on-stack buffer in dev_vprintk_exit(), resulting
in an information leak or stack corruption.  I don't know whether such
a long name is currently possible.

In case snprintf() returns a value >= the buffer size, do not add
structured logging information.  Also WARN if this happens, so we can
fix the driver or increase the buffer size.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>