commit 9f36e2c448007b54851e7e4fa48da97d1477a175
author Kees Cook <kees.cook@canonical.com> Tue Mar 22 16:34:22 2011 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> Tue Mar 22 17:44:12 2011 -0700
tree 2fa0ad88c75184dc79b28c287c853e97f779bf1f
parent fe3d8ad31cf51b062bbb8a9609eeb1d0c41a7f30

printk: use %pK for /proc/kallsyms and /proc/modules

In an effort to reduce kernel address leaks that might be used to help
target kernel privilege escalation exploits, this patch uses %pK when
displaying addresses in /proc/kallsyms, /proc/modules, and
/sys/module/*/sections/*.

Note that this changes %x to %p, so some legitimately 0 values in
/proc/kallsyms would have changed from 00000000 to "(null)".  To avoid
this, "(null)" is not used when using the "K" format.  Anything that was
already successfully parsing "(null)" in addition to full hex digits
should have no problem with this change.  (Thanks to Joe Perches for the
suggestion.) Due to the %x to %p, "void *" casts are needed since these
addresses are already "unsigned long" everywhere internally, due to their
starting life as ELF section offsets.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Cc: Eugene Teo <eugene@redhat.com>
Cc: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>