jprobes: make jprobes a little safer for users
authorMichael Ellerman <michael@ellerman.id.au>
Thu, 19 Jul 2007 08:48:11 +0000 (01:48 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Thu, 19 Jul 2007 17:04:44 +0000 (10:04 -0700)
commit3d7e33825d8799115dd2495c9944badd3272a623
tree869eeefa9dd88c622db199f636cd1785c6099947
parent9e367d859297b9377d65574f538cf52730e9eda8
jprobes: make jprobes a little safer for users

I realise jprobes are a razor-blades-included type of interface, but that
doesn't mean we can't try and make them safer to use.  This guy I know once
wrote code like this:

struct jprobe jp = { .kp.symbol_name = "foo", .entry = "jprobe_foo" };

And then his kernel exploded. Oops.

This patch adds an arch hook, arch_deref_entry_point() (I don't like it
either) which takes the void * in a struct jprobe, and gives back the text
address that it represents.

We can then use that in register_jprobe() to check that the entry point we're
passed is actually in the kernel text, rather than just some random value.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/ia64/kernel/kprobes.c
arch/powerpc/kernel/kprobes.c
include/linux/kprobes.h
kernel/kprobes.c