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>
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index bd89285..51464d1 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -214,6 +214,7 @@
int register_jprobe(struct jprobe *p);
void unregister_jprobe(struct jprobe *p);
void jprobe_return(void);
+unsigned long arch_deref_entry_point(void *);
int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp);