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authorMichael Ellerman <michael@ellerman.id.au>2007-07-19 01:48:11 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-19 10:04:44 -0700
commit3d7e33825d8799115dd2495c9944badd3272a623 (patch)
tree869eeefa9dd88c622db199f636cd1785c6099947 /arch/ia64
parent9e367d859297b9377d65574f538cf52730e9eda8 (diff)
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>
Diffstat (limited to 'arch/ia64')
-rw-r--r--arch/ia64/kernel/kprobes.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 5bc46f15134..5dc98b5abcf 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -936,10 +936,15 @@ static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
return;
}
+unsigned long arch_deref_entry_point(void *entry)
+{
+ return ((struct fnptr *)entry)->ip;
+}
+
int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct jprobe *jp = container_of(p, struct jprobe, kp);
- unsigned long addr = ((struct fnptr *)(jp->entry))->ip;
+ unsigned long addr = arch_deref_entry_point(jp->entry);
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
struct param_bsp_cfm pa;
int bytes;