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| author | Michael Ellerman <michael@ellerman.id.au> | 2007-07-19 01:48:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-19 10:04:44 -0700 |
| commit | 3d7e33825d8799115dd2495c9944badd3272a623 (patch) | |
| tree | 869eeefa9dd88c622db199f636cd1785c6099947 /arch/powerpc | |
| parent | 9e367d859297b9377d65574f538cf52730e9eda8 (diff) | |
| download | linux-3d7e33825d8799115dd2495c9944badd3272a623.tar.gz linux-3d7e33825d8799115dd2495c9944badd3272a623.tar.bz2 linux-3d7e33825d8799115dd2495c9944badd3272a623.zip | |
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/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/kprobes.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 0c96611f02f4..440f5a87271f 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -492,6 +492,13 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, return ret; } +#ifdef CONFIG_PPC64 +unsigned long arch_deref_entry_point(void *entry) +{ + return (unsigned long)(((func_descr_t *)entry)->entry); +} +#endif + int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) { struct jprobe *jp = container_of(p, struct jprobe, kp); @@ -500,11 +507,9 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); /* setup return addr to the jprobe handler routine */ + regs->nip = arch_deref_entry_point(jp->entry); #ifdef CONFIG_PPC64 - regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry); regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc); -#else - regs->nip = (unsigned long)jp->entry; #endif return 1; |