From 90ec5e89e393c76e19afc845d8f88a5dc8315919 Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" Date: Wed, 22 Feb 2017 19:23:37 +0530 Subject: kretprobes: Ensure probe location is at function entry kretprobes can be registered by specifying an absolute address or by specifying offset to a symbol. However, we need to ensure this falls at function entry so as to be able to determine the return address. Validate the same during kretprobe registration. By default, there should not be any offset from a function entry, as determined through a kallsyms_lookup(). Introduce arch_function_offset_within_entry() as a way for architectures to override this. Signed-off-by: Naveen N. Rao Acked-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Michael Ellerman Cc: Steven Rostedt Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/f1583bc4839a3862cfc2acefcc56f9c8837fa2ba.1487770934.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- kernel/kprobes.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 699c5bc51a92..448759d4a263 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1875,12 +1875,25 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) } NOKPROBE_SYMBOL(pre_handler_kretprobe); +bool __weak arch_function_offset_within_entry(unsigned long offset) +{ + return !offset; +} + int register_kretprobe(struct kretprobe *rp) { int ret = 0; struct kretprobe_instance *inst; int i; void *addr; + unsigned long offset; + + addr = kprobe_addr(&rp->kp); + if (!kallsyms_lookup_size_offset((unsigned long)addr, NULL, &offset)) + return -EINVAL; + + if (!arch_function_offset_within_entry(offset)) + return -EINVAL; if (kretprobe_blacklist_size) { addr = kprobe_addr(&rp->kp); -- cgit v1.2.3-59-g8ed1b