From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from NAM01-BN3-obe.outbound.protection.outlook.com (mail-bn3nam01on0118.outbound.protection.outlook.com [104.47.33.118]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3zv1985DL6zDrL8 for ; Sun, 4 Mar 2018 09:31:05 +1100 (AEDT) From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: "Naveen N. Rao" , Ananth N Mavinakayanahalli , Michael Ellerman , Steven Rostedt , "linuxppc-dev@lists.ozlabs.org" , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH AUTOSEL for 4.9 005/219] kretprobes: Ensure probe location is at function entry Date: Sat, 3 Mar 2018 22:27:58 +0000 Message-ID: <20180303222716.26640-5-alexander.levin@microsoft.com> References: <20180303222716.26640-1-alexander.levin@microsoft.com> In-Reply-To: <20180303222716.26640-1-alexander.levin@microsoft.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Naveen N. Rao" [ Upstream commit 90ec5e89e393c76e19afc845d8f88a5dc8315919 ] 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.148= 7770934.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- include/linux/kprobes.h | 1 + kernel/kprobes.c | 13 +++++++++++++ 2 files changed, 14 insertions(+) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index e23392517db9..56a998f34bdd 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -266,6 +266,7 @@ extern int arch_init_kprobes(void); extern void show_registers(struct pt_regs *regs); extern void kprobes_inc_nmissed_count(struct kprobe *p); extern bool arch_within_kprobe_blacklist(unsigned long addr); +extern bool arch_function_offset_within_entry(unsigned long offset); =20 extern bool within_kprobe_blacklist(unsigned long addr); =20 diff --git a/kernel/kprobes.c b/kernel/kprobes.c index a1a07cf1101f..2ede39e4227f 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1834,12 +1834,25 @@ static int pre_handler_kretprobe(struct kprobe *p, = struct pt_regs *regs) } NOKPROBE_SYMBOL(pre_handler_kretprobe); =20 +bool __weak arch_function_offset_within_entry(unsigned long offset) +{ + return !offset; +} + int register_kretprobe(struct kretprobe *rp) { int ret =3D 0; struct kretprobe_instance *inst; int i; void *addr; + unsigned long offset; + + addr =3D 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; =20 if (kretprobe_blacklist_size) { addr =3D kprobe_addr(&rp->kp); --=20 2.14.1