From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752496Ab3B1LCv (ORCPT ); Thu, 28 Feb 2013 06:02:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:6267 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751078Ab3B1LCu (ORCPT ); Thu, 28 Feb 2013 06:02:50 -0500 From: Anton Arapov To: Anton Arapov , Oleg Nesterov , Srikar Dronamraju Cc: LKML , Josh Stone , Frank Eigler , Peter Zijlstra , Ingo Molnar , Ananth N Mavinakayanahalli Subject: [RFC PATCH v3 2/6] uretprobes/x86: hijack return address Date: Thu, 28 Feb 2013 12:00:11 +0100 Message-Id: <1362049215-5780-3-git-send-email-anton@redhat.com> In-Reply-To: <1362049215-5780-1-git-send-email-anton@redhat.com> References: <1362049215-5780-1-git-send-email-anton@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org hijack the return address and replace it with a "trampoline" v2: - remove ->doomed flag, kill task immediately Signed-off-by: Anton Arapov --- arch/x86/include/asm/uprobes.h | 1 + arch/x86/kernel/uprobes.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 8ff8be7..c353555 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -55,4 +55,5 @@ extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long rp_trampoline_vaddr, struct pt_regs *regs); #endif /* _ASM_UPROBES_H */ diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 0ba4cfb..85e2153 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -697,3 +697,32 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) send_sig(SIGTRAP, current, 0); return ret; } + +extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long + rp_trampoline_vaddr, struct pt_regs *regs) +{ + int rasize, ncopied; + unsigned long orig_ret_vaddr = 0; /* clear high bits for 32-bit apps */ + + rasize = is_ia32_task() ? 4 : 8; + ncopied = copy_from_user(&orig_ret_vaddr, (void __user *)regs->sp, rasize); + if (unlikely(ncopied)) + return 0; + + /* check whether address has been already hijacked */ + if (orig_ret_vaddr == rp_trampoline_vaddr) + return orig_ret_vaddr; + + ncopied = copy_to_user((void __user *)regs->sp, &rp_trampoline_vaddr, rasize); + if (unlikely(ncopied)) { + if (ncopied != rasize) { + printk(KERN_ERR "uretprobe: return address clobbered: " + "pid=%d, %%sp=%#lx, %%ip=%#lx\n", + current->pid, regs->sp, regs->ip); + /* kill task immediately */ + send_sig(SIGSEGV, current, 0); + } + } + + return orig_ret_vaddr; +} -- 1.8.1.2