From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932186Ab2DTWxG (ORCPT ); Fri, 20 Apr 2012 18:53:06 -0400 Received: from outmail019.snc4.facebook.com ([66.220.144.153]:48871 "EHLO intmgw001.snc4.facebook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756376Ab2DTWw7 (ORCPT ); Fri, 20 Apr 2012 18:52:59 -0400 From: Arun Sharma To: linux-kernel@vger.kernel.org Cc: Arun Sharma , Linus Torvalds , Peter Zijlstra , Ingo Molnar Subject: [PATCH 3/4] perf, x86: Check if user fp is valid Date: Fri, 20 Apr 2012 15:41:35 -0700 Message-Id: <1334961696-19580-4-git-send-email-asharma@fb.com> X-Mailer: git-send-email 1.7.8.4 In-Reply-To: <1334961696-19580-1-git-send-email-asharma@fb.com> References: <1334961696-19580-1-git-send-email-asharma@fb.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Arun Sharma Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Ingo Molnar Cc: linux-kernel@vger.kernel.org --- arch/x86/include/asm/uaccess.h | 13 +++++++------ arch/x86/kernel/cpu/perf_event.c | 12 ++++++++++++ 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index e054459..997d59b 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -32,9 +32,9 @@ #define segment_eq(a, b) ((a).seg == (b).seg) -#define __addr_ok(addr) \ - ((unsigned long __force)(addr) < \ - (current_thread_info()->addr_limit.seg)) +#define __cur_addr_limit (current_thread_info()->addr_limit.seg) +#define __addr_ok(addr) \ + ((unsigned long __force)(addr) < __cur_addr_limit) /* * Test whether a block of memory is a valid user space address. @@ -46,14 +46,14 @@ * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... */ -#define __range_not_ok(addr, size) \ +#define __range_not_ok(addr, size, limit) \ ({ \ unsigned long flag, roksum; \ __chk_user_ptr(addr); \ asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ : "=&r" (flag), "=r" (roksum) \ : "1" (addr), "g" ((long)(size)), \ - "rm" (current_thread_info()->addr_limit.seg)); \ + "rm" (limit)); \ flag; \ }) @@ -76,7 +76,8 @@ * checks that the pointer is in the user space range - after calling * this function, memory access functions may still return -EFAULT. */ -#define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0)) +#define access_ok(type, addr, size) \ + (likely(__range_not_ok(addr, size, __cur_addr_limit) == 0)) /* * The exception table consists of pairs of addresses: the first is the diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 9f98636..3e4be2c 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1761,6 +1761,12 @@ perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs) dump_trace(NULL, regs, NULL, 0, &backtrace_ops, entry); } +static inline int +valid_user_frame(const void __user *fp, unsigned long size) +{ + return (__range_not_ok(fp, size, TASK_SIZE) == 0); +} + #ifdef CONFIG_COMPAT #include @@ -1785,6 +1791,9 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry) if (bytes != sizeof(frame)) break; + if (!valid_user_frame(fp, sizeof(frame))) + break; + perf_callchain_store(entry, frame.return_address); fp = compat_ptr(frame.next_frame); } @@ -1828,6 +1837,9 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) if (bytes != sizeof(frame)) break; + if (!valid_user_frame(fp, sizeof(frame))) + break; + perf_callchain_store(entry, frame.return_address); fp = frame.next_frame; } -- 1.7.8.4