From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934017AbeBMJI0 (ORCPT ); Tue, 13 Feb 2018 04:08:26 -0500 Received: from terminus.zytor.com ([198.137.202.136]:34045 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933897AbeBMJIF (ORCPT ); Tue, 13 Feb 2018 04:08:05 -0500 Date: Tue, 13 Feb 2018 01:07:42 -0800 From: tip-bot for Jia Zhang Message-ID: Cc: torvalds@linux-foundation.org, hpa@zytor.com, linux-kernel@vger.kernel.org, jolsa@kernel.org, mingo@kernel.org, zhang.jia@linux.alibaba.com, tglx@linutronix.de, peterz@infradead.org, viro@zeniv.linux.org.uk Reply-To: peterz@infradead.org, viro@zeniv.linux.org.uk, tglx@linutronix.de, zhang.jia@linux.alibaba.com, mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, jolsa@kernel.org, torvalds@linux-foundation.org In-Reply-To: <1518446694-21124-2-git-send-email-zhang.jia@linux.alibaba.com> References: <1518446694-21124-2-git-send-email-zhang.jia@linux.alibaba.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page Git-Commit-ID: 595dd46ebfc10be041a365d0a3fa99df50b6ba73 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 595dd46ebfc10be041a365d0a3fa99df50b6ba73 Gitweb: https://git.kernel.org/tip/595dd46ebfc10be041a365d0a3fa99df50b6ba73 Author: Jia Zhang AuthorDate: Mon, 12 Feb 2018 22:44:53 +0800 Committer: Ingo Molnar CommitDate: Tue, 13 Feb 2018 09:15:58 +0100 vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page Commit: df04abfd181a ("fs/proc/kcore.c: Add bounce buffer for ktext data") ... introduced a bounce buffer to work around CONFIG_HARDENED_USERCOPY=y. However, accessing the vsyscall user page will cause an SMAP fault. Replace memcpy() with copy_from_user() to fix this bug works, but adding a common way to handle this sort of user page may be useful for future. Currently, only vsyscall page requires KCORE_USER. Signed-off-by: Jia Zhang Reviewed-by: Jiri Olsa Cc: Al Viro Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: jolsa@redhat.com Link: http://lkml.kernel.org/r/1518446694-21124-2-git-send-email-zhang.jia@linux.alibaba.com Signed-off-by: Ingo Molnar --- arch/x86/mm/init_64.c | 3 +-- fs/proc/kcore.c | 4 ++++ include/linux/kcore.h | 1 + 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 1ab42c8..6aa33d1 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1193,8 +1193,7 @@ void __init mem_init(void) register_page_bootmem_info(); /* Register memory areas for /proc/kcore */ - kclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR, - PAGE_SIZE, KCORE_OTHER); + kclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR, PAGE_SIZE, KCORE_USER); mem_init_print_info(NULL); } diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index e8a93bc..d1e8276 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -510,6 +510,10 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) /* we have to zero-fill user buffer even if no read */ if (copy_to_user(buffer, buf, tsz)) return -EFAULT; + } else if (m->type == KCORE_USER) { + /* User page is handled prior to normal kernel page: */ + if (copy_to_user(buffer, (char *)start, tsz)) + return -EFAULT; } else { if (kern_addr_valid(start)) { /* diff --git a/include/linux/kcore.h b/include/linux/kcore.h index 7ff25a8..80db19d 100644 --- a/include/linux/kcore.h +++ b/include/linux/kcore.h @@ -10,6 +10,7 @@ enum kcore_type { KCORE_VMALLOC, KCORE_RAM, KCORE_VMEMMAP, + KCORE_USER, KCORE_OTHER, };