From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936038AbeBLOpQ (ORCPT ); Mon, 12 Feb 2018 09:45:16 -0500 Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:46633 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754451AbeBLOpE (ORCPT ); Mon, 12 Feb 2018 09:45:04 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04452;MF=zhang.jia@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0Sy3mxO._1518446695; From: Jia Zhang To: tglx@linutronix.de, jolsa@redhat.com, mingo@redhat.com, hpa@zytor.com Cc: x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] /proc/kcore: Fix SMAP violation when dumping vsyscall user page Date: Mon, 12 Feb 2018 22:44:53 +0800 Message-Id: <1518446694-21124-2-git-send-email-zhang.jia@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1518446694-21124-1-git-send-email-zhang.jia@linux.alibaba.com> References: <1518446694-21124-1-git-send-email-zhang.jia@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The commit df04abfd181a ("fs/proc/kcore.c: Add bounce buffer for ktext data") introduces a bounce buffer to work around CONFIG_HARDENED_USERCOPY=y. However, accessing vsyscall user page will cause SMAP violation in this way. In order to fix this issue, simply replace memcpy() with copy_from_user() may work, but using 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 --- arch/x86/mm/init_64.c | 2 +- fs/proc/kcore.c | 4 ++++ include/linux/kcore.h | 1 + 3 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 1ab42c8..14cd7f8 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1194,7 +1194,7 @@ void __init mem_init(void) /* Register memory areas for /proc/kcore */ kclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR, - PAGE_SIZE, KCORE_OTHER); + PAGE_SIZE, KCORE_USER); mem_init_print_info(NULL); } diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index e8a93bc..7d8fa05 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -510,6 +510,10 @@ static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff) /* 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, }; -- 1.8.3.1