From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760146AbcCDQ1S (ORCPT ); Fri, 4 Mar 2016 11:27:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56244 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759627AbcCDQ1O (ORCPT ); Fri, 4 Mar 2016 11:27:14 -0500 From: Baoquan He To: linux-kernel@vger.kernel.org Cc: yinghai@kernel.org, keescook@chromium.org, hpa@zytor.com, vgoyal@redhat.com, mingo@redhat.com, bp@alien8.de, luto@kernel.org, lasse.collin@tukaani.org, akpm@linux-foundation.org, dyoung@redhat.com Subject: [PATCH v3 11/19] x86, boot: Add checking for memcpy Date: Sat, 5 Mar 2016 00:25:09 +0800 Message-Id: <1457108717-12191-12-git-send-email-bhe@redhat.com> In-Reply-To: <1457108717-12191-1-git-send-email-bhe@redhat.com> References: <1457108717-12191-1-git-send-email-bhe@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Yinghai Lu parse_elf is using local memcpy to move section to running position. That memcpy actually only support no overlapping case or when dest < src. Add checking in memcpy to find out the wrong case for future use, at that time we will need to have backward memcpy for it. Also add comments in parse_elf about the fact. Signed-off-by: Yinghai Lu --- v2->v3: Add a declaration for error() since its declaration is in misc.h. But it's not included in compressed/string.c. arch/x86/boot/compressed/misc.c | 14 +++++++------- arch/x86/boot/compressed/misc.h | 2 ++ arch/x86/boot/compressed/string.c | 29 +++++++++++++++++++++++++++-- 3 files changed, 36 insertions(+), 9 deletions(-) diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index dd7ed8a..4b2cd0c 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -114,9 +114,6 @@ #undef memset #define memzero(s, n) memset((s), 0, (n)) - -static void error(char *m); - /* * This is set up by the setup-routine at boot-time */ @@ -243,7 +240,7 @@ void __puthex(unsigned long value) } } -static void error(char *x) +void error(char *x) { error_putstr("\n\n"); error_putstr(x); @@ -378,9 +375,12 @@ static void parse_elf(void *output) #else dest = (void *)(phdr->p_paddr); #endif - memcpy(dest, - output + phdr->p_offset, - phdr->p_filesz); + /* + * simple version memcpy only can work when dest is + * smaller than src or no overlapping. + * Here dest is smaller than src always. + */ + memcpy(dest, output + phdr->p_offset, phdr->p_filesz); break; default: /* Ignore other PT_* */ break; } diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 11736a6..39d0e9a 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -38,6 +38,8 @@ void __puthex(unsigned long value); #define error_putstr(__x) __putstr(__x) #define error_puthex(__x) __puthex(__x) +void error(char *x); + #ifdef CONFIG_X86_VERBOSE_BOOTUP #define debug_putstr(__x) __putstr(__x) diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c index 00e788b..3a935d0 100644 --- a/arch/x86/boot/compressed/string.c +++ b/arch/x86/boot/compressed/string.c @@ -1,7 +1,7 @@ #include "../string.c" #ifdef CONFIG_X86_32 -void *memcpy(void *dest, const void *src, size_t n) +void *__memcpy(void *dest, const void *src, size_t n) { int d0, d1, d2; asm volatile( @@ -15,7 +15,7 @@ void *memcpy(void *dest, const void *src, size_t n) return dest; } #else -void *memcpy(void *dest, const void *src, size_t n) +void *__memcpy(void *dest, const void *src, size_t n) { long d0, d1, d2; asm volatile( @@ -30,6 +30,31 @@ void *memcpy(void *dest, const void *src, size_t n) } #endif +extern void error(char *x); +void *memcpy(void *dest, const void *src, size_t n) +{ + unsigned long start_dest, end_dest; + unsigned long start_src, end_src; + unsigned long max_start, min_end; + + if (dest < src) + return __memcpy(dest, src, n); + + start_dest = (unsigned long)dest; + end_dest = (unsigned long)dest + n; + start_src = (unsigned long)src; + end_src = (unsigned long)src + n; + max_start = (start_dest > start_src) ? start_dest : start_src; + min_end = (end_dest < end_src) ? end_dest : end_src; + + if (max_start >= min_end) + return __memcpy(dest, src, n); + + error("memcpy does not support overlapping with dest > src!\n"); + + return dest; +} + void *memset(void *s, int c, size_t n) { int i; -- 2.5.0