linux-kernel - [PATCH 4.14 297/496] ARM: 8748/1: mm: Define vdso_start, vdso

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180528100332.342431607@linuxfoundation.org>
Date:   Mon, 28 May 2018 12:01:22 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Kees Cook <keescook@...omium.org>,
        Jinbum Park <jinb.park7@...il.com>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.14 297/496] ARM: 8748/1: mm: Define vdso_start, vdso_end as array

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jinbum Park <jinb.park7@...il.com>

[ Upstream commit 73b9160d0dfe44dfdaffd6465dc1224c38a4a73c ]

Define vdso_start, vdso_end as array to avoid compile-time analysis error
for the case of built with CONFIG_FORTIFY_SOURCE.

and, since vdso_start, vdso_end are used in vdso.c only,
move extern-declaration from vdso.h to vdso.c.

If kernel is built with CONFIG_FORTIFY_SOURCE,
compile-time error happens at this code.
- if (memcmp(&vdso_start, "177ELF", 4))

The size of "&vdso_start" is recognized as 1 byte, but n is 4,
So that compile-time error is reported.

Acked-by: Kees Cook <keescook@...omium.org>
Signed-off-by: Jinbum Park <jinb.park7@...il.com>
Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/arm/include/asm/vdso.h |    2 --
 arch/arm/kernel/vdso.c      |   12 +++++++-----
 2 files changed, 7 insertions(+), 7 deletions(-)

--- a/arch/arm/include/asm/vdso.h
+++ b/arch/arm/include/asm/vdso.h
@@ -12,8 +12,6 @@ struct mm_struct;
 
 void arm_install_vdso(struct mm_struct *mm, unsigned long addr);
 
-extern char vdso_start, vdso_end;
-
 extern unsigned int vdso_total_pages;
 
 #else /* CONFIG_VDSO */
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -39,6 +39,8 @@
 
 static struct page **vdso_text_pagelist;
 
+extern char vdso_start[], vdso_end[];
+
 /* Total number of pages needed for the data and text portions of the VDSO. */
 unsigned int vdso_total_pages __ro_after_init;
 
@@ -197,13 +199,13 @@ static int __init vdso_init(void)
 	unsigned int text_pages;
 	int i;
 
-	if (memcmp(&vdso_start, "\177ELF", 4)) {
+	if (memcmp(vdso_start, "\177ELF", 4)) {
 		pr_err("VDSO is not a valid ELF object!\n");
 		return -ENOEXEC;
 	}
 
-	text_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
-	pr_debug("vdso: %i text pages at base %p\n", text_pages, &vdso_start);
+	text_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
+	pr_debug("vdso: %i text pages at base %p\n", text_pages, vdso_start);
 
 	/* Allocate the VDSO text pagelist */
 	vdso_text_pagelist = kcalloc(text_pages, sizeof(struct page *),
@@ -218,7 +220,7 @@ static int __init vdso_init(void)
 	for (i = 0; i < text_pages; i++) {
 		struct page *page;
 
-		page = virt_to_page(&vdso_start + i * PAGE_SIZE);
+		page = virt_to_page(vdso_start + i * PAGE_SIZE);
 		vdso_text_pagelist[i] = page;
 	}
 
@@ -229,7 +231,7 @@ static int __init vdso_init(void)
 
 	cntvct_ok = cntvct_functional();
 
-	patch_vdso(&vdso_start);
+	patch_vdso(vdso_start);
 
 	return 0;
 }