4.14-stable review patch. If anyone has any objections, please let me know.
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From: Jinbum Park jinb.park7@gmail.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@chromium.org Signed-off-by: Jinbum Park jinb.park7@gmail.com Signed-off-by: Russell King rmk+kernel@armlinux.org.uk Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.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; }