| Message ID | 20180228142951.GA3136@pjb1027-Latitude-E5410 (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Feb 28, 2018 at 6:29 AM, Jinbum Park <jinb.park7@gmail.com> wrote: > 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. > > Signed-off-by: Jinbum Park <jinb.park7@gmail.com> Thanks! Acked-by: Kees Cook <keescook@chromium.org> -Kees > --- > arch/arm/include/asm/vdso.h | 2 -- > arch/arm/kernel/vdso.c | 12 +++++++----- > 2 files changed, 7 insertions(+), 7 deletions(-) > > diff --git a/arch/arm/include/asm/vdso.h b/arch/arm/include/asm/vdso.h > index 9c99e81..5b85889 100644 > --- a/arch/arm/include/asm/vdso.h > +++ b/arch/arm/include/asm/vdso.h > @@ -12,8 +12,6 @@ > > 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 */ > diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c > index a4d6dc0..f4dd7f9 100644 > --- 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; > } > -- > 1.9.1 >
diff --git a/arch/arm/include/asm/vdso.h b/arch/arm/include/asm/vdso.h index 9c99e81..5b85889 100644 --- a/arch/arm/include/asm/vdso.h +++ b/arch/arm/include/asm/vdso.h @@ -12,8 +12,6 @@ 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 */ diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c index a4d6dc0..f4dd7f9 100644 --- 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; }
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. Signed-off-by: Jinbum Park <jinb.park7@gmail.com> --- arch/arm/include/asm/vdso.h | 2 -- arch/arm/kernel/vdso.c | 12 +++++++----- 2 files changed, 7 insertions(+), 7 deletions(-)