On Tue, Mar 22, 2016 at 12:32 AM, Baoquan He <b...@redhat.com> wrote: > From: Yinghai Lu <ying...@kernel.org> > > Relocation handling performs bounds checking on the relocated > addresses. The existing code uses output_len (VO size plus relocs > size) as the max address. This is not right since the max_addr check > should stop at the end of VO and exclude bss, brk, etc, which follows. > The valid range should be VO [_text, __bss_start] in the loaded > physical address space. > > In this patch, add export for __bss_start to voffset.h and use it to > get the correct max_addr. > > Signed-off-by: Yinghai Lu <ying...@kernel.org> > Cc: Baoquan He <b...@redhat.com>
Acked-by: Kees Cook <keesc...@chromium.org> -Kees > --- > v2->v3: > Adjust patch log. > v3->v4: > Kees help rewrite the patch log > > arch/x86/boot/compressed/Makefile | 2 +- > arch/x86/boot/compressed/misc.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/boot/compressed/Makefile > b/arch/x86/boot/compressed/Makefile > index fef80fa..2e7c0ce 100644 > --- a/arch/x86/boot/compressed/Makefile > +++ b/arch/x86/boot/compressed/Makefile > @@ -41,7 +41,7 @@ LDFLAGS_vmlinux := -T > hostprogs-y := mkpiggy > HOST_EXTRACFLAGS += -I$(srctree)/tools/include > > -sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] > \(_text\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p' > +sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] > \(_text\|__bss_start\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p' > > quiet_cmd_voffset = VOFFSET $@ > cmd_voffset = $(NM) $< | sed -n $(sed-voffset) > $@ > diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c > index def6207..029f42f 100644 > --- a/arch/x86/boot/compressed/misc.c > +++ b/arch/x86/boot/compressed/misc.c > @@ -259,7 +259,7 @@ static void handle_relocations(void *output, unsigned > long output_len) > int *reloc; > unsigned long delta, map, ptr; > unsigned long min_addr = (unsigned long)output; > - unsigned long max_addr = min_addr + output_len; > + unsigned long max_addr = min_addr + (VO___bss_start - VO__text); > > /* > * Calculate the delta between where vmlinux was linked to load > -- > 2.5.0 > -- Kees Cook Chrome OS & Brillo Security
