Messages in this thread Patch in this message | | | From | Baoquan He <> | Subject | [PATCH v4 08/20] x86, kaslr: Get correct max_addr for relocs pointer | Date | Tue, 22 Mar 2016 15:32:05 +0800 |
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From: Yinghai Lu <yinghai@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 <yinghai@kernel.org> Cc: Baoquan He <bhe@redhat.com> --- 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
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