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authorYinghai Lu <[email protected]>2016-04-28 17:09:08 -0700
committerIngo Molnar <[email protected]>2016-04-29 11:03:30 +0200
commit4abf061bf87bbd856c8d60199b2fba8b8f9b9fd6 (patch)
treed7e276656737cc3aa430da52a2791c1104b474d0
parent4d2d542482205d3df1a0852751f5b004cc6390cc (diff)
x86/boot: Correctly bounds-check relocations
Relocation handling performs bounds checking on the resulting calculated 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. This patch adds an export for __bss_start in voffset.h and uses it to set the correct limit for max_addr. Signed-off-by: Yinghai Lu <[email protected]> [ Rewrote the changelog. ] Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Young <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
-rw-r--r--arch/x86/boot/compressed/Makefile2
-rw-r--r--arch/x86/boot/compressed/misc.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index adef26d22224..75f2233b8414 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -57,7 +57,7 @@ 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 bee6238e7cfc..8f0253d8c7ff 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -191,7 +191,7 @@ 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