From 24cb329bdf1085b4a6826cc33b0d68cd92a7a55d Mon Sep 17 00:00:00 2001 From: Huacai Chen Date: Thu, 5 Apr 2018 16:18:18 -0700 Subject: [PATCH] zboot: fix stack protector in compressed boot phase commit 7bbaf27d9c83037b6e60a818e57bdbedf6bc15be upstream. Calling __stack_chk_guard_setup() in decompress_kernel() is too late that stack checking always fails for decompress_kernel() itself. So remove __stack_chk_guard_setup() and initialize __stack_chk_guard before we call decompress_kernel(). Original code comes from ARM but also used for MIPS and SH, so fix them together. If without this fix, compressed booting of these archs will fail because stack checking is enabled by default (>=4.16). Link: http://lkml.kernel.org/r/1522226933-29317-1-git-send-email-chenhc@lemote.com Fixes: 8779657d29c0 ("stackprotector: Introduce CONFIG_CC_STACKPROTECTOR_STRONG") Signed-off-by: Huacai Chen Acked-by: James Hogan Acked-by: Kees Cook Acked-by: Rich Felker Cc: Ralf Baechle Cc: Russell King Cc: Yoshinori Sato Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.16: Only ARM has this problem] Signed-off-by: Ben Hutchings --- arch/arm/boot/compressed/misc.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c index d4f891f56996..d39edb1f7f41 100644 --- a/arch/arm/boot/compressed/misc.c +++ b/arch/arm/boot/compressed/misc.c @@ -127,12 +127,7 @@ asmlinkage void __div0(void) error("Attempting division by 0!"); } -unsigned long __stack_chk_guard; - -void __stack_chk_guard_setup(void) -{ - __stack_chk_guard = 0x000a0dff; -} +const unsigned long __stack_chk_guard = 0x000a0dff; void __stack_chk_fail(void) { @@ -149,8 +144,6 @@ decompress_kernel(unsigned long output_start, unsigned long free_mem_ptr_p, { int ret; - __stack_chk_guard_setup(); - output_data = (unsigned char *)output_start; free_mem_ptr = free_mem_ptr_p; free_mem_end_ptr = free_mem_ptr_end_p;