zboot: fix stack protector in compressed boot phase

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 <chenhc@lemote.com>
Acked-by: James Hogan <jhogan@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Rich Felker <dalias@libc.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c
index 16a8a804e95804fd7ce3140bf7e174e35d169fdd..e8fe51f4e97a8e2a2040e0a37195babef16bdefc 100644 (file)
--- a/arch/arm/boot/compressed/misc.c
+++ b/arch/arm/boot/compressed/misc.c
@@ -128,12 +128,7 @@ 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)
 {
@@ -150,8 +145,6 @@ 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;

diff --git a/arch/mips/boot/compressed/decompress.c b/arch/mips/boot/compressed/decompress.c
index fdf99e9dd4c3966e0b16c5d59cb9ae46d5af1b7f..81df9047e1109af762a03dc65c80278f67dceef8 100644 (file)
--- a/arch/mips/boot/compressed/decompress.c
+++ b/arch/mips/boot/compressed/decompress.c
@@ -76,12 +76,7 @@ void error(char *x)
 #include "../../../../lib/decompress_unxz.c"
 #endif
 
-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)
 {
@@ -92,8 +87,6 @@ void decompress_kernel(unsigned long boot_heap_start)
 {
        unsigned long zimage_start, zimage_size;
 
-       __stack_chk_guard_setup();
-
        zimage_start = (unsigned long)(&__image_begin);
        zimage_size = (unsigned long)(&__image_end) -
            (unsigned long)(&__image_begin);

diff --git a/arch/sh/boot/compressed/misc.c b/arch/sh/boot/compressed/misc.c
index 627ce8e75e016422102f0572c564bef3df2958b2..c15cac9251b91fadb307e50dbb114fb2e46aa1ed 100644 (file)
--- a/arch/sh/boot/compressed/misc.c
+++ b/arch/sh/boot/compressed/misc.c
@@ -104,12 +104,7 @@ static void error(char *x)
        while(1);       /* Halt */
 }
 
-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)
 {
@@ -130,8 +125,6 @@ void decompress_kernel(void)
 {
        unsigned long output_addr;
 
-       __stack_chk_guard_setup();
-
 #ifdef CONFIG_SUPERH64
        output_addr = (CONFIG_MEMORY_START + 0x2000);
 #else