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authorKees Cook <keescook@chromium.org>2015-04-14 15:48:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-14 16:49:05 -0700
commitc6f5b001e65cdac592b65a08c5d2dd179cfba568 (patch)
tree3039e744e13eac169969882aed3226a8f6ce6186 /arch/s390/include/asm/elf.h
parent2b68f6caeac271620cd2f9362aeaed360e317df0 (diff)
downloadlinux-linaro-stable-c6f5b001e65cdac592b65a08c5d2dd179cfba568.tar.gz
s390: redefine randomize_et_dyn for ELF_ET_DYN_BASE
In preparation for moving ET_DYN randomization into the ELF loader (which requires a static ELF_ET_DYN_BASE), this redefines s390's existing ET_DYN randomization in a call to arch_mmap_rnd(). This refactoring results in the same ET_DYN randomization on s390. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/s390/include/asm/elf.h')
-rw-r--r--arch/s390/include/asm/elf.h8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h
index c9c875d9ed31..f8db4781a4c2 100644
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -161,10 +161,12 @@ extern unsigned int vdso_enabled;
/* This is the location that an ET_DYN program is loaded if exec'ed. Typical
use of this is to invoke "./ld.so someprog" to test out a new version of
the loader. We need to make sure that it is out of the way of the program
- that it will "exec", and that there is sufficient room for the brk. */
-
+ that it will "exec", and that there is sufficient room for the brk. 64-bit
+ tasks are aligned to 4GB. */
extern unsigned long randomize_et_dyn(void);
-#define ELF_ET_DYN_BASE randomize_et_dyn()
+#define ELF_ET_DYN_BASE (randomize_et_dyn() + (is_32bit_task() ? \
+ (STACK_TOP / 3 * 2) : \
+ (STACK_TOP / 3 * 2) & ~((1UL << 32) - 1)))
/* This yields a mask that user programs can use to figure out what
instruction set this CPU supports. */