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authorHeiko Carstens <heiko.carstens@de.ibm.com>2011-01-12 09:55:31 +0100
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2011-01-12 09:55:25 +0100
commitd2c9dfccbc3a449b9677772e7496e2656049d9f3 (patch)
treef62cf27ddee310af28244bcfbc8eb2e197ed629c /arch/s390
parent3351918282fd664e918a3175ddfae9b15656122e (diff)
downloadlinux-linaro-android-d2c9dfccbc3a449b9677772e7496e2656049d9f3.tar.gz
[S390] Randomize PIEs
Randomize ELF_ET_DYN_BASE, which is used when loading position independent executables. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/elf.h4
-rw-r--r--arch/s390/kernel/process.c11
2 files changed, 14 insertions, 1 deletions
diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h
index 457fb7c1623..10c029cfcc7 100644
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -161,7 +161,9 @@ extern unsigned int vdso_enabled;
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. */
-#define ELF_ET_DYN_BASE (STACK_TOP / 3 * 2)
+
+extern unsigned long randomize_et_dyn(unsigned long base);
+#define ELF_ET_DYN_BASE (randomize_et_dyn(STACK_TOP / 3 * 2))
/* This yields a mask that user programs can use to figure out what
instruction set this CPU supports. */
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 26d48fe7299..a895e69379f 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -359,3 +359,14 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
return mm->brk;
return ret;
}
+
+unsigned long randomize_et_dyn(unsigned long base)
+{
+ unsigned long ret = PAGE_ALIGN(base + brk_rnd());
+
+ if (!(current->flags & PF_RANDOMIZE))
+ return base;
+ if (ret < base)
+ return base;
+ return ret;
+}