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authorIngo Molnar <mingo@elte.hu>2008-02-06 22:39:44 +0100
committerIngo Molnar <mingo@elte.hu>2008-02-06 22:39:44 +0100
commit32a932332c8bad842804842eaf9651ad6268e637 (patch)
tree58f187409029f089f788c5c35ad5c200b4a555af /mm/memory.c
parent4cc6028d4040f95cdb590a87db478b42b8be0508 (diff)
downloadlwn-32a932332c8bad842804842eaf9651ad6268e637.tar.gz
lwn-32a932332c8bad842804842eaf9651ad6268e637.zip
brk randomization: introduce CONFIG_COMPAT_BRK
based on similar patch from: Pavel Machek <pavel@ucw.cz> Introduce CONFIG_COMPAT_BRK. If disabled then the kernel is free (but not obliged to) randomize the brk area. Heap randomization breaks ancient binaries, so we keep COMPAT_BRK enabled by default. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 7bb70728bb52..9d073fa0a2d0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -82,7 +82,18 @@ void * high_memory;
EXPORT_SYMBOL(num_physpages);
EXPORT_SYMBOL(high_memory);
-int randomize_va_space __read_mostly = 1;
+/*
+ * Randomize the address space (stacks, mmaps, brk, etc.).
+ *
+ * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
+ * as ancient (libc5 based) binaries can segfault. )
+ */
+int randomize_va_space __read_mostly =
+#ifdef CONFIG_COMPAT_BRK
+ 1;
+#else
+ 2;
+#endif
static int __init disable_randmaps(char *s)
{