Randomizes -pie compiled binaries from PAGE_SIZE up to
ELF_ET_DYN_BASE.
0 -> PAGE_SIZE is excluded to allow NULL ptr accesses
to fail.
Signed-off-by: Marcus Meissner <meissner@xxxxxxx>
----
binfmt_elf.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- linux-2.6.18/fs/binfmt_elf.c.xx 2006-10-20 10:42:03.000000000 +0200
+++ linux-2.6.18/fs/binfmt_elf.c 2006-10-20 10:51:27.000000000 +0200
@@ -856,7 +856,13 @@
* default mmap base, as well as whatever program they
* might try to exec. This is because the brk will
* follow the loader, and is not movable. */
- load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
+ if (current->flags & PF_RANDOMIZE)
+ load_bias = randomize_range(PAGE_SIZE,
+ ELF_ET_DYN_BASE,
+ 0);
+ ELF_ET_DYN_BASE, 0);