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authorJiri Kosina <jkosina@suse.cz>2011-04-14 15:22:09 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-21 14:32:49 -0700
commit510edc2527fd3d25b6119d980dddff7213868b19 (patch)
treeaa2760509c081bcf7a52914f4ef3638f08af7b86 /fs
parent411999731208babec42c9d17f931a8d87586b05f (diff)
downloadlinux-linaro-android-510edc2527fd3d25b6119d980dddff7213868b19.tar.gz
brk: COMPAT_BRK: fix detection of randomized brk
commit 4471a675dfc7ca676c165079e91c712b09dc9ce4 upstream. 5520e89 ("brk: fix min_brk lower bound computation for COMPAT_BRK") tried to get the whole logic of brk randomization for legacy (libc5-based) applications finally right. It turns out that the way to detect whether brk has actually been randomized in the end or not introduced by that patch still doesn't work for those binaries, as reported by Geert: : /sbin/init from my old m68k ramdisk exists prematurely. : : Before the patch: : : | brk(0x80005c8e) = 0x80006000 : : After the patch: : : | brk(0x80005c8e) = 0x80005c8e : : Old libc5 considers brk() to have failed if the return value is not : identical to the requested value. I don't like it, but currently see no better option than a bit flag in task_struct to catch the CONFIG_COMPAT_BRK && randomize_va_space == 2 case. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs')
-rw-r--r--fs/binfmt_elf.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index d5b640ba6cb..70470b2b7f7 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -941,9 +941,13 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
current->mm->start_stack = bprm->p;
#ifdef arch_randomize_brk
- if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1))
+ if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
current->mm->brk = current->mm->start_brk =
arch_randomize_brk(current->mm);
+#ifdef CONFIG_COMPAT_BRK
+ current->brk_randomized = 1;
+#endif
+ }
#endif
if (current->personality & MMAP_PAGE_ZERO) {