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| author | Radu Caragea <sinaelgl@gmail.com> | 2013-08-13 16:00:59 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-08-13 17:57:49 -0700 |
| commit | df54d6fa54275ce59660453e29d1228c2b45a826 (patch) | |
| tree | 8e8c54da4a1cd7f9caca46b2b39d673c3bf7f793 | |
| parent | c7dd3392ad469e6ba125170ad29f881bed85b678 (diff) | |
| download | lwn-df54d6fa54275ce59660453e29d1228c2b45a826.tar.gz lwn-df54d6fa54275ce59660453e29d1228c2b45a826.zip | |
x86 get_unmapped_area(): use proper mmap base for bottom-up direction
When the stack is set to unlimited, the bottomup direction is used for
mmap-ings but the mmap_base is not used and thus effectively renders
ASLR for mmapings along with PIE useless.
Cc: Michel Lespinasse <walken@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Sendroiu <molecula2788@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/x86/kernel/sys_x86_64.c | 2 | ||||
| -rw-r--r-- | arch/x86/mm/mmap.c | 2 | ||||
| -rw-r--r-- | include/linux/sched.h | 1 |
3 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index dbded5aedb81..48f8375e4c6b 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -101,7 +101,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin, *begin = new_begin; } } else { - *begin = TASK_UNMAPPED_BASE; + *begin = mmap_legacy_base(); *end = TASK_SIZE; } } diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index 62c29a5bfe26..f63778cb2363 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -98,7 +98,7 @@ static unsigned long mmap_base(void) * Bottom-up (legacy) layout on X86_32 did not support randomization, X86_64 * does, but not when emulating X86_32 */ -static unsigned long mmap_legacy_base(void) +unsigned long mmap_legacy_base(void) { if (mmap_is_ia32()) return TASK_UNMAPPED_BASE; diff --git a/include/linux/sched.h b/include/linux/sched.h index d722490da030..923dd6ea4a0e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -314,6 +314,7 @@ struct nsproxy; struct user_namespace; #ifdef CONFIG_MMU +extern unsigned long mmap_legacy_base(void); extern void arch_pick_mmap_layout(struct mm_struct *mm); extern unsigned long arch_get_unmapped_area(struct file *, unsigned long, unsigned long, |