From: Radu Caragea Date: Tue, 13 Aug 2013 23:00:59 +0000 (-0700) Subject: x86 get_unmapped_area(): use proper mmap base for bottom-up direction X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=df54d6fa54275ce59660453e29d1228c2b45a826;p=openwrt%2Fstaging%2Fblogic.git 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 Cc: Oleg Nesterov Reviewed-by: Rik van Riel Acked-by: Ingo Molnar Cc: Adrian Sendroiu Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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,