From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Neuling Subject: [PATCH] Restrict stack space reservation to rlimit Date: Mon, 08 Feb 2010 11:28:43 +1100 Message-ID: <19732.1265588923@neuling.org> References: <3984.1265416993@neuling.org> <20100206042038.GB32246@kryten> <10125.1265451732@neuling.org> <18033.1265587672@neuling.org> Cc: Ollie Wild , Alexander Viro , Oleg Nesterov , James Morris , Ingo Molnar , linux-fsdevel@vger.kernel.org, Anton Blanchard , stable@kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, Serge Hallyn , WANG Cong , Paul Mackerras , benh@kernel.crashing.org, miltonm@bga.com, aeb@cwi.nl To: Andrew Morton , Linus Torvalds Return-path: In-reply-to: <18033.1265587672@neuling.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org When reserving stack space for a new process, make sure we're not attempting to allocate more than rlimit allows. Also, reserve the same stack size independent of page size. This fixes a bug cause by b6a2fea39318e43fee84fa7b0b90d68bed92d2ba "mm: variable length argument support" and unmasked by fc63cf237078c86214abcb2ee9926d8ad289da9b "exec: setup_arg_pages() fails to return errors". Signed-off-by: Michael Neuling Cc: Anton Blanchard Cc: stable@kernel.org --- Update commit message to include patch name and SHA1 of related patches. fs/exec.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) Index: clone1/fs/exec.c =================================================================== --- clone1.orig/fs/exec.c +++ clone1/fs/exec.c @@ -554,7 +554,7 @@ static int shift_arg_pages(struct vm_are return 0; } -#define EXTRA_STACK_VM_PAGES 20 /* random */ +#define EXTRA_STACK_VM_SIZE 81920UL /* randomly 20 4K pages */ /* * Finalizes the stack vm_area_struct. The flags and permissions are updated, @@ -627,10 +627,13 @@ int setup_arg_pages(struct linux_binprm goto out_unlock; } + stack_base = min(EXTRA_STACK_VM_SIZE, + current->signal->rlim[RLIMIT_STACK].rlim_cur) - + PAGE_SIZE; #ifdef CONFIG_STACK_GROWSUP - stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; + stack_base = vma->vm_end + stack_base; #else - stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; + stack_base = vma->vm_start - stack_base; #endif ret = expand_stack(vma, stack_base); if (ret)