Messages in this thread | | | Date | Mon, 26 Nov 2018 09:34:04 -0800 | From | Guenter Roeck <> | Subject | Re: [PATCH] exec: separate MM_ANONPAGES and RLIMIT_STACK accounting |
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Hi Oleg,
On Mon, Nov 26, 2018 at 01:23:07PM +0100, Oleg Nesterov wrote: > Hi Guenter, > > On 11/23, Guenter Roeck wrote: > > > > On Mon, Nov 12, 2018 at 05:09:10PM +0100, Oleg Nesterov wrote: > > > get_arg_page() checks bprm->rlim_stack.rlim_cur and re-calculates the > > > "extra" size for argv/envp pointers every time, this is a bit ugly and > > > even not strictly correct: acct_arg_size() must not account this size. > > > > > > Remove all the rlimit code in get_arg_page(). Instead, add bprm->argmin > > > calculated once at the start of __do_execve_file() and change copy_strings > > > to check bprm->p >= bprm->argmin. > > > > > > The patch adds the new helper, prepare_arg_pages() which initializes > > > bprm->argc/envc and bprm->argmin. > > > > > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > > Acked-by: Kees Cook <keescook@chromium.org> > > > > This patch results in various qemu boot failures in -next. Bisect logs > > are attached. It looks like all nommu boots are failing. > ^^^^^ > > Ah, thanks. > > Yes, I forgot about the !CONFIG_MMU version of get_arg_page() which doesn't > check RLIMIT_STACK at all. > > I'll send the trivial fix. Meanwile, could you test the patch below? to ensure > this is the only problem. >
Tested-by: Guenter Roeck <linux@roeck-us.net>
with arm:mps2-an385, xtensa:kc705-nommu, and m68k:mcf5208evb.
Thanks, Guenter
> Oleg. > > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -526,8 +526,10 @@ static int copy_strings(int argc, struct user_arg_ptr argv, > pos = bprm->p; > str += len; > bprm->p -= len; > +#ifdef CONFIG_MMU > if (bprm->p < bprm->argmin) > goto out; > +#endif > > while (len > 0) { > int offset, bytes_to_copy; >
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