diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2020-07-12 08:23:54 -0500 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2020-07-21 08:24:52 -0500 |
| commit | d8b9cd549ecf0f3dc8da42ada5f0ce73e8ed5f1e (patch) | |
| tree | 82f46fe91d016c1dec6665d7b1031805a24566b5 /fs | |
| parent | 0c9cdff054aec0836bb38a449e860793849c3f84 (diff) | |
exec: Factor bprm_stack_limits out of prepare_arg_pages
In preparation for implementiong kernel_execve (which will take kernel
pointers not userspace pointers) factor out bprm_stack_limits out of
prepare_arg_pages. This separates the counting which depends upon the
getting data from userspace from the calculations of the stack limits
which is usable in kernel_execve.
The remove prepare_args_pages and compute bprm->argc and bprm->envc
directly in do_execveat_common, before bprm_stack_limits is called.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/87365u6x60.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/exec.c | 23 |
1 files changed, 12 insertions, 11 deletions
diff --git a/fs/exec.c b/fs/exec.c index 50508892fa71..f8135dc149b3 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -448,19 +448,10 @@ static int count(struct user_arg_ptr argv, int max) return i; } -static int prepare_arg_pages(struct linux_binprm *bprm, - struct user_arg_ptr argv, struct user_arg_ptr envp) +static int bprm_stack_limits(struct linux_binprm *bprm) { unsigned long limit, ptr_size; - bprm->argc = count(argv, MAX_ARG_STRINGS); - if (bprm->argc < 0) - return bprm->argc; - - bprm->envc = count(envp, MAX_ARG_STRINGS); - if (bprm->envc < 0) - return bprm->envc; - /* * Limit to 1/4 of the max stack size or 3/4 of _STK_LIM * (whichever is smaller) for the argv+env strings. @@ -1964,7 +1955,17 @@ static int do_execveat_common(int fd, struct filename *filename, goto out_ret; } - retval = prepare_arg_pages(bprm, argv, envp); + retval = count(argv, MAX_ARG_STRINGS); + if (retval < 0) + goto out_free; + bprm->argc = retval; + + retval = count(envp, MAX_ARG_STRINGS); + if (retval < 0) + goto out_free; + bprm->envc = retval; + + retval = bprm_stack_limits(bprm); if (retval < 0) goto out_free; |