From: ebiederm@xmission.com (Eric W. Biederman)
To: <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Al Viro <viro@zeniv.linux.org.uk>,
Luis Chamberlain <mcgrof@kernel.org>,
<linux-fsdevel@vger.kernel.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
linux-security-module@vger.kernel.org,
"Serge E. Hallyn" <serge@hallyn.com>,
James Morris <jmorris@namei.org>,
Kentaro Takeda <takedakn@nttdata.co.jp>,
Casey Schaufler <casey@schaufler-ca.com>,
John Johansen <john.johansen@canonical.com>,
Christoph Hellwig <hch@infradead.org>
Subject: [PATCH 6/7] exec: Factor bprm_stack_limits out of prepare_arg_pages
Date: Tue, 14 Jul 2020 08:31:03 -0500 [thread overview]
Message-ID: <87365u6x60.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <871rle8bw2.fsf@x220.int.ebiederm.org> (Eric W. Biederman's message of "Tue, 14 Jul 2020 08:27:41 -0500")
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.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
fs/exec.c | 23 ++++++++++++-----------
1 file 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;
--
2.25.0
next prev parent reply other threads:[~2020-07-14 13:33 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 13:27 [PATCH 0/7] Implementing kernel_execve Eric W. Biederman
2020-07-14 13:28 ` [PATCH 1/7] exec: Remove unnecessary spaces from binfmts.h Eric W. Biederman
2020-07-14 21:38 ` Kees Cook
2020-07-15 6:28 ` Christoph Hellwig
2020-07-14 13:29 ` [PATCH 2/7] exec: Factor out alloc_bprm Eric W. Biederman
2020-07-14 21:38 ` Kees Cook
2020-07-15 6:30 ` Christoph Hellwig
2020-07-14 13:29 ` [PATCH 3/7] exec: Move initialization of bprm->filename into alloc_bprm Eric W. Biederman
2020-07-14 21:38 ` Kees Cook
2020-07-15 6:34 ` Christoph Hellwig
2020-07-14 13:30 ` [PATCH 4/7] exec: Move bprm_mm_init " Eric W. Biederman
2020-07-14 21:37 ` Kees Cook
2020-07-15 6:35 ` Christoph Hellwig
2020-07-14 13:30 ` [PATCH 5/7] exec: Factor bprm_execve out of do_execve_common Eric W. Biederman
2020-07-14 21:38 ` Kees Cook
2020-07-15 6:36 ` Christoph Hellwig
2020-07-14 13:31 ` Eric W. Biederman [this message]
2020-07-14 21:41 ` [PATCH 6/7] exec: Factor bprm_stack_limits out of prepare_arg_pages Kees Cook
2020-07-15 6:38 ` Christoph Hellwig
2020-07-14 13:31 ` [PATCH 7/7] exec: Implement kernel_execve Eric W. Biederman
2020-07-14 21:49 ` Kees Cook
2020-07-15 6:42 ` Christoph Hellwig
2020-07-15 14:55 ` David Laight
2020-07-15 15:09 ` Kees Cook
2020-07-15 16:46 ` David Laight
2020-07-15 15:00 ` Kees Cook
2020-07-15 18:20 ` Christoph Hellwig
2020-07-15 6:42 ` Christoph Hellwig
2020-07-15 18:23 ` Eric W. Biederman
2020-07-14 15:32 ` [PATCH 0/7] Implementing kernel_execve Linus Torvalds
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