From: Aleksa Sarai <asarai@suse.de>
To: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Christian Brauner <christian@brauner.io>,
Kees Cook <keescook@chromium.org>
Cc: Aleksa Sarai <cyphar@cyphar.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Al Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
libc-alpha@sourceware.org, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH RESEND v3 3/4] sched_setattr: switch to copy_struct_from_user()
Date: Tue, 1 Oct 2019 05:15:25 +1000 [thread overview]
Message-ID: <20190930191526.19544-4-asarai@suse.de> (raw)
In-Reply-To: <20190930191526.19544-1-asarai@suse.de>
From: Aleksa Sarai <cyphar@cyphar.com>
The change is very straightforward, and helps unify the syscall
interface for struct-from-userspace syscalls. Ideally we could also
unify sched_getattr(2)-style syscalls as well, but unfortunately the
correct semantics for such syscalls are much less clear (see [1] for
more detail). In future we could come up with a more sane idea for how
the syscall interface should look.
[1]: commit 1251201c0d34 ("sched/core: Fix uclamp ABI bug, clean up and
robustify sched_read_attr() ABI logic and code")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
kernel/sched/core.c | 43 +++++++------------------------------------
1 file changed, 7 insertions(+), 36 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7880f4f64d0e..dd05a378631a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5106,9 +5106,6 @@ static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *a
u32 size;
int ret;
- if (!access_ok(uattr, SCHED_ATTR_SIZE_VER0))
- return -EFAULT;
-
/* Zero the full structure, so that a short copy will be nice: */
memset(attr, 0, sizeof(*attr));
@@ -5116,45 +5113,19 @@ static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *a
if (ret)
return ret;
- /* Bail out on silly large: */
- if (size > PAGE_SIZE)
- goto err_size;
-
/* ABI compatibility quirk: */
if (!size)
size = SCHED_ATTR_SIZE_VER0;
-
- if (size < SCHED_ATTR_SIZE_VER0)
+ if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
goto err_size;
- /*
- * If we're handed a bigger struct than we know of,
- * ensure all the unknown bits are 0 - i.e. new
- * user-space does not rely on any kernel feature
- * extensions we dont know about yet.
- */
- if (size > sizeof(*attr)) {
- unsigned char __user *addr;
- unsigned char __user *end;
- unsigned char val;
-
- addr = (void __user *)uattr + sizeof(*attr);
- end = (void __user *)uattr + size;
-
- for (; addr < end; addr++) {
- ret = get_user(val, addr);
- if (ret)
- return ret;
- if (val)
- goto err_size;
- }
- size = sizeof(*attr);
+ ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
+ if (ret) {
+ if (ret == -E2BIG)
+ goto err_size;
+ return ret;
}
- ret = copy_from_user(attr, uattr, size);
- if (ret)
- return -EFAULT;
-
if ((attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) &&
size < SCHED_ATTR_SIZE_VER1)
return -EINVAL;
@@ -5354,7 +5325,7 @@ sched_attr_copy_to_user(struct sched_attr __user *uattr,
* sys_sched_getattr - similar to sched_getparam, but with sched_attr
* @pid: the pid in question.
* @uattr: structure containing the extended parameters.
- * @usize: sizeof(attr) that user-space knows about, for forwards and backwards compatibility.
+ * @usize: sizeof(attr) for fwd/bwd comp.
* @flags: for future extension.
*/
SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
--
2.23.0
next prev parent reply other threads:[~2019-09-30 21:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-30 19:15 [PATCH RESEND v3 0/4] lib: introduce copy_struct_from_user() helper Aleksa Sarai
2019-09-30 19:15 ` [PATCH RESEND v3 1/4] " Aleksa Sarai
2019-09-30 23:37 ` Kees Cook
2019-10-01 0:26 ` Aleksa Sarai
2019-09-30 19:15 ` [PATCH RESEND v3 2/4] clone3: switch to copy_struct_from_user() Aleksa Sarai
2019-09-30 23:42 ` Kees Cook
2019-10-01 0:40 ` Aleksa Sarai
2019-09-30 19:15 ` Aleksa Sarai [this message]
2019-09-30 23:43 ` [PATCH RESEND v3 3/4] sched_setattr: " Kees Cook
2019-09-30 19:15 ` [PATCH RESEND v3 4/4] perf_event_open: " Aleksa Sarai
2019-09-30 23:44 ` Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190930191526.19544-4-asarai@suse.de \
--to=asarai@suse.de \
--cc=alexander.shishkin@linux.intel.com \
--cc=christian@brauner.io \
--cc=cyphar@cyphar.com \
--cc=jolsa@redhat.com \
--cc=keescook@chromium.org \
--cc=libc-alpha@sourceware.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
--cc=torvalds@linux-foundation.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).