From: Aleksa Sarai <cyphar@cyphar.com>
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>
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 v1 4/4] perf_event_open: switch to copy_struct_from_user()
Date: Wed, 25 Sep 2019 18:59:15 +0200 [thread overview]
Message-ID: <20190925165915.8135-5-cyphar@cyphar.com> (raw)
In-Reply-To: <20190925165915.8135-1-cyphar@cyphar.com>
The change is very straightforward, and helps unify the syscall
interface for struct-from-userspace syscalls.
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
kernel/events/core.c | 47 +++++++++-----------------------------------
1 file changed, 9 insertions(+), 38 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0463c1151bae..038ed126bc1b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10498,55 +10498,26 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
u32 size;
int ret;
- if (!access_ok(uattr, PERF_ATTR_SIZE_VER0))
- return -EFAULT;
-
- /*
- * zero the full structure, so that a short copy will be nice.
- */
+ /* Zero the full structure, so that a short copy will be nice. */
memset(attr, 0, sizeof(*attr));
ret = get_user(size, &uattr->size);
if (ret)
return ret;
- if (size > PAGE_SIZE) /* silly large */
- goto err_size;
-
- if (!size) /* abi compat */
+ /* ABI compatibility quirk: */
+ if (!size)
size = PERF_ATTR_SIZE_VER0;
-
- if (size < PERF_ATTR_SIZE_VER0)
+ if (size < PERF_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;
-
attr->size = size;
if (attr->__reserved_1)
--
2.23.0
next prev parent reply other threads:[~2019-09-25 17:00 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 16:59 [PATCH v1 0/4] lib: introduce copy_struct_from_user() helper Aleksa Sarai
2019-09-25 16:59 ` [PATCH v1 1/4] " Aleksa Sarai
2019-09-25 17:10 ` Linus Torvalds
2019-09-25 17:20 ` Aleksa Sarai
2019-09-25 17:48 ` Linus Torvalds
2019-09-25 18:04 ` Al Viro
2019-09-25 18:13 ` Linus Torvalds
2019-09-25 19:43 ` Al Viro
2019-09-25 20:23 ` Linus Torvalds
2019-09-25 17:18 ` Christian Brauner
2019-09-25 17:20 ` Christian Brauner
2019-09-25 19:16 ` kbuild test robot
2019-09-25 20:47 ` kbuild test robot
2019-09-25 16:59 ` [PATCH v1 2/4] clone3: switch to copy_struct_from_user() Aleksa Sarai
2019-09-25 17:22 ` Christian Brauner
2019-09-25 18:59 ` kbuild test robot
2019-09-25 19:08 ` kbuild test robot
2019-09-25 16:59 ` [PATCH v1 3/4] sched_setattr: " Aleksa Sarai
2019-09-25 16:59 ` Aleksa Sarai [this message]
2019-09-25 17:09 ` [PATCH v1 0/4] lib: introduce copy_struct_from_user() helper Christian Brauner
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=20190925165915.8135-5-cyphar@cyphar.com \
--to=cyphar@cyphar.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=christian@brauner.io \
--cc=jolsa@redhat.com \
--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).