From: Aleksa Sarai <cyphar@cyphar.com> To: Al Viro <viro@zeniv.linux.org.uk>, Jeff Layton <jlayton@kernel.org>, "J. Bruce Fields" <bfields@fieldses.org>, Arnd Bergmann <arnd@arndb.de>, David Howells <dhowells@redhat.com>, Shuah Khan <shuah@kernel.org>, Shuah Khan <skhan@linuxfoundation.org>, Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>, Christian Brauner <christian@brauner.io> Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Alexander Shishkin <alexander.shishkin@linux.intel.com>, Rasmus Villemoes <linux@rasmusvillemoes.dk>, Alexei Starovoitov <ast@kernel.org>, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, sparclinux@vger.kernel.org, Jiri Olsa <jolsa@redhat.com>, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Tycho Andersen <tycho@tycho.ws>, Aleksa Sarai <asarai@suse.de>, linux-mips@vger.kernel.org, linux-xtensa@linux-xtensa.org, Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>, linuxppc-dev@lists.ozlabs.org, Aleksa Sarai <cyphar@cyphar.com>, Andy Lutomirski <luto@kernel.org>, Namhyung Kim <namhyung@kernel.org>, David Drysdale <drysdale@google.com>, linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-api@vger.kernel.org, Chanho Min <chanho.min@lge.com>, Oleg Nesterov <oleg@redhat.com>, Eric Biederman <ebiederm@xmission.com>, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, containers@lists.linux-foundation.org Subject: [PATCH v12 04/12] perf_event_open: switch to copy_struct_from_user() Date: Thu, 5 Sep 2019 06:19:25 +1000 Message-ID: <20190904201933.10736-5-cyphar@cyphar.com> (raw) In-Reply-To: <20190904201933.10736-1-cyphar@cyphar.com> The change is very straightforward, and takes advantage of the (very minor) efficiency improvements in copy_struct_from_user() -- that the memchr_inv() check is done on a buffer instead of one-at-at-time with get_user(). Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> --- kernel/events/core.c | 45 ++++++++------------------------------------ 1 file changed, 8 insertions(+), 37 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 0463c1151bae..fe5f58443ba6 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) 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 index Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-09-04 20:19 [PATCH v12 00/12] namei: openat2(2) path resolution restrictions Aleksa Sarai 2019-09-04 20:19 ` [PATCH v12 01/12] lib: introduce copy_struct_{to,from}_user helpers Aleksa Sarai 2019-09-04 20:48 ` [PATCH v12 01/12] lib: introduce copy_struct_{to, from}_user helpers Linus Torvalds 2019-09-04 21:00 ` [PATCH v12 01/12] lib: introduce copy_struct_{to,from}_user helpers Randy Dunlap 2019-09-05 7:32 ` Peter Zijlstra 2019-09-05 9:26 ` Aleksa Sarai 2019-09-05 9:43 ` Peter Zijlstra 2019-09-05 10:57 ` Peter Zijlstra 2019-09-11 10:37 ` Aleksa Sarai 2019-09-05 13:35 ` Aleksa Sarai 2019-09-05 17:01 ` Aleksa Sarai 2019-09-05 8:43 ` Rasmus Villemoes 2019-09-05 9:50 ` Aleksa Sarai 2019-09-05 10:45 ` Christian Brauner 2019-09-05 9:09 ` [PATCH v12 01/12] lib: introduce copy_struct_{to, from}_user helpers Andreas Schwab 2019-09-05 10:13 ` Gabriel Paubert 2019-09-05 11:05 ` [PATCH v12 01/12] lib: introduce copy_struct_{to,from}_user helpers Christian Brauner 2019-09-05 11:17 ` Rasmus Villemoes 2019-09-05 11:29 ` Christian Brauner 2019-09-05 13:40 ` Aleksa Sarai 2019-09-05 11:09 ` Christian Brauner 2019-09-05 11:27 ` Aleksa Sarai 2019-09-05 11:40 ` Christian Brauner 2019-09-05 18:07 ` Al Viro 2019-09-05 18:23 ` Christian Brauner 2019-09-05 18:28 ` Al Viro 2019-09-05 18:35 ` Christian Brauner 2019-09-05 19:56 ` Aleksa Sarai 2019-09-05 22:31 ` Al Viro 2019-09-06 7:00 ` Christian Brauner 2019-09-05 23:00 ` Aleksa Sarai 2019-09-05 23:49 ` Al Viro 2019-09-06 0:09 ` Aleksa Sarai 2019-09-06 0:14 ` Al Viro 2019-09-04 20:19 ` [PATCH v12 02/12] clone3: switch to copy_struct_from_user() Aleksa Sarai 2019-09-04 20:19 ` [PATCH v12 03/12] sched_setattr: switch to copy_struct_{to, from}_user() Aleksa Sarai 2019-09-04 20:19 ` Aleksa Sarai [this message] 2019-09-04 20:19 ` [PATCH v12 05/12] namei: obey trailing magic-link DAC permissions Aleksa Sarai 2019-09-17 21:30 ` Jann Horn 2019-09-18 13:51 ` Aleksa Sarai 2019-09-18 15:46 ` Aleksa Sarai 2019-09-04 20:19 ` [PATCH v12 06/12] procfs: switch magic-link modes to be more sane Aleksa Sarai 2019-09-04 20:19 ` [PATCH v12 07/12] open: O_EMPTYPATH: procfs-less file descriptor re-opening Aleksa Sarai 2019-09-04 20:19 ` [PATCH v12 08/12] namei: O_BENEATH-style path resolution flags Aleksa Sarai 2019-09-04 20:19 ` [PATCH v12 09/12] namei: LOOKUP_IN_ROOT: chroot-like path resolution Aleksa Sarai 2019-09-04 20:19 ` [PATCH v12 10/12] namei: aggressively check for nd->root escape on ".." resolution Aleksa Sarai 2019-09-04 21:09 ` Linus Torvalds 2019-09-04 21:35 ` Linus Torvalds 2019-09-04 21:36 ` Linus Torvalds 2019-09-04 21:48 ` Aleksa Sarai 2019-09-04 22:16 ` Linus Torvalds 2019-09-04 22:31 ` David Howells 2019-09-04 22:38 ` Linus Torvalds 2019-09-04 23:29 ` Al Viro 2019-09-04 23:44 ` Linus Torvalds 2019-09-04 20:19 ` [PATCH v12 11/12] open: openat2(2) syscall Aleksa Sarai 2019-09-04 21:00 ` Randy Dunlap 2019-09-07 12:40 ` Jeff Layton 2019-09-07 16:58 ` Linus Torvalds 2019-09-07 17:42 ` Andy Lutomirski 2019-09-07 17:45 ` Linus Torvalds 2019-09-07 18:15 ` Andy Lutomirski 2019-09-10 6:35 ` Ingo Molnar 2019-09-08 16:24 ` Aleksa Sarai 2019-09-04 20:19 ` [PATCH v12 12/12] selftests: add openat2(2) selftests Aleksa Sarai
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