From patchwork Tue Oct 1 01:10:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aleksa Sarai X-Patchwork-Id: 34755 Received: (qmail 45871 invoked by alias); 1 Oct 2019 01:12:14 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 45860 invoked by uid 89); 1 Oct 2019 01:12:13 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-24.6 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_MANYTO, RCVD_IN_DNSWL_LOW, SPF_HELO_PASS, SPF_PASS autolearn=ham version=3.3.1 spammy= X-HELO: mx2.mailbox.org From: Aleksa Sarai To: Ingo Molnar , Peter Zijlstra , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Christian Brauner , Kees Cook Cc: Aleksa Sarai , Rasmus Villemoes , Al Viro , Linus Torvalds , libc-alpha@sourceware.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 2/4] clone3: switch to copy_struct_from_user() Date: Tue, 1 Oct 2019 11:10:53 +1000 Message-Id: <20191001011055.19283-3-cyphar@cyphar.com> In-Reply-To: <20191001011055.19283-1-cyphar@cyphar.com> References: <20191001011055.19283-1-cyphar@cyphar.com> MIME-Version: 1.0 The change is very straightforward, and helps unify the syscall interface for struct-from-userspace syscalls. Additionally, explicitly define CLONE_ARGS_SIZE_VER0 to match the other users of the struct-extension pattern. Reviewed-by: Kees Cook Signed-off-by: Aleksa Sarai Reviewed-by: Christian Brauner --- include/uapi/linux/sched.h | 2 ++ kernel/fork.c | 34 +++++++--------------------------- 2 files changed, 9 insertions(+), 27 deletions(-) diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index b3105ac1381a..0945805982b4 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -47,6 +47,8 @@ struct clone_args { __aligned_u64 tls; }; +#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */ + /* * Scheduling policies */ diff --git a/kernel/fork.c b/kernel/fork.c index f9572f416126..2ef529869c64 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2525,39 +2525,19 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, #ifdef __ARCH_WANT_SYS_CLONE3 noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, struct clone_args __user *uargs, - size_t size) + size_t usize) { + int err; struct clone_args args; - if (unlikely(size > PAGE_SIZE)) + if (unlikely(usize > PAGE_SIZE)) return -E2BIG; - - if (unlikely(size < sizeof(struct clone_args))) + if (unlikely(usize < CLONE_ARGS_SIZE_VER0)) return -EINVAL; - if (unlikely(!access_ok(uargs, size))) - return -EFAULT; - - if (size > sizeof(struct clone_args)) { - unsigned char __user *addr; - unsigned char __user *end; - unsigned char val; - - addr = (void __user *)uargs + sizeof(struct clone_args); - end = (void __user *)uargs + size; - - for (; addr < end; addr++) { - if (get_user(val, addr)) - return -EFAULT; - if (val) - return -E2BIG; - } - - size = sizeof(struct clone_args); - } - - if (copy_from_user(&args, uargs, size)) - return -EFAULT; + err = copy_struct_from_user(&args, sizeof(args), uargs, usize); + if (err) + return err; /* * Verify that higher 32bits of exit_signal are unset and that