From patchwork Wed Oct 16 11:18:08 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 1177805 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ubuntu.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 46tVDn4Z9rz9sNw for ; Wed, 16 Oct 2019 22:19:21 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392708AbfJPLTV (ORCPT ); Wed, 16 Oct 2019 07:19:21 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:40230 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389063AbfJPLTU (ORCPT ); Wed, 16 Oct 2019 07:19:20 -0400 Received: from [213.220.153.21] (helo=localhost.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1iKhKo-0003tb-DZ; Wed, 16 Oct 2019 11:19:18 +0000 From: Christian Brauner To: christian.brauner@ubuntu.com Cc: ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, kafai@fb.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, yhs@fb.com, Aleksa Sarai Subject: [PATCH bpf-next v4 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Date: Wed, 16 Oct 2019 13:18:08 +0200 Message-Id: <20191016111810.1799-2-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016111810.1799-1-christian.brauner@ubuntu.com> References: <20191016034432.4418-1-christian.brauner@ubuntu.com> <20191016111810.1799-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org In v5.4-rc2 we added a new helper (cf. [1]) check_zeroed_user() which does what bpf_check_uarg_tail_zero() is doing generically. We're slowly switching such codepaths over to use check_zeroed_user() instead of using their own hand-rolled version. [1]: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper") Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Aleksa Sarai Cc: bpf@vger.kernel.org Signed-off-by: Christian Brauner --- /* v1 */ Link: https://lore.kernel.org/r/20191009160907.10981-2-christian.brauner@ubuntu.com /* v2 */ Link: https://lore.kernel.org/r/20191016004138.24845-2-christian.brauner@ubuntu.com - Alexei Starovoitov : - Add a comment in bpf_check_uarg_tail_zero() to clarify that copy_struct_from_user() should be used whenever possible instead. /* v3 */ Link: https://lore.kernel.org/r/20191016034432.4418-2-christian.brauner@ubuntu.com - Christian Brauner : - use correct checks for check_zeroed_user() /* v4 */ - Alexei Starovoitov : - remove unnecessary min() and max() calls --- kernel/bpf/syscall.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 82eabd4e38ad..8d112bc069c0 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -58,35 +58,26 @@ static const struct bpf_map_ops * const bpf_map_types[] = { * There is a ToCToU between this function call and the following * copy_from_user() call. However, this is not a concern since this function is * meant to be a future-proofing of bits. + * + * Note, instead of using bpf_check_uarg_tail_zero() followed by + * copy_from_user() use the dedicated copy_struct_from_user() helper which + * performs both tasks whenever possible. */ int bpf_check_uarg_tail_zero(void __user *uaddr, size_t expected_size, size_t actual_size) { - unsigned char __user *addr; - unsigned char __user *end; - unsigned char val; int err; if (unlikely(actual_size > PAGE_SIZE)) /* silly large */ return -E2BIG; - if (unlikely(!access_ok(uaddr, actual_size))) - return -EFAULT; - if (actual_size <= expected_size) return 0; - addr = uaddr + expected_size; - end = uaddr + actual_size; - - for (; addr < end; addr++) { - err = get_user(val, addr); - if (err) - return err; - if (val) - return -E2BIG; - } + err = check_zeroed_user(uaddr + expected_size, actual_size - expected_size); + if (err <= 0) + return err ?: -E2BIG; return 0; } From patchwork Wed Oct 16 11:18:09 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 1177806 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ubuntu.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 46tVDx1d8sz9sPT for ; Wed, 16 Oct 2019 22:19:29 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392751AbfJPLTW (ORCPT ); Wed, 16 Oct 2019 07:19:22 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:40233 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392705AbfJPLTU (ORCPT ); Wed, 16 Oct 2019 07:19:20 -0400 Received: from [213.220.153.21] (helo=localhost.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1iKhKo-0003tb-R7; Wed, 16 Oct 2019 11:19:18 +0000 From: Christian Brauner To: christian.brauner@ubuntu.com Cc: ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, kafai@fb.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, yhs@fb.com, Aleksa Sarai Subject: [PATCH bpf-next v4 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Date: Wed, 16 Oct 2019 13:18:09 +0200 Message-Id: <20191016111810.1799-3-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016111810.1799-1-christian.brauner@ubuntu.com> References: <20191016034432.4418-1-christian.brauner@ubuntu.com> <20191016111810.1799-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In v5.4-rc2 we added a new helper (cf. [1]) copy_struct_from_user(). This helper is intended for all codepaths that copy structs from userspace that are versioned by size. bpf_prog_get_info_by_fd() does exactly what copy_struct_from_user() is doing. Note that copy_struct_from_user() is calling min() already. So technically, the min_t() call could go. But the info_len is used further below so leave it. [1]: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper") Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Aleksa Sarai Cc: bpf@vger.kernel.org Signed-off-by: Christian Brauner --- /* v1 */ Link: https://lore.kernel.org/r/20191009160907.10981-3-christian.brauner@ubuntu.com /* v2 */ Link: https://lore.kernel.org/r/20191016004138.24845-3-christian.brauner@ubuntu.com - Alexei Starovoitov : - remove unneeded initialization /* v3 */ Link: https://lore.kernel.org/r/20191016034432.4418-3-christian.brauner@ubuntu.com unchanged /* v4 */ - Alexei Starovoitov : - move misplaced min after copy_struct_from_user() --- kernel/bpf/syscall.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8d112bc069c0..d554ca7671b6 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2304,21 +2304,18 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, union bpf_attr __user *uattr) { struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info); - struct bpf_prog_info info = {}; + struct bpf_prog_info info; u32 info_len = attr->info.info_len; struct bpf_prog_stats stats; char __user *uinsns; u32 ulen; int err; - err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len); + err = copy_struct_from_user(&info, sizeof(info), uinfo, info_len); if (err) return err; info_len = min_t(u32, sizeof(info), info_len); - if (copy_from_user(&info, uinfo, info_len)) - return -EFAULT; - info.type = prog->type; info.id = prog->aux->id; info.load_time = prog->aux->load_time; From patchwork Wed Oct 16 11:18:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 1177808 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ubuntu.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 46tVF34HQMz9sCJ for ; Wed, 16 Oct 2019 22:19:35 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392731AbfJPLTV (ORCPT ); Wed, 16 Oct 2019 07:19:21 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:40236 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392706AbfJPLTV (ORCPT ); Wed, 16 Oct 2019 07:19:21 -0400 Received: from [213.220.153.21] (helo=localhost.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1iKhKp-0003tb-89; Wed, 16 Oct 2019 11:19:19 +0000 From: Christian Brauner To: christian.brauner@ubuntu.com Cc: ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, kafai@fb.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, yhs@fb.com, Aleksa Sarai Subject: [PATCH bpf-next v4 3/3] bpf: use copy_struct_from_user() in bpf() syscall Date: Wed, 16 Oct 2019 13:18:10 +0200 Message-Id: <20191016111810.1799-4-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016111810.1799-1-christian.brauner@ubuntu.com> References: <20191016034432.4418-1-christian.brauner@ubuntu.com> <20191016111810.1799-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In v5.4-rc2 we added a new helper (cf. [1]) copy_struct_from_user(). This helper is intended for all codepaths that copy structs from userspace that are versioned by size. The bpf() syscall does exactly what copy_struct_from_user() is doing. Note that copy_struct_from_user() is calling min() already. So technically, the min_t() call could go. But the size is used further below so leave it. [1]: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper") Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Aleksa Sarai Cc: bpf@vger.kernel.org Signed-off-by: Christian Brauner --- /* v1 */ Link: https://lore.kernel.org/r/20191009160907.10981-4-christian.brauner@ubuntu.com /* v2 */ Link: https://lore.kernel.org/r/20191016004138.24845-4-christian.brauner@ubuntu.com - Alexei Starovoitov : - remove unneeded initialization /* v3 */ Link: https://lore.kernel.org/r/20191016034432.4418-4-christian.brauner@ubuntu.com unchanged /* v4 */ - Alexei Starovoitov : - move misplaced min after copy_struct_from_user() --- kernel/bpf/syscall.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index d554ca7671b6..47bf4a81002d 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2812,21 +2812,18 @@ static int bpf_task_fd_query(const union bpf_attr *attr, SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) { - union bpf_attr attr = {}; + union bpf_attr attr; int err; if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN)) return -EPERM; - err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size); + /* copy attributes from user space, may be less than sizeof(bpf_attr) */ + err = copy_struct_from_user(&attr, sizeof(attr), uattr, size); if (err) return err; size = min_t(u32, size, sizeof(attr)); - /* copy attributes from user space, may be less than sizeof(bpf_attr) */ - if (copy_from_user(&attr, uattr, size) != 0) - return -EFAULT; - err = security_bpf(cmd, &attr, size); if (err < 0) return err;