From nobody Sat Feb 7 19:41:25 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 645EEEB64DD for ; Wed, 5 Jul 2023 06:33:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231654AbjGEGda (ORCPT ); Wed, 5 Jul 2023 02:33:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231532AbjGEGdZ (ORCPT ); Wed, 5 Jul 2023 02:33:25 -0400 Received: from mail-vk1-xa2d.google.com (mail-vk1-xa2d.google.com [IPv6:2607:f8b0:4864:20::a2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AD50171B for ; Tue, 4 Jul 2023 23:33:21 -0700 (PDT) Received: by mail-vk1-xa2d.google.com with SMTP id 71dfb90a1353d-4716e4adb14so1831274e0c.0 for ; Tue, 04 Jul 2023 23:33:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1688538800; x=1691130800; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=W+MSmdpLaQYcYfYw7xJr5lmjiO0vLCrOZIxlLos01I4=; b=bFlmbiX7I0IMNBN+awjy44Gd2HHxolAdFzcioJ6vbbxbKEhkdrQChkaBrAG9TgBfKT x0Z2gtzkhzO55v/fQhqA0JPCBoHFOFGB4fsAyofg2LzDmXjriBm2FqrokpTc7btoXEHH bLA19vYllamBMyiqrr9cjjjuZUbPI0WKT4WEE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688538800; x=1691130800; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=W+MSmdpLaQYcYfYw7xJr5lmjiO0vLCrOZIxlLos01I4=; b=HEByHiQyCiKP+NeE37geXYI3Qu/YXsL953WZZHknHafUDaZE0wDR8mGpLrdPxW4L2e Ju4F352/4nOGqHXD06zOUdsNy+SMjqYNk5ichcHMF4ratt9X2EYBS0TfiHezbezpusVR oanM45bZD7yBF3UxpQYBEnLjRH0VOQtRkrdlsNrNnK08TawR9qn9s0pR7IXu//w6qN+k XG8VLkyOs1yn+pp60yeDqjFINlsPRLRZ6dYLPzDyhtrxTtCieVvAqmjQp5oMd3KDajPz 7sWfWDADzN2QTjakqbxeNdfsE11d/IwMFfgUDntvSHyjai9MtLvlWVIAyAnZWlCaSSbV ZprQ== X-Gm-Message-State: ABy/qLZJY1nuwYozVViRPE7TTRs4SRptdryl0gCmEiq8AjGq7fB93N0C ydXq1Eu7DbtlmNDzCZIlsUOP7Q== X-Google-Smtp-Source: APBJJlFcgKaSPJKkbCoS2vIlhS3WYafUAvQl5v36URdmF0hDQjm/PTL88mvcn7PB87UgQocXD3sayA== X-Received: by 2002:a05:6122:2af:b0:46e:6af4:3333 with SMTP id 15-20020a05612202af00b0046e6af43333mr6858407vkq.5.1688538800100; Tue, 04 Jul 2023 23:33:20 -0700 (PDT) Received: from localhost (183.43.230.35.bc.googleusercontent.com. [35.230.43.183]) by smtp.gmail.com with UTF8SMTPSA id bj2-20020a17090b088200b002633fa95ac2sm633631pjb.13.2023.07.04.23.33.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Jul 2023 23:33:19 -0700 (PDT) From: jeffxu@chromium.org To: skhan@linuxfoundation.org, keescook@chromium.org Cc: akpm@linux-foundation.org, dmitry.torokhov@gmail.com, dverkamp@chromium.org, asmadeus@codewreck.org, hughd@google.com, jeffxu@google.com, jorgelo@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, jannh@google.com, linux-hardening@vger.kernel.org, linux-security-module@vger.kernel.org, kernel test robot Subject: [PATCH v2 1/2] mm/memfd: sysctl: fix MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED Date: Wed, 5 Jul 2023 06:33:14 +0000 Message-ID: <20230705063315.3680666-2-jeffxu@google.com> X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog In-Reply-To: <20230705063315.3680666-1-jeffxu@google.com> References: <20230705063315.3680666-1-jeffxu@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Jeff Xu When vm.memfd_noexec is 2 (MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED), memfd_create(.., MFD_EXEC) should fail. This complies with how MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED is defined - "memfd_create() without MFD_NOEXEC_SEAL will be rejected" Fixes: 105ff5339f49 ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC") Reported-by: Dominique Martinet Closes: https://lore.kernel.org/linux-mm/CABi2SkXUX_QqTQ10Yx9bBUGpN1wByOi_= =3DgZU6WEy5a8MaQY3Jw@mail.gmail.com/T/ Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202306301351.kkbSegQW-lkp@int= el.com/ Signed-off-by: Jeff Xu --- mm/memfd.c | 57 +++++++++++++++++++++++++++++++----------------------- 1 file changed, 33 insertions(+), 24 deletions(-) diff --git a/mm/memfd.c b/mm/memfd.c index e763e76f1106..0bdbd2335af7 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -268,6 +268,36 @@ long memfd_fcntl(struct file *file, unsigned int cmd, = unsigned int arg) =20 #define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | MFD= _NOEXEC_SEAL | MFD_EXEC) =20 +static int check_sysctl_memfd_noexec(unsigned int *flags) +{ +#ifdef CONFIG_SYSCTL + char comm[TASK_COMM_LEN]; + int sysctl =3D MEMFD_NOEXEC_SCOPE_EXEC; + struct pid_namespace *ns; + + ns =3D task_active_pid_ns(current); + if (ns) + sysctl =3D ns->memfd_noexec_scope; + + if (!(*flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) { + if (sysctl =3D=3D MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL) + *flags |=3D MFD_NOEXEC_SEAL; + else + *flags |=3D MFD_EXEC; + } + + if (*flags & MFD_EXEC && sysctl >=3D MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) { + pr_warn_once( + "memfd_create(): MFD_NOEXEC_SEAL is enforced, pid=3D%d '%s'\n", + task_pid_nr(current), get_task_comm(comm, current)); + + return -EACCES; + } +#endif + + return 0; +} + SYSCALL_DEFINE2(memfd_create, const char __user *, uname, unsigned int, flags) @@ -294,35 +324,14 @@ SYSCALL_DEFINE2(memfd_create, return -EINVAL; =20 if (!(flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) { -#ifdef CONFIG_SYSCTL - int sysctl =3D MEMFD_NOEXEC_SCOPE_EXEC; - struct pid_namespace *ns; - - ns =3D task_active_pid_ns(current); - if (ns) - sysctl =3D ns->memfd_noexec_scope; - - switch (sysctl) { - case MEMFD_NOEXEC_SCOPE_EXEC: - flags |=3D MFD_EXEC; - break; - case MEMFD_NOEXEC_SCOPE_NOEXEC_SEAL: - flags |=3D MFD_NOEXEC_SEAL; - break; - default: - pr_warn_once( - "memfd_create(): MFD_NOEXEC_SEAL is enforced, pid=3D%d '%s'\n", - task_pid_nr(current), get_task_comm(comm, current)); - return -EINVAL; - } -#else - flags |=3D MFD_EXEC; -#endif pr_warn_once( "memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=3D%d '%s'\n", task_pid_nr(current), get_task_comm(comm, current)); } =20 + if (check_sysctl_memfd_noexec(&flags) < 0) + return -EACCES; + /* length includes terminating zero */ len =3D strnlen_user(uname, MFD_NAME_MAX_LEN + 1); if (len <=3D 0) --=20 2.41.0.255.g8b1d071c50-goog From nobody Sat Feb 7 19:41:25 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9308FC001B3 for ; Wed, 5 Jul 2023 06:33:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231703AbjGEGdk (ORCPT ); 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[35.230.43.183]) by smtp.gmail.com with UTF8SMTPSA id h18-20020a63f912000000b0051b36aee4f6sm17145711pgi.83.2023.07.04.23.33.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Jul 2023 23:33:20 -0700 (PDT) From: jeffxu@chromium.org To: skhan@linuxfoundation.org, keescook@chromium.org Cc: akpm@linux-foundation.org, dmitry.torokhov@gmail.com, dverkamp@chromium.org, asmadeus@codewreck.org, hughd@google.com, jeffxu@google.com, jorgelo@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, jannh@google.com, linux-hardening@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v2 2/2] selftests/memfd: sysctl: fix MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED Date: Wed, 5 Jul 2023 06:33:15 +0000 Message-ID: <20230705063315.3680666-3-jeffxu@google.com> X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog In-Reply-To: <20230705063315.3680666-1-jeffxu@google.com> References: <20230705063315.3680666-1-jeffxu@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Jeff Xu Add selftest for sysctl vm.memfd_noexec is 2 (MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED) memfd_create(.., MFD_EXEC) should fail in this case. Reported-by: Dominique Martinet Closes: https://lore.kernel.org/linux-mm/CABi2SkXUX_QqTQ10Yx9bBUGpN1wByOi_= =3DgZU6WEy5a8MaQY3Jw@mail.gmail.com/T/ Signed-off-by: Jeff Xu --- tools/testing/selftests/memfd/memfd_test.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/sel= ftests/memfd/memfd_test.c index dba0e8ba002f..dbdd9ec5e397 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -1147,6 +1147,11 @@ static void test_sysctl_child(void) sysctl_assert_write("2"); mfd_fail_new("kern_memfd_sysctl_2", MFD_CLOEXEC | MFD_ALLOW_SEALING); + mfd_fail_new("kern_memfd_sysctl_2_MFD_EXEC", + MFD_CLOEXEC | MFD_EXEC); + fd =3D mfd_assert_new("", 0, MFD_NOEXEC_SEAL); + close(fd); + sysctl_fail_write("0"); sysctl_fail_write("1"); } --=20 2.41.0.255.g8b1d071c50-goog