From patchwork Fri Apr 19 00:45:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Casey Schaufler X-Patchwork-Id: 10908543 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 327281515 for ; Fri, 19 Apr 2019 00:49:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1C7AE28B1F for ; Fri, 19 Apr 2019 00:49:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0E98828B9D; Fri, 19 Apr 2019 00:49:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 88AF628B1F for ; Fri, 19 Apr 2019 00:49:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727059AbfDSAtK (ORCPT ); Thu, 18 Apr 2019 20:49:10 -0400 Received: from sonic317-33.consmr.mail.bf2.yahoo.com ([74.6.129.88]:44917 "EHLO sonic317-33.consmr.mail.bf2.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727054AbfDSAtJ (ORCPT ); Thu, 18 Apr 2019 20:49:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1555634948; bh=d5byK4DqcfIbnPzz1tahUCb++vs0/VJdTyNADlEhXIU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject; b=BJpwsZVIvYS9aYB03aAKhjPXSzNKLWdN/On8bVn3ODMBJIKo4BlAcycNsHCtArTR/xQoMGZWfGntxEw0dzOtYNOgTXn7mLCGM51xvfdGvBAoZ0w+kWk3jnEYklec6BMQT+zTi01tqg4+uTSfusU9g33aBju1d8YRs6rx3xnhhd6p4i7abV5+FHmRrIuMO34FhTt6OB9sjGeNvdYjd8l+elJsaG/hi+Rw9SfUsTDH2eJoTVL7/x5rhDp5CwvLhOSFm8rfR9HaoKRh008VuYaq/mxaq4YEXRpNf7CmVRSKIAfZhGmbpwWtlFiciI61F1bJ1ejzDerXCr6sINCvSMl6rg== X-YMail-OSG: MOU0_ZIVM1kNMn74rzxah3yXPnQ.Fr_ruvhCE5lG1wLRMGWo9qL.aPv9mTEgkSF eMauBQEMj10DoiR8hsrcySZJaxNqlnOGK4FG00jIqJhEEfkfxYpxZmHmfXcQIxdjeziHp2dH17Uh XymZCnxE53VwSMgNMWBVRFgVsCCx3qprglxMtuTiRCEFp2GrcbM4Y.F0Y_TMmhSlaEyqmohAp8Zf QSr.CuZFkOP_N7xvTQ7U1wlWOJ0Az4RgS4mZh_VkQ2p_v2g6wwhfquieEzBpyPTsegwA6SJVyS.c IbuMgR7RvvEemDv2FUjISTrVAuE3txP6I.o6HDZybDKz6NqeTLO1SnbM0438EGuwgT5wu1JkdZ5P s1Cayvp7s7nuT74QbLimAOQC7unD_na.Hae1_lx2gx.cql3xsrTt2Urv3sw2EdJAjYHxQenbPMp4 kTBsvqGVpPWmWzliu1K3PT5q3DMmCvg1ACiPvkYhx8L_iCiyBAMcruqq.RPHx_iJYNGBbYPOmdFg AcltW2f7V6yiQiZcADz0MsCuuGqYoAOIsYKQtk0ZnvQOqLPvKJxMYfqedg6V2dYmSSOKw_sW69dA nuzQBljEVnGvM7r2F6MegmALgb.ryo5e9kCWlG81uNKVwcOPME30Mr.E5wCiJtwuMATMF1aT1PlO PYTyoH.xn4e0BzXF.roXuXD04gYMZVVoxRdJoqOQ6LUgEvLIRnGgny3bv1PyIIzD67u7XI6N3wb6 vL7GIpDndAjx5Q3xCZLZoCP8V7ikA9YrPpto3U6eUjHYgAE9hgNC5a6RsIyTj2wbJhFdRJ9bWFoe sKsD26yzz7E_rVB1xenyfwfUtWVyoAJrc0NQGu1QWFn.rhpBpTgE9jveshorbZKgvcK8uQ0VPNNE eL.qTGr7LdNmizLemcIs_b65rgDYEdO_cJqzpEoTLmAi0HwrOO2MFNxf3EPRRqu4jM0CQjaFit10 mSyAekJdM4Oq1ruCMoJ.bpiJKb_VpZda3RsbYNbZ68LzAQMNBZ9C1uA9OPNknQJiYd2KJvBSJIEA AGerMHOrlk6LdgUlUXd.J1i3pw4PI7afIl5byFXLAzEwYQ0gXhNGQ4H4TvGAubDAVjyYZyxqTUJy H5wzpJwmV1sDkcwpe_luALHl1HkIgkAgbcjQBIrOwUoQ4oF.PEhfioZ6FFdVCeLbCetI6LfAUEMr Xxq5rKHA6HS29 Received: from sonic.gate.mail.ne1.yahoo.com by sonic317.consmr.mail.bf2.yahoo.com with HTTP; Fri, 19 Apr 2019 00:49:08 +0000 Received: from c-67-169-65-224.hsd1.ca.comcast.net (EHLO localhost.localdomain) ([67.169.65.224]) by smtp419.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 524225efee00edb3a1e75559f6c5c8ed; Fri, 19 Apr 2019 00:49:04 +0000 (UTC) From: Casey Schaufler To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: casey@schaufler-ca.com Subject: [PATCH 70/90] LSM: Correct handling of ENOSYS in inode_setxattr Date: Thu, 18 Apr 2019 17:45:57 -0700 Message-Id: <20190419004617.64627-71-casey@schaufler-ca.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20190419004617.64627-1-casey@schaufler-ca.com> References: <20190419004617.64627-1-casey@schaufler-ca.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP The usual "bail on fail" behavior of LSM hooks doesn't work for security_inode_setxattr(). Modules are allowed to return -ENOSYS if the attribute specifed isn't one they manage. Fix the code to accomodate this unusal case. This requires changes to the hooks in SELinux and Smack. Signed-off-by: Casey Schaufler --- security/security.c | 28 ++++++++++++++-------------- security/selinux/hooks.c | 7 ++----- security/smack/smack_lsm.c | 10 +++++----- 3 files changed, 21 insertions(+), 24 deletions(-) diff --git a/security/security.c b/security/security.c index 05a19b28e105..f1e2ffe81829 100644 --- a/security/security.c +++ b/security/security.c @@ -1341,24 +1341,24 @@ int security_inode_getattr(const struct path *path) int security_inode_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { - int ret; + struct security_hook_list *hp; + int rc = -ENOSYS; if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) return 0; - /* - * SELinux and Smack integrate the cap call, - * so assume that all LSMs supplying this call do so. - */ - ret = call_int_hook(inode_setxattr, 1, dentry, name, value, size, - flags); - if (ret == 1) - ret = cap_inode_setxattr(dentry, name, value, size, flags); - if (ret) - return ret; - ret = ima_inode_setxattr(dentry, name, value, size); - if (ret) - return ret; + hlist_for_each_entry(hp, &security_hook_heads.inode_setxattr, list) { + rc = hp->hook.inode_setxattr(dentry, name, value, size, flags); + if (rc != -ENOSYS) + break; + } + if (rc == -ENOSYS) + rc = cap_inode_setxattr(dentry, name, value, size, flags); + if (rc) + return rc; + rc = ima_inode_setxattr(dentry, name, value, size); + if (rc) + return rc; return evm_inode_setxattr(dentry, name, value, size); } diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index af0d98f4dd37..17ba47f9f4e2 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3097,13 +3097,10 @@ static int selinux_inode_setxattr(struct dentry *dentry, const char *name, int rc = 0; if (strcmp(name, XATTR_NAME_SELINUX)) { - rc = cap_inode_setxattr(dentry, name, value, size, flags); - if (rc) - return rc; - /* Not an attribute we recognize, so just check the ordinary setattr permission. */ - return dentry_has_perm(current_cred(), dentry, FILE__SETATTR); + rc = dentry_has_perm(current_cred(), dentry, FILE__SETATTR); + return rc ? rc : -ENOSYS; } sbsec = selinux_superblock(inode->i_sb); diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index d76aa0fc37a4..0e2f68e5b895 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1281,7 +1281,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0) rc = -EINVAL; } else - rc = cap_inode_setxattr(dentry, name, value, size, flags); + rc = -ENOSYS; if (check_priv && !smack_privileged(CAP_MAC_ADMIN)) rc = -EPERM; @@ -1295,11 +1295,11 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, rc = -EINVAL; } - smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); - smk_ad_setfield_u_fs_path_dentry(&ad, dentry); - if (rc == 0) { - rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad); + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); + smk_ad_setfield_u_fs_path_dentry(&ad, dentry); + rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), + MAY_WRITE, &ad); rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc); }