From patchwork Mon Dec 16 22:24:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Casey Schaufler X-Patchwork-Id: 11295775 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D6D9A138D for ; Mon, 16 Dec 2019 22:27:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB32522464 for ; Mon, 16 Dec 2019 22:27:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="lXU0Lkbd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727843AbfLPW12 (ORCPT ); Mon, 16 Dec 2019 17:27:28 -0500 Received: from sonic306-28.consmr.mail.ne1.yahoo.com ([66.163.189.90]:44395 "EHLO sonic306-28.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727977AbfLPWZx (ORCPT ); Mon, 16 Dec 2019 17:25:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1576535151; bh=pk4OM2anm1/C+LQ96dtDYWeHAfHr5wLruGqEfoA0KyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject; b=lXU0LkbdrESxOfrdn4xmp5qGdHpGX4r42WOcujBm8skPdlVpu6iOVjfUYe4P2hKnoFpKbRobMCBQ2qb8+sw7QoA2WkPDMI77I4UDX6wMs5FQFO7KjcQCgvBUWaFJe9OiJtlcTL4cFz6LtVVrh1WtrhXAL/OPQljDzqixIEL1VghF2iI0keGKGVNjEcAOB7ixg51hQXqLopiOrUTxtaLq8J0nnE2kck+Dmf9tBkheEHgJbav5ixwfj8pEdUKYJTooWe1toN8qT3SwFHS0WHD+7kxmlUOrGaoFkpJrSGP77o98moDQma+LEKlhDKw94IgrZ4iC612dkgXwPnHDmeZSkw== X-YMail-OSG: EOSHJDsVM1mOhuYYPl_cXXeuHvFRJU87DA6RKtOoGHz9wDxfoiIVSe9C2nQM1Fw lc_9Jru.i.LZn6UL1P3qv6mL4TiL5NsTIKukqPSzZGS1j_LEjNdAej2V9E.jeuHWfo_3eob98pc8 6VyNqzUjbCiCnBkT4fFuBzC.rwWsY4x.EiFGY5fjWZG3BrRBnPvQRgVtdsrb5PjyUEVEmZg7fvbQ YhfobkW34KyBQ4sWo.GPwD4rp21ezmv9pFU8D4.lLx8Ls88UjeT93CszjV9e5u97NTF1GwHC0aGH iO.l2XUSdP.ifRSHbznvErL6RWmB3H9ClY9WK1eJteatiOek1cdiBT6MZcXMGa_EZqPyzAD6qnWs _oNUYwT5pMGxwBU5p872niiaz8EnxZKbeaE3hZqPqnH8En6rLE.kRwh4Y.bGKy1cHYz5Mbk2kPU5 6UmZPGTlAKovFa2vvyBWDhRE.3h18n2xYy3ndJDHPWXJz.xG0lI4yURA_DHA_rYFz6Ed94xyCPPn g6hz96Ae4LtJPOpR7KcmW3uIOJrjJ4SpQGpB0Ks21gvZx4KAUIs7QEyn.aJT1yBSmi.K2H9.vhhK i_yw6Si3QdnuF6j9Jqor.jlx25DVXPH73XmDyNLEAlk9yoKnqC3.G9xxfSKIkhhZLeAQ_MdIjHHy VYr5w.V9QTt8hAJ_M64YhYh_UKkPVPvKQR77lHqauzjyKQz4Zu29qdAhZx7YJY1KUz_Oe8QVYAwm wGtl4N1A6fpcLbv8b3BNAWMh3tImLz491q4IYUNyOaq0bUT0v0lIU6PTvoIpWoGtLcmfhDjOoC6N sVtkj24dmoQws_EZ_74qRz1WTSoXnnecPe6MZSyCS3ROC3cOq4gYzMZwPPitOGfmTHjUHoYaxMVD 8Tp2i4aDIQfJADCaRB05TsfzSZ47j5QvMwSrrnEDCF76dRhMURGGP1zplFRryMfxuW1P3bBftume cFSi0mGNOj45RnDUcjznlTAXu9i62AuQsbcxBQ.lg7NoiQlxZ1gQzBaA2lNOZPlLF9MdIIUE3jay oLNvbuK9l2zi7N6FYMyBpMiicuGny1ly04nTr9WzVpj2z8.99XoK55smyAvFylnHRi9EhLAnYiOO 7RnTsR9C4hd5sfYUIKRkhR2rLOFn2aKN8knrGOVu0t6xbgTW1eCxgyOsAZUiG1Wz7yis0TLPtW79 .u4DpiU0Skz6HLNf2DprE2sWJfPKQaaivVwG.6_xPDMcQHe1_w32jG1B0uPNc0K18cvRtIX6Qf9Z x3PfK7qXCXecGJpnwPyVWD9qqwD58N7mCrsPXI1tKTusQ2P_gJ0TY6rVgFyagohtFX0u.EMXSiLW xDjgkjpt_ecXNclidtpB3MemAhi7CboTpov_RvT03ytp3ZIAbsP2YVEn21uK3RFSzHg9FMKW12oG 3FQ4HgN53jjeMknrkXkm01qk5ZCzWHu0L0hVPzgX1v3h6WVbOQlPkUcyXT2J7wmwF Received: from sonic.gate.mail.ne1.yahoo.com by sonic306.consmr.mail.ne1.yahoo.com with HTTP; Mon, 16 Dec 2019 22:25:51 +0000 Received: by smtp426.mail.gq1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID ad449dcdff93ede6e1b6227b68a93c45; Mon, 16 Dec 2019 22:25:46 +0000 (UTC) From: Casey Schaufler To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov Subject: [PATCH v12 16/25] LSM: Use lsmcontext in security_dentry_init_security Date: Mon, 16 Dec 2019 14:24:22 -0800 Message-Id: <20191216222431.4956-17-casey@schaufler-ca.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191216222431.4956-1-casey@schaufler-ca.com> References: <20191216222431.4956-1-casey@schaufler-ca.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Change the security_dentry_init_security() interface to fill an lsmcontext structure instead of a void * data area and a length. The lone caller of this interface is NFS4, which may make copies of the data using its own mechanisms. A rework of the nfs4 code to use the lsmcontext properly is a significant project, so the coward's way out is taken, and the lsmcontext data from security_dentry_init_security() is copied, then released directly. This interface does not use the "display". There is currently not case where that is useful or reasonable. Reviewed-by: Kees Cook Reviewed-by: John Johansen Signed-off-by: Casey Schaufler --- fs/nfs/nfs4proc.c | 26 ++++++++++++++++---------- include/linux/security.h | 7 +++---- security/security.c | 29 +++++++++++++++++++++++++---- 3 files changed, 44 insertions(+), 18 deletions(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index a30e36654c57..78d63f7f0088 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -112,6 +112,7 @@ static inline struct nfs4_label * nfs4_label_init_security(struct inode *dir, struct dentry *dentry, struct iattr *sattr, struct nfs4_label *label) { + struct lsmcontext context; int err; if (label == NULL) @@ -121,21 +122,26 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry, return NULL; err = security_dentry_init_security(dentry, sattr->ia_mode, - &dentry->d_name, (void **)&label->label, &label->len); - if (err == 0) - return label; + &dentry->d_name, &context); + + if (err) + return NULL; + + label->label = kmemdup(context.context, context.len, GFP_KERNEL); + if (label->label == NULL) + label = NULL; + else + label->len = context.len; + + security_release_secctx(&context); + + return label; - return NULL; } static inline void nfs4_label_release_security(struct nfs4_label *label) { - struct lsmcontext scaff; /* scaffolding */ - - if (label) { - lsmcontext_init(&scaff, label->label, label->len, 0); - security_release_secctx(&scaff); - } + kfree(label->label); } static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label) { diff --git a/include/linux/security.h b/include/linux/security.h index 00421941f683..a5eba06a9382 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -398,8 +398,8 @@ int security_add_mnt_opt(const char *option, const char *val, int len, void **mnt_opts); int security_move_mount(const struct path *from_path, const struct path *to_path); int security_dentry_init_security(struct dentry *dentry, int mode, - const struct qstr *name, void **ctx, - u32 *ctxlen); + const struct qstr *name, + struct lsmcontext *ctx); int security_dentry_create_files_as(struct dentry *dentry, int mode, struct qstr *name, const struct cred *old, @@ -790,8 +790,7 @@ static inline void security_inode_free(struct inode *inode) static inline int security_dentry_init_security(struct dentry *dentry, int mode, const struct qstr *name, - void **ctx, - u32 *ctxlen) + struct lsmcontext *ctx) { return -EOPNOTSUPP; } diff --git a/security/security.c b/security/security.c index 4ba1a6ed36e0..8aa107b57af9 100644 --- a/security/security.c +++ b/security/security.c @@ -1011,12 +1011,33 @@ void security_inode_free(struct inode *inode) inode_free_by_rcu); } +/* + * security_dentry_init_security - initial context for a dentry + * @dentry: directory entry + * @mode: access mode + * @name: path name + * @context: resulting security context + * + * Use at most one security module to get the initial + * security context. Do not use the "display". + * + * Returns -EOPNOTSUPP if not supplied by any module or the module result. + */ int security_dentry_init_security(struct dentry *dentry, int mode, - const struct qstr *name, void **ctx, - u32 *ctxlen) + const struct qstr *name, + struct lsmcontext *cp) { - return call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode, - name, ctx, ctxlen); + struct security_hook_list *hp; + + hlist_for_each_entry(hp, &security_hook_heads.dentry_init_security, + list) { + cp->slot = hp->lsmid->slot; + return hp->hook.dentry_init_security(dentry, mode, name, + (void **)&cp->context, + &cp->len); + } + + return -EOPNOTSUPP; } EXPORT_SYMBOL(security_dentry_init_security);