From patchwork Mon Dec 16 22:36:12 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Casey Schaufler X-Patchwork-Id: 11296119 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 D35AC138D for ; Mon, 16 Dec 2019 22:37:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B13A421835 for ; Mon, 16 Dec 2019 22:37:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="e8/MEWXm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727740AbfLPWh4 (ORCPT ); Mon, 16 Dec 2019 17:37:56 -0500 Received: from sonic306-28.consmr.mail.ne1.yahoo.com ([66.163.189.90]:32990 "EHLO sonic306-28.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727644AbfLPWh4 (ORCPT ); Mon, 16 Dec 2019 17:37:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1576535874; bh=pk4OM2anm1/C+LQ96dtDYWeHAfHr5wLruGqEfoA0KyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject; b=e8/MEWXmiX0PDwzcd5hoqxf6uXdNXWOi2NDRqIDSDrB8m2yYtGMsIqeMg/S/+K7zkAWxzXArZOCV/clbRwJyvdbr2zM8zlJ65/Vg7Hvx7Ae3UcaJomInM+N9059zHZUylwrvJj7O+0pJ9yg8VxVcMiG1egcPizr+Prd2RmE/OY6Q9mIXUVmCqPzNdTxj0Spc/LZDet2cAsMLj/+AFog9tu5ck6QD4RoBMV2y115Pdc8KYUZy9WLbfJxKrJPQssh/ATOx6OnynS3JhpQe+LXEjcdmMNRODrgg9zEiT5QIiIwxaOZTauwCV5xiONHfjKjPwfE9FHb+l8dsEkPOYOxheg== X-YMail-OSG: dukP4mQVM1kn4ZkTV2KsZ6WYDM6xdkMJ4h2VJ34HZTSMmlcITKyX1ATAGNPUKjl wrJ2JWh79ut1IqKcYavXH9puiIUPUtM3HHJlgtKPMuvDjv7UpEVYG4gkT2xpdjwwY4LPVIaNnz8b P8Tb4Y6pbkFFUBYzxIpXxQUPYTdl1LrBNlgp_Z6oF9r1SrlxquHWYmz2hZaXMndV7MFmetz3Fi1y YiwamyQ0TMnMxzxM8kjtMFQJT.aPZZ1r6rx5YogeQRvvSkaU_KI2R9IWfkmVNYFrwN19e7X2BcWy H5vGfD_HUYAcudsj6kGZbltyZ5hQgJ30BYGN.SNQ2EjItftMqrQIABqSkfbEd6Vym7mu93jSTtjv ijPSoU1A.GzUBtCy4yV2WqpiNNgMdxwmrg6axK1yJebzoOSqNywD97y6Gi2yBZDzTtClnUS_PZ9Q jTmJqlVzudQxmC24Ypvp9qmqr06d5tpxCtBlCIOGk8mxz0JWfKzdXI7f.717s7XE5lMoqTuE_oMZ J0OGvn77066F2_XS5iBlZQWeX93lGPrU74k.aaLthsl8qV.a_8UVTa2S6hnuZG27CMari.7bjjpe 45NxJ9.ObyThP92aduO5.DAQmojFNO23VopdOhKv_WRyj0aDiVAeI24Ljaqm51pY8IbI4MMNAj_d iUBJwM4uQU77QdNB41b_shvSJWZ4XuKURTlC6LYLoZ47yedrRuudEx_Xql.eJBPp48JwBAYgNdqA WJcnCpUVIMnsJ21VV3ExA50R738awEIl4bEU.lu2gVkIYL3Ddmuf85ezog7cMOS8N66TLGrEbg8Z MGz_OWivngLpxL2w4PM9ahXUmC.JvA4q5AMALzMaQsDuDOE5KAKNlpq8jQvf2OPugIYFEyEpBogV xafrZtfh1FxK49EP2MWwVDa_Nqm6gsseCed7y6qr9xUBtbNIChn5wwNsiazOypQKCJwNoYyvSgy6 tVkGUjVEm_OXIOQJCd0IOV4KWKMkEMTKVC8t1_ZPaMlVuQeXbzkxN_NGpJH.ONVCpZi1I_nuGT2g eAXRXxKs6k8rY.IFywnY4S7yq.V6ARcYCNu1PifKfTfrRqZoMyIz8qzGIEggf76Zfhx_8Ixqqdre O7X5dsHzehV7Tcp4RkwCcSHJ7zE7aAy4IT6191ifnsrrLqAvTaR1.lr6yjMQDd3wYvHSjvodf.G4 uhNfVgT5sDzYox.lxlNPbLzPJZqaPMivZmI5cWqzCOqxuJ3sPFosSTWSODcdIKHDZZOZTyB3dj6S .GuZOgjWkEnQ44lPbPs0sBS2vUQDTxNulz.v6GdiW2u6xBYQt2LlRJi_498eRcIviVGfU.zgkhtc BJP60DpeH4b8Z20QfCFfZslyniIqqrCNRuH.rA.EtEwhZRiGaChoUeEsN6aQOru96k0G2Bg41D3N MMxfE8.InLYf65Yv6uVMrAozHCRPem04446VAUz5IsJpcApnpQwN1Wd0jzruPpwfaFx4- Received: from sonic.gate.mail.ne1.yahoo.com by sonic306.consmr.mail.ne1.yahoo.com with HTTP; Mon, 16 Dec 2019 22:37:54 +0000 Received: by smtp425.mail.ne1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 8f9d0f9ff5e2996a72ce7cd8024969ae; Mon, 16 Dec 2019 22:37:52 +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 14:36:12 -0800 Message-Id: <20191216223621.5127-17-casey@schaufler-ca.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191216223621.5127-1-casey@schaufler-ca.com> References: <20191216223621.5127-1-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);