From patchwork Wed Nov 13 18:19:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Casey Schaufler X-Patchwork-Id: 11242559 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 28BBA138C for ; Wed, 13 Nov 2019 18:20:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8581206E1 for ; Wed, 13 Nov 2019 18:20:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="pPLTKrVh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728401AbfKMSU6 (ORCPT ); Wed, 13 Nov 2019 13:20:58 -0500 Received: from sonic306-27.consmr.mail.ne1.yahoo.com ([66.163.189.89]:41490 "EHLO sonic306-27.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728325AbfKMSU6 (ORCPT ); Wed, 13 Nov 2019 13:20:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1573669257; bh=5a1Bn2oGXej0Jcc78dgWtIiwCtWaGO4LPz5VJ3J/aYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject; b=pPLTKrVhj3MDhcoDIWNCzjEitUVnKPGKO1K4zPjpd7N0SGb/OmeW1AfExdubMoyI2OFNGtThO+cSRxfCUvkggUhzGOjbP/IRn5xWaXeJTaQzaZth4CgA/h1/SW/+i+fPu7SITk1eCkH5kazBUhqaS2GnhQdND+2S3i4CK9RtTPkgB9J8NBXYM6H/8kY1/rQJJz0fWsJBlSnBmgUn38+JjAKIWj4rKghrmMoVVyDjZenQlVm54NIQZKBKOa+ApX6xey4A3VFQebUFigwJVThCs3qoUAf6UsEvaOSTZGT29WKO0wTRWyfWtjqbClvBGNS4JsqcQpgLriQamTBw2DFkDg== X-YMail-OSG: dlUkSZQVM1kXXZfGh_p5ZV2TozbIXjYq0Hg.Z71Rk8BHcMfr9tuTOX50cngrwhi GLtPjHpqiSIkAvx8XFfIiClPZuuvZ9.r.tXh0GEtY0bdOpqBq.j774YAdxI8ynN1UYJfaDq7mBaY ZYGlqpb_Ut8.fh6Flh0fDyc9SCP6eT53hTLV4nTw5Wfj6qGPOaR6YgJY8A_iP8F4L3xIpFAB2r3y c5lQET3cJxZMdLlwIeuhEI4xHQvnjCnPi0LmljELae4egLMy.HeVRmX1mxLig3_SbskDhSQUPkpB vIKkpg0szy5U3eKJMj9kl137sqCarfweVwHUDswqYpa9EeZF4x.W2.R9nK2ClgkMe8dQUZKyNJ9R nbAQKhKmrEtQsyh6hOboZev7CWpWSgkKXFCEBjGeaIraWQ9NGOKK.oAcURQTZH2iPKsU28denXxP kP6cr0_toqwBEHAnNoSucjg6RZxBxKoo_XoOyf2t7_UtDJG6.Q_RX88BJ2Tphx1JALbsq0BZ8ZVv oSOD_Ps_dZqA0gmyFwu91AKmE_D6f2jAQVVCaiBrrG2gtU9pFVNSXtfacFXGDj1UHrVSdtuHpEKc imW4Srg.xssvZ2.94jTqY_ItiV1o8jF9rkxOdyM2irAUZPSAbcU2Yz.teaJZsbNuHLG.zCZ_Uq7m roZmYX9dT_nDdrJ49JNKiRYALhmWajYUd4WyXqTzzm0k5ono3817XJKkZislN1NHKG9JniOhcslc jwuWLT4SZpS7ucSQwAv3lfXumsl.CsqpI3muhORrYM16nion6fZIIfSl1M59I649r_w_RzS3SkHK 6bHCmNtnchgtNYJCMqRHfi9qHbS0MDBGFczYIt.eLp9GYL3Wvu4uCIDtrRCMeGak6w9DOJXRfcFw RjG0F1CRULVZS6K6IqLGdpa8zQfwZrnoVs5.KfTEtMPaQWli98Gy4Du1DqmO9myWsikGDjl3jJL8 0GOHb8RFRkbzPdPJ70TzfSWZK26r50yrdvwYC1cfk8ND4rB.bxJvcUIah5yv5SCFjTpcWNANuNbt YM43qDzUfy3O6NvMsHs5SUOkR3FUoUH6B4PzInYcUytX2.npntRbHT.hlgfTvNqJ4LnZQ6Ro52Ua Visvs3t0PI_1wt8sofq1JnIY7cx8KFR6ZH5.mjJz30IBxWXptY0nBxkmerfCWFxgPgq4hzKczMA5 ZVk4.7smqgngsXONC3MAqyXf4eg6r_X7irUhuv5afBU3SUJKpjEIHyMtHKbAI.DYUm1bwoRMvK7a yOhCVFHmrDKh63TrG9Q97m9d1AQmRikZsPHLiBJfWMA2.PtzlZ_2Tz_RI7BZ1P230hlKR6VgPh6f caIiX18HtPa25Zm0EFcXHWiR4gNO6dlvBfUBmRp1ERbEDZbk8Q.pS2JPXlyQwMdj_mwWrpyp.sA8 lNZVZv9c3dDUCO7y_G0.hJtYJCVJLWQBcbsRkVszdK5udnIaGasWjnZDGv27LmYtB2sA- Received: from sonic.gate.mail.ne1.yahoo.com by sonic306.consmr.mail.ne1.yahoo.com with HTTP; Wed, 13 Nov 2019 18:20:57 +0000 Received: by smtp405.mail.gq1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 2a1c85ac4bdbf5da4ba3fd738885b7e0; Wed, 13 Nov 2019 18:20:52 +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 v11 16/25] LSM: Use lsmcontext in security_dentry_init_security Date: Wed, 13 Nov 2019 10:19:16 -0800 Message-Id: <20191113181925.2437-17-casey@schaufler-ca.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191113181925.2437-1-casey@schaufler-ca.com> References: <20191113181925.2437-1-casey@schaufler-ca.com> MIME-Version: 1.0 Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org 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 Acked-by: John Johansen --- 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 74e9f4b7cc07..2f76741ee528 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -113,6 +113,7 @@ 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) @@ -122,21 +123,26 @@ 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 e47cef3d62f0..3e333104720d 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -396,8 +396,8 @@ 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, @@ -788,8 +788,7 @@ 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 618d4f90936b..6f43dafe1249 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);