From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D80BC43215 for ; Thu, 21 Nov 2019 19:00:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 008BB206D8 for ; Thu, 21 Nov 2019 19:00:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726880AbfKUTAo (ORCPT ); Thu, 21 Nov 2019 14:00:44 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:59537 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726861AbfKUTAo (ORCPT ); Thu, 21 Nov 2019 14:00:44 -0500 Received: from static-50-53-33-191.bvtn.or.frontiernet.net ([50.53.33.191] helo=[192.168.192.153]) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1iXrh2-000599-Lt; Thu, 21 Nov 2019 19:00:40 +0000 Subject: Re: [PATCH v11 16/25] LSM: Use lsmcontext in security_dentry_init_security To: Casey Schaufler , casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: keescook@chromium.org, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov References: <20191113181925.2437-1-casey@schaufler-ca.com> <20191113181925.2437-17-casey@schaufler-ca.com> From: John Johansen Openpgp: preference=signencrypt Autocrypt: addr=john.johansen@canonical.com; prefer-encrypt=mutual; keydata= xsFNBE5mrPoBEADAk19PsgVgBKkImmR2isPQ6o7KJhTTKjJdwVbkWSnNn+o6Up5knKP1f49E BQlceWg1yp/NwbR8ad+eSEO/uma/K+PqWvBptKC9SWD97FG4uB4/caomLEU97sLQMtnvGWdx rxVRGM4anzWYMgzz5TZmIiVTZ43Ou5VpaS1Vz1ZSxP3h/xKNZr/TcW5WQai8u3PWVnbkjhSZ PHv1BghN69qxEPomrJBm1gmtx3ZiVmFXluwTmTgJOkpFol7nbJ0ilnYHrA7SX3CtR1upeUpM a/WIanVO96WdTjHHIa43fbhmQube4txS3FcQLOJVqQsx6lE9B7qAppm9hQ10qPWwdfPy/+0W 6AWtNu5ASiGVCInWzl2HBqYd/Zll93zUq+NIoCn8sDAM9iH+wtaGDcJywIGIn+edKNtK72AM gChTg/j1ZoWH6ZeWPjuUfubVzZto1FMoGJ/SF4MmdQG1iQNtf4sFZbEgXuy9cGi2bomF0zvy BJSANpxlKNBDYKzN6Kz09HUAkjlFMNgomL/cjqgABtAx59L+dVIZfaF281pIcUZzwvh5+JoG eOW5uBSMbE7L38nszooykIJ5XrAchkJxNfz7k+FnQeKEkNzEd2LWc3QF4BQZYRT6PHHga3Rg ykW5+1wTMqJILdmtaPbXrF3FvnV0LRPcv4xKx7B3fGm7ygdoowARAQABzR1Kb2huIEpvaGFu c2VuIDxqb2huQGpqbXgubmV0PsLBegQTAQoAJAIbAwULCQgHAwUVCgkICwUWAgMBAAIeAQIX gAUCTo0YVwIZAQAKCRAFLzZwGNXD2LxJD/9TJZCpwlncTgYeraEMeDfkWv8c1IsM1j0AmE4V tL+fE780ZVP9gkjgkdYSxt7ecETPTKMaZSisrl1RwqU0oogXdXQSpxrGH01icu/2n0jcYSqY KggPxy78BGs2LZq4XPfJTZmHZGnXGq/eDr/mSnj0aavBJmMZ6jbiPz6yHtBYPZ9fdo8btczw P41YeWoIu26/8II6f0Xm3VC5oAa8v7Rd+RWZa8TMwlhzHExxel3jtI7IzzOsnmE9/8Dm0ARD 5iTLCXwR1cwI/J9BF/S1Xv8PN1huT3ItCNdatgp8zqoJkgPVjmvyL64Q3fEkYbfHOWsaba9/ kAVtBNz9RTFh7IHDfECVaToujBd7BtPqr+qIjWFadJD3I5eLCVJvVrrolrCATlFtN3YkQs6J n1AiIVIU3bHR8Gjevgz5Ll6SCGHgRrkyRpnSYaU/uLgn37N6AYxi/QAL+by3CyEFLjzWAEvy Q8bq3Iucn7JEbhS/J//dUqLoeUf8tsGi00zmrITZYeFYARhQMtsfizIrVDtz1iPf/ZMp5gRB niyjpXn131cm3M3gv6HrQsAGnn8AJru8GDi5XJYIco/1+x/qEiN2nClaAOpbhzN2eUvPDY5W 0q3bA/Zp2mfG52vbRI+tQ0Br1Hd/vsntUHO903mMZep2NzN3BZ5qEvPvG4rW5Zq2DpybWc7B TQROZqz6ARAAoqw6kkBhWyM1fvgamAVjeZ6nKEfnRWbkC94L1EsJLup3Wb2X0ABNOHSkbSD4 pAuC2tKF/EGBt5CP7QdVKRGcQzAd6b2c1Idy9RLw6w4gi+nn/d1Pm1kkYhkSi5zWaIg0m5RQ Uk+El8zkf5tcE/1N0Z5OK2JhjwFu5bX0a0l4cFGWVQEciVMDKRtxMjEtk3SxFalm6ZdQ2pp2 822clnq4zZ9mWu1d2waxiz+b5Ia4weDYa7n41URcBEUbJAgnicJkJtCTwyIxIW2KnVyOrjvk QzIBvaP0FdP2vvZoPMdlCIzOlIkPLgxE0IWueTXeBJhNs01pb8bLqmTIMlu4LvBELA/veiaj j5s8y542H/aHsfBf4MQUhHxO/BZV7h06KSUfIaY7OgAgKuGNB3UiaIUS5+a9gnEOQLDxKRy/ a7Q1v9S+Nvx+7j8iH3jkQJhxT6ZBhZGRx0gkH3T+F0nNDm5NaJUsaswgJrqFZkUGd2Mrm1qn KwXiAt8SIcENdq33R0KKKRC80Xgwj8Jn30vXLSG+NO1GH0UMcAxMwy/pvk6LU5JGjZR73J5U LVhH4MLbDggD3mPaiG8+fotTrJUPqqhg9hyUEPpYG7sqt74Xn79+CEZcjLHzyl6vAFE2W0kx lLtQtUZUHO36afFv8qGpO3ZqPvjBUuatXF6tvUQCwf3H6XMAEQEAAcLBXwQYAQoACQUCTmas +gIbDAAKCRAFLzZwGNXD2D/XD/0ddM/4ai1b+Tl1jznKajX3kG+MeEYeI4f40vco3rOLrnRG FOcbyyfVF69MKepie4OwoI1jcTU0ADecnbWnDNHpr0SczxBMro3bnrLhsmvjunTYIvssBZtB 4aVJjuLILPUlnhFqa7fbVq0ZQjbiV/rt2jBENdm9pbJZ6GjnpYIcAbPCCa/ffL4/SQRSYHXo hGiiS4y5jBTmK5ltfewLOw02fkexH+IJFrrGBXDSg6n2Sgxnn++NF34fXcm9piaw3mKsICm+ 0hdNh4afGZ6IWV8PG2teooVDp4dYih++xX/XS8zBCc1O9w4nzlP2gKzlqSWbhiWpifRJBFa4 WtAeJTdXYd37j/BI4RWWhnyw7aAPNGj33ytGHNUf6Ro2/jtj4tF1y/QFXqjJG/wGjpdtRfbt UjqLHIsvfPNNJq/958p74ndACidlWSHzj+Op26KpbFnmwNO0psiUsnhvHFwPO/vAbl3RsR5+ 0Ro+hvs2cEmQuv9r/bDlCfpzp2t3cK+rhxUqisOx8DZfz1BnkaoCRFbvvvk+7L/fomPntGPk qJciYE8TGHkZw1hOku+4OoM2GB5nEDlj+2TF/jLQ+EipX9PkPJYvxfRlC6dK8PKKfX9KdfmA IcgHfnV1jSn+8yH2djBPtKiqW0J69aIsyx7iV/03paPCjJh7Xq9vAzydN5U/UA== Organization: Canonical Message-ID: <99875b4f-7d46-a510-228b-f87960308477@canonical.com> Date: Thu, 21 Nov 2019 11:00:37 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191113181925.2437-17-casey@schaufler-ca.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 11/13/19 10:19 AM, Casey Schaufler wrote: > 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); > >