From: Daniel Colascione <dancol@google.com> To: timmurray@google.com, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, viro@zeniv.linux.org.uk, paul@paul-moore.com, nnk@google.com, sds@tycho.nsa.gov, lokeshgidra@google.com, jmorris@namei.org Cc: Daniel Colascione <dancol@google.com> Subject: [PATCH v4 2/3] Teach SELinux about anonymous inodes Date: Thu, 26 Mar 2020 13:06:33 -0700 Message-ID: <20200326200634.222009-3-dancol@google.com> (raw) In-Reply-To: <20200326200634.222009-1-dancol@google.com> This change uses the anon_inodes and LSM infrastructure introduced in the previous patch to give SELinux the ability to control anonymous-inode files that are created using the new _secure() anon_inodes functions. A SELinux policy author detects and controls these anonymous inodes by adding a name-based type_transition rule that assigns a new security type to anonymous-inode files created in some domain. The name used for the name-based transition is the name associated with the anonymous inode for file listings --- e.g., "[userfaultfd]" or "[perf_event]". Example: type uffd_t; type_transition sysadm_t sysadm_t : anon_inode uffd_t "[userfaultfd]"; allow sysadm_t uffd_t:anon_inode { create }; (The next patch in this series is necessary for making userfaultfd support this new interface. The example above is just for exposition.) Signed-off-by: Daniel Colascione <dancol@google.com> --- security/selinux/hooks.c | 53 +++++++++++++++++++++++++++++ security/selinux/include/classmap.h | 2 ++ 2 files changed, 55 insertions(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 1659b59fb5d7..6f7222d2e404 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2915,6 +2915,58 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir, return 0; } +static int selinux_inode_init_security_anon(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode) +{ + const struct task_security_struct *tsec = selinux_cred(current_cred()); + struct common_audit_data ad; + struct inode_security_struct *isec; + int rc; + + if (unlikely(!selinux_state.initialized)) + return 0; + + isec = selinux_inode(inode); + + /* + * We only get here once per ephemeral inode. The inode has + * been initialized via inode_alloc_security but is otherwise + * untouched. + */ + + if (context_inode) { + struct inode_security_struct *context_isec = + selinux_inode(context_inode); + isec->sclass = context_isec->sclass; + isec->sid = context_isec->sid; + } else { + isec->sclass = SECCLASS_ANON_INODE; + rc = security_transition_sid( + &selinux_state, tsec->sid, tsec->sid, + isec->sclass, name, &isec->sid); + if (rc) + return rc; + } + + isec->initialized = LABEL_INITIALIZED; + + /* + * Now that we've initialized security, check whether we're + * allowed to actually create this type of anonymous inode. + */ + + ad.type = LSM_AUDIT_DATA_INODE; + ad.u.inode = inode; + + return avc_has_perm(&selinux_state, + tsec->sid, + isec->sid, + isec->sclass, + FILE__CREATE, + &ad); +} + static int selinux_inode_create(struct inode *dir, struct dentry *dentry, umode_t mode) { return may_create(dir, dentry, SECCLASS_FILE); @@ -6923,6 +6975,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(inode_free_security, selinux_inode_free_security), LSM_HOOK_INIT(inode_init_security, selinux_inode_init_security), + LSM_HOOK_INIT(inode_init_security_anon, selinux_inode_init_security_anon), LSM_HOOK_INIT(inode_create, selinux_inode_create), LSM_HOOK_INIT(inode_link, selinux_inode_link), LSM_HOOK_INIT(inode_unlink, selinux_inode_unlink), diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index 986f3ac14282..263750b6aaac 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -248,6 +248,8 @@ struct security_class_mapping secclass_map[] = { {"open", "cpu", "kernel", "tracepoint", "read", "write"} }, { "lockdown", { "integrity", "confidentiality", NULL } }, + { "anon_inode", + { COMMON_FILE_PERMS, NULL } }, { NULL } }; -- 2.25.1.696.g5e7596f4ac-goog
next prev parent reply index Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-11 22:55 [PATCH v2 0/6] Harden userfaultfd Daniel Colascione 2020-02-11 22:55 ` [PATCH v2 1/6] Add a new flags-accepting interface for anonymous inodes Daniel Colascione 2020-02-12 16:37 ` Stephen Smalley 2020-02-12 17:23 ` Daniel Colascione 2020-02-11 22:55 ` [PATCH v2 2/6] Add a concept of a "secure" anonymous file Daniel Colascione 2020-02-12 16:49 ` Stephen Smalley 2020-02-14 22:13 ` kbuild test robot 2020-02-11 22:55 ` [PATCH v2 3/6] Teach SELinux about a new userfaultfd class Daniel Colascione 2020-02-12 17:05 ` Stephen Smalley 2020-02-12 17:19 ` Daniel Colascione 2020-02-12 18:04 ` Stephen Smalley 2020-02-12 18:59 ` Stephen Smalley 2020-02-12 19:04 ` Daniel Colascione 2020-02-12 19:11 ` Stephen Smalley 2020-02-12 19:13 ` Daniel Colascione 2020-02-12 19:17 ` Stephen Smalley 2020-02-11 22:55 ` [PATCH v2 4/6] Wire UFFD up to SELinux Daniel Colascione 2020-02-11 22:55 ` [PATCH v2 5/6] Let userfaultfd opt out of handling kernel-mode faults Daniel Colascione 2020-02-11 22:55 ` [PATCH v2 6/6] Add a new sysctl for limiting userfaultfd to user mode faults Daniel Colascione 2020-02-11 23:13 ` [PATCH v2 0/6] Harden userfaultfd Casey Schaufler 2020-02-11 23:27 ` Daniel Colascione 2020-02-12 16:09 ` Stephen Smalley 2020-02-21 17:56 ` James Morris 2020-02-12 7:50 ` Kees Cook 2020-02-12 16:54 ` Jann Horn 2020-02-12 17:14 ` Peter Xu 2020-02-12 19:41 ` Andrea Arcangeli 2020-02-12 20:04 ` Daniel Colascione 2020-02-12 23:41 ` Andrea Arcangeli 2020-02-12 17:12 ` Daniel Colascione 2020-02-14 3:26 ` [PATCH 0/3] SELinux support for anonymous inodes and UFFD Daniel Colascione 2020-02-14 3:26 ` [PATCH 1/3] Add a new LSM-supporting anonymous inode interface Daniel Colascione 2020-02-14 3:26 ` [PATCH 2/3] Teach SELinux about anonymous inodes Daniel Colascione 2020-02-14 16:39 ` Stephen Smalley 2020-02-14 17:21 ` Daniel Colascione 2020-02-14 18:02 ` Stephen Smalley 2020-02-14 18:08 ` Stephen Smalley 2020-02-14 20:24 ` Stephen Smalley 2020-02-14 3:26 ` [PATCH 3/3] Wire UFFD up to SELinux Daniel Colascione 2020-03-25 23:02 ` [PATCH v2 0/3] SELinux support for anonymous inodes and UFFD Daniel Colascione 2020-03-25 23:02 ` [PATCH v2 1/3] Add a new LSM-supporting anonymous inode interface Daniel Colascione 2020-03-26 13:53 ` Stephen Smalley 2020-03-25 23:02 ` [PATCH v2 2/3] Teach SELinux about anonymous inodes Daniel Colascione 2020-03-26 13:58 ` Stephen Smalley 2020-03-26 17:59 ` Daniel Colascione 2020-03-26 17:37 ` Stephen Smalley 2020-03-25 23:02 ` [PATCH v2 3/3] Wire UFFD up to SELinux Daniel Colascione 2020-03-25 23:49 ` Casey Schaufler 2020-03-26 18:14 ` [PATCH v3 0/3] SELinux support for anonymous inodes and UFFD Daniel Colascione 2020-03-26 18:14 ` [PATCH v3 1/3] Add a new LSM-supporting anonymous inode interface Daniel Colascione 2020-03-26 19:00 ` Stephen Smalley 2020-03-26 18:14 ` [PATCH v3 2/3] Teach SELinux about anonymous inodes Daniel Colascione 2020-03-26 19:02 ` Stephen Smalley 2020-03-26 18:14 ` [PATCH v3 3/3] Wire UFFD up to SELinux Daniel Colascione 2020-03-26 20:06 ` [PATCH v4 0/3] SELinux support for anonymous inodes and UFFD Daniel Colascione 2020-03-26 20:06 ` [PATCH v4 1/3] Add a new LSM-supporting anonymous inode interface Daniel Colascione 2020-03-27 13:40 ` Stephen Smalley 2020-03-26 20:06 ` Daniel Colascione [this message] 2020-03-27 13:41 ` [PATCH v4 2/3] Teach SELinux about anonymous inodes Stephen Smalley 2020-03-26 20:06 ` [PATCH v4 3/3] Wire UFFD up to SELinux Daniel Colascione 2020-04-01 21:39 ` [PATCH v5 0/3] SELinux support for anonymous inodes and UFFD Daniel Colascione 2020-04-01 21:39 ` [PATCH v5 1/3] Add a new LSM-supporting anonymous inode interface Daniel Colascione 2020-05-07 16:02 ` James Morris 2020-08-04 21:22 ` Eric Biggers 2020-04-01 21:39 ` [PATCH v5 2/3] Teach SELinux about anonymous inodes Daniel Colascione 2020-04-01 21:39 ` [PATCH v5 3/3] Wire UFFD up to SELinux Daniel Colascione 2020-08-04 21:16 ` Eric Biggers 2020-04-13 13:29 ` [PATCH v5 0/3] SELinux support for anonymous inodes and UFFD Daniel Colascione 2020-04-22 16:55 ` James Morris 2020-04-22 17:12 ` Casey Schaufler 2020-04-23 22:24 ` Casey Schaufler 2020-04-27 16:18 ` Casey Schaufler 2020-04-27 16:48 ` Stephen Smalley 2020-04-27 17:12 ` Casey Schaufler 2020-04-29 17:02 ` Stephen Smalley 2020-04-27 17:15 ` Casey Schaufler 2020-04-27 19:40 ` Stephen Smalley 2020-06-04 3:56 ` James Morris 2020-06-04 18:51 ` Stephen Smalley 2020-06-04 19:24 ` Lokesh Gidra
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