From patchwork Tue Mar 28 11:02:40 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 9648833 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A970660349 for ; Tue, 28 Mar 2017 11:04:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9DC61283FF for ; Tue, 28 Mar 2017 11:04:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 91DFE2026B; Tue, 28 Mar 2017 11:04:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 92E4E1FFAE for ; Tue, 28 Mar 2017 11:04:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932076AbdC1LDx (ORCPT ); Tue, 28 Mar 2017 07:03:53 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:61506 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755253AbdC1LDU (ORCPT ); Tue, 28 Mar 2017 07:03:20 -0400 Received: from fsav303.sakura.ne.jp (fsav303.sakura.ne.jp [153.120.85.134]) by www262.sakura.ne.jp (8.14.5/8.14.5) with ESMTP id v2SB2ioH093790; Tue, 28 Mar 2017 20:02:44 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav303.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav303.sakura.ne.jp); Tue, 28 Mar 2017 20:02:44 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav303.sakura.ne.jp) Received: from ccsecurity.localdomain (softbank126227147111.bbtec.net [126.227.147.111]) (authenticated bits=0) by www262.sakura.ne.jp (8.14.5/8.14.5) with ESMTP id v2SB2cYT093755 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Tue, 28 Mar 2017 20:02:43 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) From: Tetsuo Handa To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, Tetsuo Handa Subject: [PATCH] TOMOYO: Switch from per "struct cred" blob to per "struct task_struct" blob. Date: Tue, 28 Mar 2017 20:02:40 +0900 Message-Id: <1490698960-29861-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> X-Mailer: git-send-email 1.8.3.1 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Now that security_task_alloc() hook and "struct task_struct"->security field are revived, switch TOMOYO to use them because TOMOYO's security context is defined based on "struct task_struct" rather than "struct cred". By applying this patch, TOMOYO no longer uses "struct cred"->security which means that TOMOYO is ready for running with other fully armored LSM modules which use "struct cred"->security field. Signed-off-by: Tetsuo Handa --- security/tomoyo/common.h | 20 +++++-- security/tomoyo/domain.c | 8 ++- security/tomoyo/gc.c | 6 +-- security/tomoyo/securityfs_if.c | 22 ++++---- security/tomoyo/tomoyo.c | 112 +++++++++++++++++++--------------------- 5 files changed, 87 insertions(+), 81 deletions(-) diff --git a/security/tomoyo/common.h b/security/tomoyo/common.h index 361e7a2..5a7623b 100644 --- a/security/tomoyo/common.h +++ b/security/tomoyo/common.h @@ -684,7 +684,7 @@ struct tomoyo_domain_info { u8 group; /* Group number to use. */ bool is_deleted; /* Delete flag. */ bool flags[TOMOYO_MAX_DOMAIN_INFO_FLAGS]; - atomic_t users; /* Number of referring credentials. */ + atomic_t users; /* Number of referring "struct task_struct". */ }; /* @@ -911,6 +911,11 @@ struct tomoyo_policy_namespace { const char *name; }; +struct tomoyo_security { + struct tomoyo_domain_info *tomoyo_domain_info; + struct tomoyo_domain_info *saved_domain_info; /* Maybe NULL. */ +}; + /********** Function prototypes. **********/ bool tomoyo_address_matches_group(const bool is_ipv6, const __be32 *address, @@ -1202,7 +1207,16 @@ static inline void tomoyo_put_group(struct tomoyo_group *group) */ static inline struct tomoyo_domain_info *tomoyo_domain(void) { - return current_cred()->security; + struct tomoyo_security *ts = current->security; + + if (ts->saved_domain_info && !current->in_execve) { + struct tomoyo_domain_info *domain = ts->tomoyo_domain_info; + + ts->tomoyo_domain_info = ts->saved_domain_info; + ts->saved_domain_info = NULL; + atomic_dec(&domain->users); + } + return ts->tomoyo_domain_info; } /** @@ -1215,7 +1229,7 @@ static inline struct tomoyo_domain_info *tomoyo_domain(void) static inline struct tomoyo_domain_info *tomoyo_real_domain(struct task_struct *task) { - return task_cred_xxx(task, security); + return ((struct tomoyo_security *) task->security)->tomoyo_domain_info; } /** diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c index 00d223e..9f981d8 100644 --- a/security/tomoyo/domain.c +++ b/security/tomoyo/domain.c @@ -677,6 +677,7 @@ static int tomoyo_environ(struct tomoyo_execve *ee) */ int tomoyo_find_next_domain(struct linux_binprm *bprm) { + struct tomoyo_security *ts = current->security; struct tomoyo_domain_info *old_domain = tomoyo_domain(); struct tomoyo_domain_info *domain = NULL; const char *original_name = bprm->filename; @@ -841,8 +842,11 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm) if (!domain) domain = old_domain; /* Update reference count on "struct tomoyo_domain_info". */ - atomic_inc(&domain->users); - bprm->cred->security = domain; + if (domain != ts->tomoyo_domain_info) { + atomic_inc(&domain->users); + ts->saved_domain_info = ts->tomoyo_domain_info; + ts->tomoyo_domain_info = domain; + } kfree(exename.name); if (!retval) { ee->r.domain = domain; diff --git a/security/tomoyo/gc.c b/security/tomoyo/gc.c index 540bc29..75ae368 100644 --- a/security/tomoyo/gc.c +++ b/security/tomoyo/gc.c @@ -248,8 +248,8 @@ static inline void tomoyo_del_domain(struct list_head *element) struct tomoyo_acl_info *tmp; /* * Since this domain is referenced from neither - * "struct tomoyo_io_buffer" nor "struct cred"->security, we can delete - * elements without checking for is_deleted flag. + * "struct tomoyo_io_buffer" nor "struct tomoyo_security", + * we can delete elements without checking for is_deleted flag. */ list_for_each_entry_safe(acl, tmp, &domain->acl_info_list, list) { tomoyo_del_acl(&acl->list); @@ -433,7 +433,7 @@ static void tomoyo_try_to_gc(const enum tomoyo_policy_id type, break; case TOMOYO_ID_DOMAIN: /* - * Don't kfree() until all "struct cred"->security forget this + * Don't kfree() until all "struct tomoyo_security" forget this * element. */ if (atomic_read(&container_of diff --git a/security/tomoyo/securityfs_if.c b/security/tomoyo/securityfs_if.c index 06ab41b1..988261a 100644 --- a/security/tomoyo/securityfs_if.c +++ b/security/tomoyo/securityfs_if.c @@ -5,6 +5,7 @@ */ #include +#include /* security_module_enable() */ #include "common.h" /** @@ -66,18 +67,13 @@ static ssize_t tomoyo_write_self(struct file *file, const char __user *buf, if (!new_domain) { error = -ENOENT; } else { - struct cred *cred = prepare_creds(); - if (!cred) { - error = -ENOMEM; - } else { - struct tomoyo_domain_info *old_domain = - cred->security; - cred->security = new_domain; - atomic_inc(&new_domain->users); - atomic_dec(&old_domain->users); - commit_creds(cred); - error = 0; - } + struct tomoyo_domain_info *old_domain = + tomoyo_domain(); + ((struct tomoyo_security *) current->security) + ->tomoyo_domain_info = new_domain; + atomic_inc(&new_domain->users); + atomic_dec(&old_domain->users); + error = 0; } } tomoyo_read_unlock(idx); @@ -236,7 +232,7 @@ static int __init tomoyo_initerface_init(void) struct dentry *tomoyo_dir; /* Don't create securityfs entries unless registered. */ - if (current_cred()->security != &tomoyo_kernel_domain) + if (!security_module_enable("tomoyo")) return 0; tomoyo_dir = securityfs_create_dir("tomoyo", NULL); diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c index b5fb930..0de150d 100644 --- a/security/tomoyo/tomoyo.c +++ b/security/tomoyo/tomoyo.c @@ -8,59 +8,42 @@ #include "common.h" /** - * tomoyo_cred_alloc_blank - Target for security_cred_alloc_blank(). + * tomoyo_task_alloc - Target for security_task_alloc(). * - * @new: Pointer to "struct cred". - * @gfp: Memory allocation flags. + * @task: Pointer to "struct task_struct". + * @clone_flags: Not used. * - * Returns 0. - */ -static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp) -{ - new->security = NULL; - return 0; -} - -/** - * tomoyo_cred_prepare - Target for security_prepare_creds(). - * - * @new: Pointer to "struct cred". - * @old: Pointer to "struct cred". - * @gfp: Memory allocation flags. - * - * Returns 0. + * Returns 0 on success, negative value otherwise. */ -static int tomoyo_cred_prepare(struct cred *new, const struct cred *old, - gfp_t gfp) +static int tomoyo_task_alloc(struct task_struct *task, + unsigned long clone_flags) { - struct tomoyo_domain_info *domain = old->security; - new->security = domain; - if (domain) - atomic_inc(&domain->users); + struct tomoyo_security *ts = kzalloc(sizeof(*ts), GFP_KERNEL); + struct tomoyo_domain_info *domain = tomoyo_domain(); + + if (!ts) + return -ENOMEM; + ts->tomoyo_domain_info = domain; + atomic_inc(&domain->users); + task->security = ts; return 0; } /** - * tomoyo_cred_transfer - Target for security_transfer_creds(). + * tomoyo_task_free - Target for security_task_free(). * - * @new: Pointer to "struct cred". - * @old: Pointer to "struct cred". + * @task: Pointer to "struct task_struct". */ -static void tomoyo_cred_transfer(struct cred *new, const struct cred *old) +static void tomoyo_task_free(struct task_struct *task) { - tomoyo_cred_prepare(new, old, 0); -} + struct tomoyo_security *ts = task->security; + struct tomoyo_domain_info *domain = ts->tomoyo_domain_info; -/** - * tomoyo_cred_free - Target for security_cred_free(). - * - * @cred: Pointer to "struct cred". - */ -static void tomoyo_cred_free(struct cred *cred) -{ - struct tomoyo_domain_info *domain = cred->security; + atomic_dec(&domain->users); + domain = ts->saved_domain_info; if (domain) atomic_dec(&domain->users); + kfree(ts); } /** @@ -68,7 +51,7 @@ static void tomoyo_cred_free(struct cred *cred) * * @bprm: Pointer to "struct linux_binprm". * - * Returns 0 on success, negative value otherwise. + * Returns 0. */ static int tomoyo_bprm_set_creds(struct linux_binprm *bprm) { @@ -86,19 +69,8 @@ static int tomoyo_bprm_set_creds(struct linux_binprm *bprm) if (!tomoyo_policy_loaded) tomoyo_load_policy(bprm->filename); #endif - /* - * Release reference to "struct tomoyo_domain_info" stored inside - * "bprm->cred->security". New reference to "struct tomoyo_domain_info" - * stored inside "bprm->cred->security" will be acquired later inside - * tomoyo_find_next_domain(). - */ - atomic_dec(&((struct tomoyo_domain_info *) - bprm->cred->security)->users); - /* - * Tell tomoyo_bprm_check_security() is called for the first time of an - * execve operation. - */ - bprm->cred->security = NULL; + /* Restore and clear saved_domain_info if needed. */ + tomoyo_domain(); return 0; } @@ -111,7 +83,8 @@ static int tomoyo_bprm_set_creds(struct linux_binprm *bprm) */ static int tomoyo_bprm_check_security(struct linux_binprm *bprm) { - struct tomoyo_domain_info *domain = bprm->cred->security; + struct tomoyo_security *ts = current->security; + struct tomoyo_domain_info *domain = ts->saved_domain_info; /* * Execute permission is checked against pathname passed to do_execve() @@ -131,6 +104,24 @@ static int tomoyo_bprm_check_security(struct linux_binprm *bprm) } /** + * tomoyo_bprm_check_security - Target for security_bprm_check(). + * + * @bprm: Pointer to "struct linux_binprm". + */ +static void tomoyo_bprm_committed_creds(struct linux_binprm *bprm) +{ + struct tomoyo_security *ts = current->security; + struct tomoyo_domain_info *domain = ts->saved_domain_info; + + /* Clear saved_domain_info if needed. */ + if (domain) { + ts->saved_domain_info = NULL; + atomic_dec(&domain->users); + } +} + + +/** * tomoyo_inode_getattr - Target for security_inode_getattr(). * * @mnt: Pointer to "struct vfsmount". @@ -497,12 +488,11 @@ static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg, * registering TOMOYO. */ static struct security_hook_list tomoyo_hooks[] __lsm_ro_after_init = { - LSM_HOOK_INIT(cred_alloc_blank, tomoyo_cred_alloc_blank), - LSM_HOOK_INIT(cred_prepare, tomoyo_cred_prepare), - LSM_HOOK_INIT(cred_transfer, tomoyo_cred_transfer), - LSM_HOOK_INIT(cred_free, tomoyo_cred_free), + LSM_HOOK_INIT(task_alloc, tomoyo_task_alloc), + LSM_HOOK_INIT(task_free, tomoyo_task_free), LSM_HOOK_INIT(bprm_set_creds, tomoyo_bprm_set_creds), LSM_HOOK_INIT(bprm_check_security, tomoyo_bprm_check_security), + LSM_HOOK_INIT(bprm_committed_creds, tomoyo_bprm_committed_creds), LSM_HOOK_INIT(file_fcntl, tomoyo_file_fcntl), LSM_HOOK_INIT(file_open, tomoyo_file_open), LSM_HOOK_INIT(path_truncate, tomoyo_path_truncate), @@ -537,14 +527,16 @@ static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg, */ static int __init tomoyo_init(void) { - struct cred *cred = (struct cred *) current_cred(); + static struct tomoyo_security ts = { + .tomoyo_domain_info = &tomoyo_kernel_domain + }; if (!security_module_enable("tomoyo")) return 0; /* register ourselves with the security framework */ security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks), "tomoyo"); printk(KERN_INFO "TOMOYO Linux initialized\n"); - cred->security = &tomoyo_kernel_domain; + current->security = &ts; tomoyo_mm_init(); return 0; }