From patchwork Fri Nov 6 15:56:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11887353 X-Patchwork-Delegate: paul@paul-moore.com 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 27CF81130 for ; Fri, 6 Nov 2020 15:56:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 000F9208C7 for ; Fri, 6 Nov 2020 15:56:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="tUHYQlCo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727676AbgKFP4j (ORCPT ); Fri, 6 Nov 2020 10:56:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727229AbgKFP4h (ORCPT ); Fri, 6 Nov 2020 10:56:37 -0500 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D86BAC0613D4 for ; Fri, 6 Nov 2020 07:56:36 -0800 (PST) Received: by mail-qt1-x84a.google.com with SMTP id i20so1196862qtr.0 for ; Fri, 06 Nov 2020 07:56:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=bu5Eked262Yqjy7vLc/7v5hG2v0AiZ5jBwjzS/hxCOs=; b=tUHYQlCoc1s5aYJya18uS22d3UTuNreyZaKH6b0+Ng+PkQNmxnwx/JRRmeKT/1/OcR frWxCzVol+m7glkfQxEe73L334XNz/jIEy+tEgEZUXRq3RkFUIyCQu3x7Rr4CyiJ/wXO 9ySAck5isc2WeflM37CgZNunVBJ8j821EZYJ+kAgIeVVTRzZfU7+YbZjck9gyOOBW7nW WROEbsyT+zeadQHQRTJi7J66JE/EJCU32eUBVmtJ7PBQluRf9Y0/vshho6deYxMWhZko VN7pFN0kLzw9/HQKP08olKfvHXlzt5rZtGai+w7yJ2bKtseW3mYGE20jP55W/6ksA0VZ 9lbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=bu5Eked262Yqjy7vLc/7v5hG2v0AiZ5jBwjzS/hxCOs=; b=QfNJeRxCQAj+U8Ooll16j2K31tGxnOAuK9iVIz8lsMFxhHNg7nJWaxHAKq2SKPp57M a+SOaZSrO6rsgDNS9Xwwb36Ei6sa5QS/3E6Z8XiazEDULCfqfgavnuEajXO47hymHxs4 jmNzUcbrMRYKBQmtbGndpkqN0tmFdqC1/4BPVIQqJg19CxgzRF6Ve//uIZDlbZzGR4SB /lTto2TF23xduj5bQ9wdAHWrQ3CEi95+kIQ02hkYPqU6Evq/qRRqfC0G8xRBRd3JGyq4 Nv+m+QRr/k4pd2SzAeMn3zmv9RURusM0vBYxgLopk873+suGsVxPo3xlw872wh6SVQpR xyXw== X-Gm-Message-State: AOAM533jK3naqBsVn7rrm2LGlgAWLAQ0SuX3zQY5yKMYZGZITcC8FTln zH6/yLeKAmSD0omNiXCbW7c4b1Xx/4mC5aREeA== X-Google-Smtp-Source: ABdhPJx+CvqAWS4teVk5tHn3xTDEntP/bcjs0s4pTYnq0DlDWFNArmUzSNYmwEA+ClpRT/MWBvBIXsXRX4Fbm0AB8w== Sender: "lokeshgidra via sendgmr" X-Received: from lg.mtv.corp.google.com ([2620:15c:211:202:f693:9fff:fef4:29dd]) (user=lokeshgidra job=sendgmr) by 2002:a0c:e40c:: with SMTP id o12mr2222905qvl.29.1604678195875; Fri, 06 Nov 2020 07:56:35 -0800 (PST) Date: Fri, 6 Nov 2020 07:56:23 -0800 In-Reply-To: <20201106155626.3395468-1-lokeshgidra@google.com> Message-Id: <20201106155626.3395468-2-lokeshgidra@google.com> Mime-Version: 1.0 References: <20201106155626.3395468-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.29.1.341.ge80a0c044ae-goog Subject: [PATCH v12 1/4] security: add inode_init_security_anon() LSM hook From: Lokesh Gidra To: Andrea Arcangeli , Alexander Viro , James Morris , Stephen Smalley , Casey Schaufler , Eric Biggers Cc: "Serge E. Hallyn" , Paul Moore , Eric Paris , Lokesh Gidra , Daniel Colascione , Kees Cook , "Eric W. Biederman" , KP Singh , David Howells , Thomas Cedeno , Anders Roxell , Sami Tolvanen , Matthew Garrett , Aaron Goidel , Randy Dunlap , "Joel Fernandes (Google)" , YueHaibing , Christian Brauner , Alexei Starovoitov , Alexey Budankov , Adrian Reber , Aleksa Sarai , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, kaleshsingh@google.com, calin@google.com, surenb@google.com, nnk@google.com, jeffv@google.com, kernel-team@android.com, linux-mm@kvack.org, Andrew Morton , hch@infradead.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org This change adds a new LSM hook, inode_init_security_anon(), that will be used while creating secure anonymous inodes. The hook allows/denies its creation and assigns a security context to the inode. The new hook accepts an optional context_inode parameter that callers can use to provide additional contextual information to security modules for granting/denying permission to create an anon-inode of the same type. This context_inode's security_context can also be used to initialize the newly created anon-inode's security_context. Signed-off-by: Lokesh Gidra Reviewed-by: Eric Biggers --- include/linux/lsm_hook_defs.h | 2 ++ include/linux/lsm_hooks.h | 9 +++++++++ include/linux/security.h | 10 ++++++++++ security/security.c | 8 ++++++++ 4 files changed, 29 insertions(+) diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 32a940117e7a..435a2e22ff95 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -113,6 +113,8 @@ LSM_HOOK(void, LSM_RET_VOID, inode_free_security, struct inode *inode) LSM_HOOK(int, 0, inode_init_security, struct inode *inode, struct inode *dir, const struct qstr *qstr, const char **name, void **value, size_t *len) +LSM_HOOK(int, 0, inode_init_security_anon, struct inode *inode, + const struct qstr *name, const struct inode *context_inode) LSM_HOOK(int, 0, inode_create, struct inode *dir, struct dentry *dentry, umode_t mode) LSM_HOOK(int, 0, inode_link, struct dentry *old_dentry, struct inode *dir, diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index c503f7ab8afb..3af055b7ee1f 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -233,6 +233,15 @@ * Returns 0 if @name and @value have been successfully set, * -EOPNOTSUPP if no security attribute is needed, or * -ENOMEM on memory allocation failure. + * @inode_init_security_anon: + * Set up the incore security field for the new anonymous inode + * and return whether the inode creation is permitted by the security + * module or not. + * @inode contains the inode structure + * @name name of the anonymous inode class + * @context_inode optional related inode + * Returns 0 on success, -EACCES if the security module denies the + * creation of this inode, or another -errno upon other errors. * @inode_create: * Check permission to create a regular file. * @dir contains inode structure of the parent of the new file. diff --git a/include/linux/security.h b/include/linux/security.h index bc2725491560..7494a93b9ed9 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -323,6 +323,9 @@ void security_inode_free(struct inode *inode); int security_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, initxattrs initxattrs, void *fs_data); +int security_inode_init_security_anon(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode); int security_old_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, const char **name, void **value, size_t *len); @@ -737,6 +740,13 @@ static inline int security_inode_init_security(struct inode *inode, return 0; } +static inline int security_inode_init_security_anon(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode) +{ + return 0; +} + static inline int security_old_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, diff --git a/security/security.c b/security/security.c index a28045dc9e7f..8989ba6af4f6 100644 --- a/security/security.c +++ b/security/security.c @@ -1058,6 +1058,14 @@ int security_inode_init_security(struct inode *inode, struct inode *dir, } EXPORT_SYMBOL(security_inode_init_security); +int security_inode_init_security_anon(struct inode *inode, + const struct qstr *name, + const struct inode *context_inode) +{ + return call_int_hook(inode_init_security_anon, 0, inode, name, + context_inode); +} + int security_old_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, const char **name, void **value, size_t *len) From patchwork Fri Nov 6 15:56:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11887335 X-Patchwork-Delegate: paul@paul-moore.com 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 56D061752 for ; Fri, 6 Nov 2020 15:56:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F6F420728 for ; Fri, 6 Nov 2020 15:56:44 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Fri, 06 Nov 2020 07:56:39 -0800 (PST) Date: Fri, 6 Nov 2020 07:56:24 -0800 In-Reply-To: <20201106155626.3395468-1-lokeshgidra@google.com> Message-Id: <20201106155626.3395468-3-lokeshgidra@google.com> Mime-Version: 1.0 References: <20201106155626.3395468-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.29.1.341.ge80a0c044ae-goog Subject: [PATCH v12 2/4] fs: add LSM-supporting anon-inode interface From: Lokesh Gidra To: Andrea Arcangeli , Alexander Viro , James Morris , Stephen Smalley , Casey Schaufler , Eric Biggers Cc: "Serge E. Hallyn" , Paul Moore , Eric Paris , Lokesh Gidra , Daniel Colascione , Kees Cook , "Eric W. Biederman" , KP Singh , David Howells , Thomas Cedeno , Anders Roxell , Sami Tolvanen , Matthew Garrett , Aaron Goidel , Randy Dunlap , "Joel Fernandes (Google)" , YueHaibing , Christian Brauner , Alexei Starovoitov , Alexey Budankov , Adrian Reber , Aleksa Sarai , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, kaleshsingh@google.com, calin@google.com, surenb@google.com, nnk@google.com, jeffv@google.com, kernel-team@android.com, linux-mm@kvack.org, Andrew Morton , hch@infradead.org, Daniel Colascione Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org From: Daniel Colascione This change adds a new function, anon_inode_getfd_secure, that creates anonymous-node file with individual non-S_PRIVATE inode to which security modules can apply policy. Existing callers continue using the original singleton-inode kind of anonymous-inode file. We can transition anonymous inode users to the new kind of anonymous inode in individual patches for the sake of bisection and review. The new function accepts an optional context_inode parameter that callers can use to provide additional contextual information to security modules. For example, in case of userfaultfd, the created inode is a 'logical child' of the context_inode (userfaultfd inode of the parent process) in the sense that it provides the security context required during creation of the child process' userfaultfd inode. Signed-off-by: Daniel Colascione [Delete obsolete comments to alloc_anon_inode()] [Add context_inode description in comments to anon_inode_getfd_secure()] [Remove definition of anon_inode_getfile_secure() as there are no callers] [Make __anon_inode_getfile() static] [Use correct error cast in __anon_inode_getfile()] [Fix error handling in __anon_inode_getfile()] Signed-off-by: Lokesh Gidra Reviewed-by: Eric Biggers --- fs/anon_inodes.c | 150 ++++++++++++++++++++++++++---------- fs/libfs.c | 5 -- include/linux/anon_inodes.h | 5 ++ 3 files changed, 115 insertions(+), 45 deletions(-) diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index 89714308c25b..f4b35aaed7b2 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -55,61 +55,79 @@ static struct file_system_type anon_inode_fs_type = { .kill_sb = kill_anon_super, }; -/** - * anon_inode_getfile - creates a new file instance by hooking it up to an - * anonymous inode, and a dentry that describe the "class" - * of the file - * - * @name: [in] name of the "class" of the new file - * @fops: [in] file operations for the new file - * @priv: [in] private data for the new file (will be file's private_data) - * @flags: [in] flags - * - * Creates a new file by hooking it on a single inode. This is useful for files - * that do not need to have a full-fledged inode in order to operate correctly. - * All the files created with anon_inode_getfile() will share a single inode, - * hence saving memory and avoiding code duplication for the file/inode/dentry - * setup. Returns the newly created file* or an error pointer. - */ -struct file *anon_inode_getfile(const char *name, - const struct file_operations *fops, - void *priv, int flags) +static struct inode *anon_inode_make_secure_inode( + const char *name, + const struct inode *context_inode) { - struct file *file; + struct inode *inode; + const struct qstr qname = QSTR_INIT(name, strlen(name)); + int error; + + inode = alloc_anon_inode(anon_inode_mnt->mnt_sb); + if (IS_ERR(inode)) + return inode; + inode->i_flags &= ~S_PRIVATE; + error = security_inode_init_security_anon(inode, &qname, context_inode); + if (error) { + iput(inode); + return ERR_PTR(error); + } + return inode; +} - if (IS_ERR(anon_inode_inode)) - return ERR_PTR(-ENODEV); +static struct file *__anon_inode_getfile(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode, + bool secure) +{ + struct inode *inode; + struct file *file; if (fops->owner && !try_module_get(fops->owner)) return ERR_PTR(-ENOENT); - /* - * We know the anon_inode inode count is always greater than zero, - * so ihold() is safe. - */ - ihold(anon_inode_inode); - file = alloc_file_pseudo(anon_inode_inode, anon_inode_mnt, name, + if (secure) { + inode = anon_inode_make_secure_inode(name, context_inode); + if (IS_ERR(inode)) { + file = ERR_CAST(inode); + goto err; + } + } else { + inode = anon_inode_inode; + if (IS_ERR(inode)) { + file = ERR_PTR(-ENODEV); + goto err; + } + /* + * We know the anon_inode inode count is always + * greater than zero, so ihold() is safe. + */ + ihold(inode); + } + + file = alloc_file_pseudo(inode, anon_inode_mnt, name, flags & (O_ACCMODE | O_NONBLOCK), fops); if (IS_ERR(file)) - goto err; + goto err_iput; - file->f_mapping = anon_inode_inode->i_mapping; + file->f_mapping = inode->i_mapping; file->private_data = priv; return file; +err_iput: + iput(inode); err: - iput(anon_inode_inode); module_put(fops->owner); return file; } -EXPORT_SYMBOL_GPL(anon_inode_getfile); /** - * anon_inode_getfd - creates a new file instance by hooking it up to an - * anonymous inode, and a dentry that describe the "class" - * of the file + * anon_inode_getfile - creates a new file instance by hooking it up to an + * anonymous inode, and a dentry that describe the "class" + * of the file * * @name: [in] name of the "class" of the new file * @fops: [in] file operations for the new file @@ -118,12 +136,23 @@ EXPORT_SYMBOL_GPL(anon_inode_getfile); * * Creates a new file by hooking it on a single inode. This is useful for files * that do not need to have a full-fledged inode in order to operate correctly. - * All the files created with anon_inode_getfd() will share a single inode, + * All the files created with anon_inode_getfile() will share a single inode, * hence saving memory and avoiding code duplication for the file/inode/dentry - * setup. Returns new descriptor or an error code. + * setup. Returns the newly created file* or an error pointer. */ -int anon_inode_getfd(const char *name, const struct file_operations *fops, - void *priv, int flags) +struct file *anon_inode_getfile(const char *name, + const struct file_operations *fops, + void *priv, int flags) +{ + return __anon_inode_getfile(name, fops, priv, flags, NULL, false); +} +EXPORT_SYMBOL_GPL(anon_inode_getfile); + +static int __anon_inode_getfd(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode, + bool secure) { int error, fd; struct file *file; @@ -133,7 +162,8 @@ int anon_inode_getfd(const char *name, const struct file_operations *fops, return error; fd = error; - file = anon_inode_getfile(name, fops, priv, flags); + file = __anon_inode_getfile(name, fops, priv, flags, context_inode, + secure); if (IS_ERR(file)) { error = PTR_ERR(file); goto err_put_unused_fd; @@ -146,8 +176,48 @@ int anon_inode_getfd(const char *name, const struct file_operations *fops, put_unused_fd(fd); return error; } + +/** + * anon_inode_getfd - creates a new file instance by hooking it up to + * an anonymous inode and a dentry that describe + * the "class" of the file + * + * @name: [in] name of the "class" of the new file + * @fops: [in] file operations for the new file + * @priv: [in] private data for the new file (will be file's private_data) + * @flags: [in] flags + * + * Creates a new file by hooking it on a single inode. This is + * useful for files that do not need to have a full-fledged inode in + * order to operate correctly. All the files created with + * anon_inode_getfd() will use the same singleton inode, reducing + * memory use and avoiding code duplication for the file/inode/dentry + * setup. Returns a newly created file descriptor or an error code. + */ +int anon_inode_getfd(const char *name, const struct file_operations *fops, + void *priv, int flags) +{ + return __anon_inode_getfd(name, fops, priv, flags, NULL, false); +} EXPORT_SYMBOL_GPL(anon_inode_getfd); +/** + * Like anon_inode_getfd(), but creates a new !S_PRIVATE anon inode rather than + * reuse the singleton anon inode, and call the anon_init_security_anon() LSM + * hook. This allows the inode to have its own security context and for a LSM + * to reject creation of the inode. An optional @context_inode argument is + * also added to provide the logical relationship with the new inode. The LSM + * may use @context_inode in inode_init_security_anon(), but a reference to it + * is not held. + */ +int anon_inode_getfd_secure(const char *name, const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode) +{ + return __anon_inode_getfd(name, fops, priv, flags, context_inode, true); +} +EXPORT_SYMBOL_GPL(anon_inode_getfd_secure); + static int __init anon_inode_init(void) { anon_inode_mnt = kern_mount(&anon_inode_fs_type); diff --git a/fs/libfs.c b/fs/libfs.c index fc34361c1489..51c19c72e563 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1212,11 +1212,6 @@ static int anon_set_page_dirty(struct page *page) return 0; }; -/* - * A single inode exists for all anon_inode files. Contrary to pipes, - * anon_inode inodes have no associated per-instance data, so we need - * only allocate one of them. - */ struct inode *alloc_anon_inode(struct super_block *s) { static const struct address_space_operations anon_aops = { diff --git a/include/linux/anon_inodes.h b/include/linux/anon_inodes.h index d0d7d96261ad..71881a2b6f78 100644 --- a/include/linux/anon_inodes.h +++ b/include/linux/anon_inodes.h @@ -10,12 +10,17 @@ #define _LINUX_ANON_INODES_H struct file_operations; +struct inode; struct file *anon_inode_getfile(const char *name, const struct file_operations *fops, void *priv, int flags); int anon_inode_getfd(const char *name, const struct file_operations *fops, void *priv, int flags); +int anon_inode_getfd_secure(const char *name, + const struct file_operations *fops, + void *priv, int flags, + const struct inode *context_inode); #endif /* _LINUX_ANON_INODES_H */ From patchwork Fri Nov 6 15:56:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11887339 X-Patchwork-Delegate: paul@paul-moore.com 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 786C71744 for ; Fri, 6 Nov 2020 15:56:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 40D29208C7 for ; Fri, 6 Nov 2020 15:56:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ffl1DjsL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727737AbgKFP4q (ORCPT ); Fri, 6 Nov 2020 10:56:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57474 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727721AbgKFP4o (ORCPT ); Fri, 6 Nov 2020 10:56:44 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D24A6C0613D4 for ; Fri, 6 Nov 2020 07:56:43 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id y11so2096476ybm.22 for ; Fri, 06 Nov 2020 07:56:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=L4KGFFWDHlU66vPQG585OdMG0AUk6bVr7qLzNQZAqk0=; b=ffl1DjsLtbx4Na6zWHq8zJ/fNOh3xFnqff+6leag11fesgjIHAPz7OMbIQHlSJDtsL vp1Hf866chPTwdiGFaezEgU/0zK/96RUqzjiFUGhXJAbltgNqmkuWbzq4GptwFEzYzZ0 +FHYk/rzrzQwtMx7FF3/5ctZf3gaa/xTSZKilLw6U7drImewFIUOwm5TI3Izl2dov6Ps S8xJ2FZDBpOefQEjDSUiTusb1rqoqHzmhLRdw9JRBHUKW+h2Go7C2NJHLRyM44RROrnI u2RiDTPBrn66PObViiWK3uwTe0MSK6s2ZbX10/FnIpl8VFQVEMJjpV5f4yQBAIAvoM5c s5xQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=L4KGFFWDHlU66vPQG585OdMG0AUk6bVr7qLzNQZAqk0=; b=XMUinmx1dIP0TUnIXF9zWwun91H23cTMEaX0jLamlh2q2frXIpvMcI3wHfHYRxkTiD twaUC52c/BQ/u245LnC0c41G3vyD/6Y7zFkOroScYBQm7h3oX2RRVEdvGtkrY6UtH6bE 6cRq0itM34xqIQZTODnhwvkLCim2UMxyHwi5dfw9eo36D5Ul3EqGZ3MPi6ZosCk9+sAD X40L1yUJfcHC3WWE8sOlJQoCJcWcUTs3syUScVsTTNfwY/Q4DUYcujEKDI8XmIkBOF/n vDosidTRtXnPMlRAzMRx/cnFxJGxtkg65m1LgRz1wuaM7VYLR/GCeLPPzWDyv5mXuWbN Ak7w== X-Gm-Message-State: AOAM530IOFzYB21FgmnEKwy9wXmiGFDVOWAVUUFhHzZ/mhEcBAqiuQYx gdVk1nh+XYC+SLc1klh0aRMJIEeHRwXmo/Lcow== X-Google-Smtp-Source: ABdhPJyfDOocb7mOy/FefZ5Q9p5psuC3ih70I08ET9g06WqySi1lWVaasXmP4ckhtBQ08WiLsg2lyvOog2OeNS5ykA== Sender: "lokeshgidra via sendgmr" X-Received: from lg.mtv.corp.google.com ([2620:15c:211:202:f693:9fff:fef4:29dd]) (user=lokeshgidra job=sendgmr) by 2002:a25:60d7:: with SMTP id u206mr3591699ybb.315.1604678202914; Fri, 06 Nov 2020 07:56:42 -0800 (PST) Date: Fri, 6 Nov 2020 07:56:25 -0800 In-Reply-To: <20201106155626.3395468-1-lokeshgidra@google.com> Message-Id: <20201106155626.3395468-4-lokeshgidra@google.com> Mime-Version: 1.0 References: <20201106155626.3395468-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.29.1.341.ge80a0c044ae-goog Subject: [PATCH v12 3/4] selinux: teach SELinux about anonymous inodes From: Lokesh Gidra To: Andrea Arcangeli , Alexander Viro , James Morris , Stephen Smalley , Casey Schaufler , Eric Biggers Cc: "Serge E. Hallyn" , Paul Moore , Eric Paris , Lokesh Gidra , Daniel Colascione , Kees Cook , "Eric W. Biederman" , KP Singh , David Howells , Thomas Cedeno , Anders Roxell , Sami Tolvanen , Matthew Garrett , Aaron Goidel , Randy Dunlap , "Joel Fernandes (Google)" , YueHaibing , Christian Brauner , Alexei Starovoitov , Alexey Budankov , Adrian Reber , Aleksa Sarai , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, kaleshsingh@google.com, calin@google.com, surenb@google.com, nnk@google.com, jeffv@google.com, kernel-team@android.com, linux-mm@kvack.org, Andrew Morton , hch@infradead.org, Daniel Colascione Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org From: Daniel Colascione This change uses the anon_inodes and LSM infrastructure introduced in the previous patches to give SELinux the ability to control anonymous-inode files that are created using the new anon_inode_getfd_secure() function. 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 Signed-off-by: Lokesh Gidra --- 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 6b1826fc3658..1c0adcdce7a8 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2927,6 +2927,58 @@ 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_initialized(&selinux_state))) + 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); @@ -6992,6 +7044,7 @@ 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 40cebde62856..ba2e01a6955c 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -249,6 +249,8 @@ struct security_class_mapping secclass_map[] = { {"open", "cpu", "kernel", "tracepoint", "read", "write"} }, { "lockdown", { "integrity", "confidentiality", NULL } }, + { "anon_inode", + { COMMON_FILE_PERMS, NULL } }, { NULL } }; From patchwork Fri Nov 6 15:56:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11887351 X-Patchwork-Delegate: paul@paul-moore.com 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 2F0E31130 for ; Fri, 6 Nov 2020 15:56:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 084A02224B for ; Fri, 6 Nov 2020 15:56:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RsQT+l1C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727765AbgKFP4y (ORCPT ); Fri, 6 Nov 2020 10:56:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727665AbgKFP4x (ORCPT ); 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h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=WDkvhhk+gB3QxGd+Be5zd3cestt1bSfFZfMdeZMOFkc=; b=IO6FHfi8eX9lpWMffZhyWT9pEkahcl96ZcEM+3tQ01qE99jV8kebQm4QvPX/pmJvva 2zdjK8IRZExuTFrJEKt+albzXjN2inlACML7Dxy38Rz0jzO99kpQoUsUJ7jKqfhb7FTB mX7Jr6Em670TNFj2Z+sR4aIxFzrKcIjs9gjMfOc1Z3wmTBJL7VRSzYndw7OBKmNp21j7 ZK3k5a2XnxzKEcpZlKjHi2A7d1DNw3kkN2zkYkJcQ4bJErmFDrADkxxpR6XaNeBxCtb0 ggKIOx9FN91LbqF/DUK7QObwhlFdzqJRBhWNk2A6RH/aUUJr8oTj/9IZkV+j4iHMxVaW /Iow== X-Gm-Message-State: AOAM5316oOAq048yjjjk3eGCLkLfIUz2POImeAy4a2rOE3t/N8pGbkIS sI5Do1Uc8P8K9I+yLBcyAT7kQKtSjxVEbBzi6w== X-Google-Smtp-Source: ABdhPJyr6d4kWf9xCCa5Q5B2Li129pMxIihfl7MrB7NAAAhzq/yphrSlonTBTACs7Hm/3feKqNqDhVnqI0/i8x7rGQ== Sender: "lokeshgidra via sendgmr" X-Received: from lg.mtv.corp.google.com ([2620:15c:211:202:f693:9fff:fef4:29dd]) (user=lokeshgidra job=sendgmr) by 2002:a17:902:ee85:b029:d6:c43e:2321 with SMTP id a5-20020a170902ee85b02900d6c43e2321mr2200868pld.29.1604678211192; Fri, 06 Nov 2020 07:56:51 -0800 (PST) Date: Fri, 6 Nov 2020 07:56:26 -0800 In-Reply-To: <20201106155626.3395468-1-lokeshgidra@google.com> Message-Id: <20201106155626.3395468-5-lokeshgidra@google.com> Mime-Version: 1.0 References: <20201106155626.3395468-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.29.1.341.ge80a0c044ae-goog Subject: [PATCH v12 4/4] userfaultfd: use secure anon inodes for userfaultfd From: Lokesh Gidra To: Andrea Arcangeli , Alexander Viro , James Morris , Stephen Smalley , Casey Schaufler , Eric Biggers Cc: "Serge E. Hallyn" , Paul Moore , Eric Paris , Lokesh Gidra , Daniel Colascione , Kees Cook , "Eric W. Biederman" , KP Singh , David Howells , Thomas Cedeno , Anders Roxell , Sami Tolvanen , Matthew Garrett , Aaron Goidel , Randy Dunlap , "Joel Fernandes (Google)" , YueHaibing , Christian Brauner , Alexei Starovoitov , Alexey Budankov , Adrian Reber , Aleksa Sarai , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, kaleshsingh@google.com, calin@google.com, surenb@google.com, nnk@google.com, jeffv@google.com, kernel-team@android.com, linux-mm@kvack.org, Andrew Morton , hch@infradead.org, Daniel Colascione , Eric Biggers Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org From: Daniel Colascione This change gives userfaultfd file descriptors a real security context, allowing policy to act on them. Signed-off-by: Daniel Colascione [Remove owner inode from userfaultfd_ctx] [Use anon_inode_getfd_secure() instead of anon_inode_getfile_secure() in userfaultfd syscall] [Use inode of file in userfaultfd_read() in resolve_userfault_fork()] Signed-off-by: Lokesh Gidra Reviewed-by: Eric Biggers --- fs/userfaultfd.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 000b457ad087..dd78daf06de6 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -972,14 +972,14 @@ static __poll_t userfaultfd_poll(struct file *file, poll_table *wait) static const struct file_operations userfaultfd_fops; -static int resolve_userfault_fork(struct userfaultfd_ctx *ctx, - struct userfaultfd_ctx *new, +static int resolve_userfault_fork(struct userfaultfd_ctx *new, + struct inode *inode, struct uffd_msg *msg) { int fd; - fd = anon_inode_getfd("[userfaultfd]", &userfaultfd_fops, new, - O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS)); + fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, new, + O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS), inode); if (fd < 0) return fd; @@ -989,7 +989,7 @@ static int resolve_userfault_fork(struct userfaultfd_ctx *ctx, } static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait, - struct uffd_msg *msg) + struct uffd_msg *msg, struct inode *inode) { ssize_t ret; DECLARE_WAITQUEUE(wait, current); @@ -1100,7 +1100,7 @@ static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait, spin_unlock_irq(&ctx->fd_wqh.lock); if (!ret && msg->event == UFFD_EVENT_FORK) { - ret = resolve_userfault_fork(ctx, fork_nctx, msg); + ret = resolve_userfault_fork(fork_nctx, inode, msg); spin_lock_irq(&ctx->event_wqh.lock); if (!list_empty(&fork_event)) { /* @@ -1160,6 +1160,7 @@ static ssize_t userfaultfd_read(struct file *file, char __user *buf, ssize_t _ret, ret = 0; struct uffd_msg msg; int no_wait = file->f_flags & O_NONBLOCK; + struct inode *inode = file_inode(file); if (ctx->state == UFFD_STATE_WAIT_API) return -EINVAL; @@ -1167,7 +1168,7 @@ static ssize_t userfaultfd_read(struct file *file, char __user *buf, for (;;) { if (count < sizeof(msg)) return ret ? ret : -EINVAL; - _ret = userfaultfd_ctx_read(ctx, no_wait, &msg); + _ret = userfaultfd_ctx_read(ctx, no_wait, &msg, inode); if (_ret < 0) return ret ? ret : _ret; if (copy_to_user((__u64 __user *) buf, &msg, sizeof(msg))) @@ -1985,8 +1986,8 @@ SYSCALL_DEFINE1(userfaultfd, int, flags) /* prevent the mm struct to be freed */ mmgrab(ctx->mm); - fd = anon_inode_getfd("[userfaultfd]", &userfaultfd_fops, ctx, - O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS)); + fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, ctx, + O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL); if (fd < 0) { mmdrop(ctx->mm); kmem_cache_free(userfaultfd_ctx_cachep, ctx);