From patchwork Mon Sep 11 19:50:22 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Salvatore Mesoraca X-Patchwork-Id: 9948009 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 87C6A602C9 for ; Mon, 11 Sep 2017 19:53:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7E36828D0C for ; Mon, 11 Sep 2017 19:53:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 72FD628D32; Mon, 11 Sep 2017 19:53:03 +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=-2.1 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, GAPPY_SUBJECT, RCVD_IN_DNSWL_MED, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 85E3B28D0C for ; Mon, 11 Sep 2017 19:53:00 +0000 (UTC) Received: (qmail 1910 invoked by uid 550); 11 Sep 2017 19:51:56 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 1811 invoked from network); 11 Sep 2017 19:51:54 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=WKT/gIuTDhVsDIICu53YNf+0Ja+FcVsQY4rzwzzhJd4=; b=h/d37Ec3X1EbN/meare17wSt1dJCBruI01SPUqaONm9RI0StQY4eTrio4t/6NbR3lK wadKCLzB4U+pasERsWKU92TIy4443MnK3CeuL7jfj/Lttt/5FMzDVZhfzf73lbNKxpRW pTpQ5h1qQQCWXs9gIwCoVxuuGq/06vMwYX7R5Or87MD+wYSYusqpNwmKNfr0XfvzwPHR KNGYdxO4YiEu1zi00CkXxBymzqIXfBjeRGtUcvqkcLejzynETwy1VWrWHEPgwXOakgvU XS3ic9mp4Sxjk7DDKPnJrXmEzq2uszXKe05i/9D5Ofs5x1U4jIWsuNeU7XpqAUrz8W5v hYfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=WKT/gIuTDhVsDIICu53YNf+0Ja+FcVsQY4rzwzzhJd4=; b=spEWR4k7EIGMXri+txMXdeWSH6QOPHb6v5r+uP0ygcw1okVVf8UBlvdl3OcKMdFh22 NiUAiBr4VUWSzfRAM9rlM6WcGBqAk9P+Lp+V2rHGBw2jKPfsY7mXtbchnIEV39n0YIBm f9jSH1QvZC92gaGgKo+IxdOAhGJEyZlx9luigw5XVKtjmsR68oq7xMy1FBH6LIhzNw6j UvNv1XUxxF4IFC4+GnM+i0kpxG27opKnhtyNZoq0cdjTrT04Xu49YhyRKkePEWZI4y1L 2zADn1ZWj08aSRbKyD/IEObAvUQMCu/J5Bk1sqRST2eBPdHZWTQysQhjuuqhw0WPXbV8 9TdA== X-Gm-Message-State: AHPjjUjMQnpEJxJyiQDMoNNTsRk5UW+695OzEYTd2/rKGaCH6/p+JLyw uBUOWO4hc0WCXejqeIyqmnU= X-Google-Smtp-Source: AOwi7QA8GSApwL8LfKzAz1CL2JVcFwhu5+FNOQi4n3EpqD2ECWDuR8czNc9M/CbKuM2I5QpvwzFl0g== X-Received: by 10.28.70.133 with SMTP id t127mr947280wma.42.1505159502843; Mon, 11 Sep 2017 12:51:42 -0700 (PDT) From: Salvatore Mesoraca To: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org, kernel-hardening@lists.openwall.com, Salvatore Mesoraca , Brad Spengler , PaX Team , Casey Schaufler , Kees Cook , James Morris , "Serge E. Hallyn" Date: Mon, 11 Sep 2017 21:50:22 +0200 Message-Id: <1505159427-11747-5-git-send-email-s.mesoraca16@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1505159427-11747-1-git-send-email-s.mesoraca16@gmail.com> References: <1505159427-11747-1-git-send-email-s.mesoraca16@gmail.com> Subject: [kernel-hardening] [RFC v3 4/9] S.A.R.A. cred blob management X-Virus-Scanned: ClamAV using ClamSMTP Creation of the S.A.R.A. cred blob management "API". In order to allow S.A.R.A. to be stackable with other LSMs, it doesn't use the "security" field of struct cred, instead it uses an ad hoc field named security_sara. This solution is probably not acceptable for upstream, so this part will be modified as soon as the LSM stackable cred blob management will be available. Signed-off-by: Salvatore Mesoraca --- include/linux/cred.h | 3 ++ security/sara/Makefile | 2 +- security/sara/include/sara_data.h | 47 +++++++++++++++++++++++ security/sara/main.c | 6 +++ security/sara/sara_data.c | 79 +++++++++++++++++++++++++++++++++++++++ 5 files changed, 136 insertions(+), 1 deletion(-) create mode 100644 security/sara/include/sara_data.h create mode 100644 security/sara/sara_data.c diff --git a/include/linux/cred.h b/include/linux/cred.h index 099058e..b65b666 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -141,6 +141,9 @@ struct cred { #ifdef CONFIG_SECURITY void *security; /* subjective LSM security */ #endif +#ifdef CONFIG_SECURITY_SARA + void *security_sara; +#endif struct user_struct *user; /* real user ID subscription */ struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */ struct group_info *group_info; /* supplementary groups for euid/fsgid */ diff --git a/security/sara/Makefile b/security/sara/Makefile index 8acd291..14bf7a8 100644 --- a/security/sara/Makefile +++ b/security/sara/Makefile @@ -1,3 +1,3 @@ obj-$(CONFIG_SECURITY_SARA) := sara.o -sara-y := main.o securityfs.o utils.o +sara-y := main.o securityfs.o utils.o sara_data.o diff --git a/security/sara/include/sara_data.h b/security/sara/include/sara_data.h new file mode 100644 index 0000000..7ed04fd --- /dev/null +++ b/security/sara/include/sara_data.h @@ -0,0 +1,47 @@ +/* + * S.A.R.A. Linux Security Module + * + * Copyright (C) 2017 Salvatore Mesoraca + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2, as + * published by the Free Software Foundation. + * + */ + +#ifndef __SARA_DATA_H +#define __SARA_DATA_H + +#include + +int sara_data_init(void) __init; + +#ifdef CONFIG_SECURITY_SARA_WXPROT + +struct sara_data { + unsigned long relro_page; + u16 wxp_flags; + bool relro_page_found; + bool mmap_blocked; +}; + +#define get_sara_data_leftvalue(X) ((X)->security_sara) +#define get_sara_data(X) ((struct sara_data *) (X)->security_sara) +#define get_current_sara_data() get_sara_data(current_cred()) + +#define get_sara_wxp_flags(X) (get_sara_data((X))->wxp_flags) +#define get_current_sara_wxp_flags() get_sara_wxp_flags(current_cred()) + +#define get_sara_relro_page(X) (get_sara_data((X))->relro_page) +#define get_current_sara_relro_page() get_sara_relro_page(current_cred()) + +#define get_sara_relro_page_found(X) (get_sara_data((X))->relro_page_found) +#define get_current_sara_relro_page_found() \ + get_sara_relro_page_found(current_cred()) + +#define get_sara_mmap_blocked(X) (get_sara_data((X))->mmap_blocked) +#define get_current_sara_mmap_blocked() get_sara_mmap_blocked(current_cred()) + +#endif + +#endif /* __SARA_H */ diff --git a/security/sara/main.c b/security/sara/main.c index aaddd32..0fc1761 100644 --- a/security/sara/main.c +++ b/security/sara/main.c @@ -15,6 +15,7 @@ #include #include "include/sara.h" +#include "include/sara_data.h" #include "include/securityfs.h" static const int sara_version = SARA_VERSION; @@ -90,6 +91,11 @@ void __init sara_init(void) goto error; } + if (sara_data_init()) { + pr_crit("impossible to initialize creds.\n"); + goto error; + } + pr_debug("initialized.\n"); if (sara_enabled) diff --git a/security/sara/sara_data.c b/security/sara/sara_data.c new file mode 100644 index 0000000..8f11cd1 --- /dev/null +++ b/security/sara/sara_data.c @@ -0,0 +1,79 @@ +/* + * S.A.R.A. Linux Security Module + * + * Copyright (C) 2017 Salvatore Mesoraca + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2, as + * published by the Free Software Foundation. + * + */ + +#include "include/sara_data.h" + +#ifdef CONFIG_SECURITY_SARA_WXPROT +#include +#include +#include + +static int sara_cred_alloc_blank(struct cred *cred, gfp_t gfp) +{ + struct sara_data *d; + + d = kzalloc(sizeof(*d), gfp); + if (d == NULL) + return -ENOMEM; + get_sara_data_leftvalue(cred) = d; + return 0; +} + +static void sara_cred_free(struct cred *cred) +{ + struct sara_data *d; + + d = get_sara_data(cred); + if (d != NULL) { + kfree(d); + get_sara_data_leftvalue(cred) = NULL; + } +} + +static int sara_cred_prepare(struct cred *new, const struct cred *old, + gfp_t gfp) +{ + struct sara_data *d; + + d = kmemdup(get_sara_data(old), sizeof(*d), gfp); + if (d == NULL) + return -ENOMEM; + get_sara_data_leftvalue(new) = d; + return 0; +} + +static void sara_cred_transfer(struct cred *new, const struct cred *old) +{ + *get_sara_data(new) = *get_sara_data(old); +} + +static struct security_hook_list data_hooks[] __ro_after_init = { + LSM_HOOK_INIT(cred_alloc_blank, sara_cred_alloc_blank), + LSM_HOOK_INIT(cred_free, sara_cred_free), + LSM_HOOK_INIT(cred_prepare, sara_cred_prepare), + LSM_HOOK_INIT(cred_transfer, sara_cred_transfer), +}; + +int __init sara_data_init(void) +{ + security_add_hooks(data_hooks, ARRAY_SIZE(data_hooks), "sara"); + return sara_cred_alloc_blank((struct cred *) current->real_cred, + GFP_KERNEL); +} + +#else /* CONFIG_SECURITY_SARA_WXPROT */ + +int __init sara_data_init(void) +{ + return 0; +} + +#endif