From patchwork Tue Jul 28 21:36:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Deven Bowers X-Patchwork-Id: 11689899 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 15180912 for ; Tue, 28 Jul 2020 21:37:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBADE20768 for ; Tue, 28 Jul 2020 21:37:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="S+D5bKJE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729580AbgG1Vg3 (ORCPT ); Tue, 28 Jul 2020 17:36:29 -0400 Received: from linux.microsoft.com ([13.77.154.182]:47292 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729505AbgG1Vg2 (ORCPT ); Tue, 28 Jul 2020 17:36:28 -0400 Received: from dede-linux-virt.corp.microsoft.com (unknown [131.107.160.54]) by linux.microsoft.com (Postfix) with ESMTPSA id D58C720B490E; Tue, 28 Jul 2020 14:36:27 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D58C720B490E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1595972188; bh=SC6FlQIH3oTzgF1y4D27CLLK+qOAyAobEQYvHVcHTHk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S+D5bKJEHEeORe6p0ptieKrrFuKRBHRW6qN8UsOllSrIINbMexMwHdoy4Kg73eQkP OTe1Kmkeoud8luOi4mCHdXScdJe3qQvd2Uw6OZmbgRugmK7GQQ4BUdcBZKI7o5GzNk mB+n13CQz6OJPcg31CF9Qb3/8GKWm7HboxL0dXEk= From: Deven Bowers To: agk@redhat.com, axboe@kernel.dk, snitzer@redhat.com, jmorris@namei.org, serge@hallyn.com, zohar@linux.ibm.com, viro@zeniv.linux.org.uk, paul@paul-moore.com, eparis@redhat.com, jannh@google.com, dm-devel@redhat.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-audit@redhat.com Cc: tyhicks@linux.microsoft.com, linux-kernel@vger.kernel.org, corbet@lwn.net, sashal@kernel.org, jaskarankhurana@linux.microsoft.com, mdsakib@microsoft.com, nramas@linux.microsoft.com, pasha.tatashin@soleen.com Subject: [RFC PATCH v5 05/11] fs: add security blob and hooks for block_device Date: Tue, 28 Jul 2020 14:36:05 -0700 Message-Id: <20200728213614.586312-6-deven.desai@linux.microsoft.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200728213614.586312-1-deven.desai@linux.microsoft.com> References: <20200728213614.586312-1-deven.desai@linux.microsoft.com> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Add a security blob and associated allocation, deallocation and set hooks for a block_device structure. Signed-off-by: Deven Bowers --- fs/block_dev.c | 8 ++++ include/linux/fs.h | 1 + include/linux/lsm_hook_defs.h | 5 +++ include/linux/lsm_hooks.h | 12 ++++++ include/linux/security.h | 22 +++++++++++ security/security.c | 74 +++++++++++++++++++++++++++++++++++ 6 files changed, 122 insertions(+) diff --git a/fs/block_dev.c b/fs/block_dev.c index 0ae656e022fd..8602dd62c3e2 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -34,6 +34,7 @@ #include #include #include +#include #include "internal.h" struct bdev_inode { @@ -768,11 +769,18 @@ static struct inode *bdev_alloc_inode(struct super_block *sb) struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); if (!ei) return NULL; + + if (unlikely(security_bdev_alloc(&ei->bdev))) { + kmem_cache_free(bdev_cachep, ei); + return NULL; + } + return &ei->vfs_inode; } static void bdev_free_inode(struct inode *inode) { + security_bdev_free(&BDEV_I(inode)->bdev); kmem_cache_free(bdev_cachep, BDEV_I(inode)); } diff --git a/include/linux/fs.h b/include/linux/fs.h index f5abba86107d..42d7e3ce7712 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -509,6 +509,7 @@ struct block_device { int bd_fsfreeze_count; /* Mutex for freeze */ struct mutex bd_fsfreeze_mutex; + void *security; } __randomize_layout; /* XArray tags, for tagging dirty and writeback pages in the pagecache. */ diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index af998f93d256..f3c0da0db4e8 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -391,3 +391,8 @@ LSM_HOOK(void, LSM_RET_VOID, perf_event_free, struct perf_event *event) LSM_HOOK(int, 0, perf_event_read, struct perf_event *event) LSM_HOOK(int, 0, perf_event_write, struct perf_event *event) #endif /* CONFIG_PERF_EVENTS */ + +LSM_HOOK(int, 0, bdev_alloc_security, struct block_device *bdev) +LSM_HOOK(void, LSM_RET_VOID, bdev_free_security, struct block_device *bdev) +LSM_HOOK(int, 0, bdev_setsecurity, struct block_device *bdev, const char *name, + const void *value, size_t size) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 95b7c1d32062..8670c19a8cef 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1507,6 +1507,17 @@ * * @what: kernel feature being accessed * + * @bdev_alloc_security: + * Initialize the security field inside a block_device structure. + * + * @bdev_free_security: + * Cleanup the security information stored inside a block_device structure. + * + * @bdev_setsecurity: + * Set a security property associated with @name for @bdev with + * value @value. @size indicates the size of @value in bytes. + * If a @name is not implemented, return -ENOSYS. + * * Security hooks for perf events * * @perf_event_open: @@ -1553,6 +1564,7 @@ struct lsm_blob_sizes { int lbs_ipc; int lbs_msg_msg; int lbs_task; + int lbs_bdev; }; /* diff --git a/include/linux/security.h b/include/linux/security.h index 0a0a03b36a3b..8f83fdc6c65d 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -451,6 +451,11 @@ int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen); int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen); int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen); int security_locked_down(enum lockdown_reason what); +int security_bdev_alloc(struct block_device *bdev); +void security_bdev_free(struct block_device *bdev); +int security_bdev_setsecurity(struct block_device *bdev, + const char *name, const void *value, + size_t size); #else /* CONFIG_SECURITY */ static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data) @@ -1291,6 +1296,23 @@ static inline int security_locked_down(enum lockdown_reason what) { return 0; } + +static inline int security_bdev_alloc(struct block_device *bdev) +{ + return 0; +} + +static inline void security_bdev_free(struct block_device *bdev) +{ +} + +static inline int security_bdev_setsecurity(struct block_device *bdev, + const char *name, + const void *value, size_t size) +{ + return 0; +} + #endif /* CONFIG_SECURITY */ #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE) diff --git a/security/security.c b/security/security.c index 70a7ad357bc6..fff445eba400 100644 --- a/security/security.c +++ b/security/security.c @@ -28,6 +28,7 @@ #include #include #include +#include #define MAX_LSM_EVM_XATTR 2 @@ -202,6 +203,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed) lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc); lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg); lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task); + lsm_set_blob_size(&needed->lbs_bdev, &blob_sizes.lbs_bdev); } /* Prepare LSM for initialization. */ @@ -337,6 +339,7 @@ static void __init ordered_lsm_init(void) init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc); init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg); init_debug("task blob size = %d\n", blob_sizes.lbs_task); + init_debug("bdev blob size = %d\n", blob_sizes.lbs_bdev); /* * Create any kmem_caches needed for blobs @@ -654,6 +657,28 @@ static int lsm_msg_msg_alloc(struct msg_msg *mp) return 0; } +/** + * lsm_bdev_alloc - allocate a composite block_device blob + * @bdev: the block_device that needs a blob + * + * Allocate the block_device blob for all the modules + * + * Returns 0, or -ENOMEM if memory can't be allocated. + */ +static int lsm_bdev_alloc(struct block_device *bdev) +{ + if (blob_sizes.lbs_bdev == 0) { + bdev->security = NULL; + return 0; + } + + bdev->security = kzalloc(blob_sizes.lbs_bdev, GFP_KERNEL); + if (!bdev->security) + return -ENOMEM; + + return 0; +} + /** * lsm_early_task - during initialization allocate a composite task blob * @task: the task that needs a blob @@ -2516,6 +2541,55 @@ int security_locked_down(enum lockdown_reason what) } EXPORT_SYMBOL(security_locked_down); +int security_bdev_alloc(struct block_device *bdev) +{ + int rc = 0; + + rc = lsm_bdev_alloc(bdev); + if (unlikely(rc)) + return rc; + + rc = call_int_hook(bdev_alloc_security, 0, bdev); + if (unlikely(rc)) + security_bdev_free(bdev); + + return 0; +} +EXPORT_SYMBOL(security_bdev_alloc); + +void security_bdev_free(struct block_device *bdev) +{ + if (!bdev->security) + return; + + call_void_hook(bdev_free_security, bdev); + + kfree(bdev->security); + bdev->security = NULL; +} +EXPORT_SYMBOL(security_bdev_free); + +int security_bdev_setsecurity(struct block_device *bdev, + const char *name, const void *value, + size_t size) +{ + int rc = 0; + struct security_hook_list *p; + + hlist_for_each_entry(p, &security_hook_heads.bdev_setsecurity, list) { + rc = p->hook.bdev_setsecurity(bdev, name, value, size); + + if (rc == -ENOSYS) + rc = 0; + + if (rc != 0) + break; + } + + return rc; +} +EXPORT_SYMBOL(security_bdev_setsecurity); + #ifdef CONFIG_PERF_EVENTS int security_perf_event_open(struct perf_event_attr *attr, int type) {