---
v2:
+ No Changes
v3:
+ Minor style changes from checkpatch --strict
v4:
+ No Changes
v5:
+ Allow multiple callers to call security_bdev_setsecurity
v6:
+ Simplify security_bdev_setsecurity break condition
v7:
+ Squash all dm-verity related patches to two patches,
the additions to dm-verity/fs, and the consumption of
the additions.
v8:
+ Split dm-verity related patches squashed in v7 to 3 commits based on
topic:
+ New LSM hook
+ Consumption of hook outside LSM
+ Consumption of hook inside LSM.
+ change return of security_bdev_alloc / security_bdev_setsecurity
to LSM_RET_DEFAULT instead of 0.
+ Change return code to -EOPNOTSUPP, bring inline with other
setsecurity hooks.
---
block/bdev.c | 7 ++++
include/linux/blk_types.h | 1 +
include/linux/lsm_hook_defs.h | 5 +++
include/linux/lsm_hooks.h | 12 ++++++
include/linux/security.h | 22 +++++++++++
security/security.c | 70 +++++++++++++++++++++++++++++++++++
6 files changed, 117 insertions(+)
diff --git a/block/bdev.c b/block/bdev.c
index 5fe06c1f2def..e7ef2c7a22c9 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -24,6 +24,7 @@
#include <linux/pseudo_fs.h>
#include <linux/uio.h>
#include <linux/namei.h>
+#include <linux/security.h>
#include <linux/part_stat.h>
#include <linux/uaccess.h>
#include "../fs/internal.h"
@@ -397,6 +398,11 @@ static struct inode *bdev_alloc_inode(struct super_block *sb)
if (!ei)
return NULL;
memset(&ei->bdev, 0, sizeof(ei->bdev));
+
+ if (unlikely(security_bdev_alloc(&ei->bdev))) {
+ kmem_cache_free(bdev_cachep, ei);
+ return NULL;
+ }
return &ei->vfs_inode;
}
@@ -406,6 +412,7 @@ static void bdev_free_inode(struct inode *inode)
free_percpu(bdev->bd_stats);
kfree(bdev->bd_meta_info);
+ security_bdev_free(bdev);
if (!bdev_is_partition(bdev)) {
if (bdev->bd_disk && bdev->bd_disk->bdi)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index a24d4078fb21..a014ffa14b2d 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -68,6 +68,7 @@ struct block_device {
#ifdef CONFIG_FAIL_MAKE_REQUEST
bool bd_make_it_fail;
#endif
+ void *security;
} __randomize_layout;
#define bdev_whole(_bdev) \
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index eafa1d2489fd..3449c004bd84 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -407,3 +407,8 @@ LSM_HOOK(int, 0, perf_event_write, struct perf_event *event)
LSM_HOOK(int, 0, uring_override_creds, const struct cred *new)
LSM_HOOK(int, 0, uring_sqpoll, void)
#endif /* CONFIG_IO_URING */
+
+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 91c8146649f5..9f011d705ea8 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1550,6 +1550,17 @@
*
* @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 -EOPNOTSUPP.
+ *
* Security hooks for perf events
*
* @perf_event_open:
@@ -1610,6 +1621,7 @@ 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 7fc4e9f49f54..30b663de301f 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -473,6 +473,11 @@ 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)
@@ -1349,6 +1354,23 @@ 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 188b8f782220..59ec336788e8 100644
--- a/security/security.c
+++ b/security/security.c
@@ -29,6 +29,7 @@
#include <linux/string.h>
#include <linux/msg.h>
#include <net/flow.h>
+#include <linux/fs.h>
#define MAX_LSM_EVM_XATTR 2
@@ -208,6 +209,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg);
lsm_set_blob_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock);
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. */
@@ -344,6 +346,7 @@ static void __init ordered_lsm_init(void)
init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg);
init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
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
@@ -660,6 +663,28 @@ 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
@@ -2617,6 +2642,51 @@ 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 LSM_RET_DEFAULT(bdev_alloc_security);
+}
+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 && rc != -EOPNOTSUPP)
+ return rc;
+ }
+
+ return LSM_RET_DEFAULT(bdev_setsecurity);
+}
+EXPORT_SYMBOL(security_bdev_setsecurity);
+
#ifdef CONFIG_PERF_EVENTS
int security_perf_event_open(struct perf_event_attr *attr, int type)
{
