@@ -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 <linux/stat.h>
@@ -324,6 +325,11 @@ static struct inode *bdev_alloc_inode(struct super_block *sb)
if (!ei)
return NULL;
memset(&ei->bdev, 0, sizeof(ei->bdev));
+
+ if (security_bdev_alloc(&ei->bdev)) {
+ kmem_cache_free(bdev_cachep, ei);
+ return NULL;
+ }
return &ei->vfs_inode;
}
@@ -333,6 +339,7 @@ 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)
@@ -71,6 +71,9 @@ struct block_device {
struct partition_meta_info *bd_meta_info;
int bd_writers;
+#ifdef CONFIG_SECURITY
+ void *bd_security;
+#endif
/*
* keep this out-of-line as it's both big and not needed in the fast
* path
@@ -454,3 +454,8 @@ LSM_HOOK(int, 0, uring_cmd, struct io_uring_cmd *ioucmd)
#endif /* CONFIG_IO_URING */
LSM_HOOK(void, LSM_RET_VOID, initramfs_populated, void)
+
+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_setintegrity, struct block_device *bdev,
+ enum lsm_integrity_type type, const void *value, size_t size)
@@ -78,6 +78,7 @@ struct lsm_blob_sizes {
int lbs_msg_msg;
int lbs_task;
int lbs_xattr_count; /* number of xattr slots in new_xattrs array */
+ int lbs_bdev;
};
/**
@@ -83,6 +83,10 @@ enum lsm_event {
LSM_POLICY_CHANGE,
};
+enum lsm_integrity_type {
+ __LSM_INT_MAX
+};
+
/*
* These are reasons that can be passed to the security_locked_down()
* LSM hook. Lockdown reasons that protect kernel integrity (ie, the
@@ -509,6 +513,11 @@ int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
int security_locked_down(enum lockdown_reason what);
int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, u32 *uctx_len,
void *val, size_t val_len, u64 id, u64 flags);
+int security_bdev_alloc(struct block_device *bdev);
+void security_bdev_free(struct block_device *bdev);
+int security_bdev_setintegrity(struct block_device *bdev,
+ enum lsm_integrity_type type, const void *value,
+ size_t size);
#else /* CONFIG_SECURITY */
static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)
@@ -1483,6 +1492,23 @@ static inline int lsm_fill_user_ctx(struct lsm_ctx __user *uctx,
{
return -EOPNOTSUPP;
}
+
+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_setintegrity(struct block_device *bdev,
+ enum lsm_integrity_type type,
+ const void *value, size_t size)
+{
+ return 0;
+}
+
#endif /* CONFIG_SECURITY */
#if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)
@@ -29,6 +29,7 @@
#include <linux/msg.h>
#include <linux/overflow.h>
#include <net/flow.h>
+#include <linux/fs.h>
/* How many LSMs were built into the kernel? */
#define LSM_COUNT (__end_lsm_info - __start_lsm_info)
@@ -232,6 +233,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task);
lsm_set_blob_size(&needed->lbs_xattr_count,
&blob_sizes.lbs_xattr_count);
+ lsm_set_blob_size(&needed->lbs_bdev, &blob_sizes.lbs_bdev);
}
/* Prepare LSM for initialization. */
@@ -405,6 +407,7 @@ static void __init ordered_lsm_init(void)
init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
init_debug("task blob size = %d\n", blob_sizes.lbs_task);
init_debug("xattr slots = %d\n", blob_sizes.lbs_xattr_count);
+ init_debug("bdev blob size = %d\n", blob_sizes.lbs_bdev);
/*
* Create any kmem_caches needed for blobs
@@ -737,6 +740,28 @@ 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->bd_security = NULL;
+ return 0;
+ }
+
+ bdev->bd_security = kzalloc(blob_sizes.lbs_bdev, GFP_KERNEL);
+ if (!bdev->bd_security)
+ return -ENOMEM;
+
+ return 0;
+}
+
/**
* lsm_early_task - during initialization allocate a composite task blob
* @task: the task that needs a blob
@@ -5597,6 +5622,84 @@ int security_locked_down(enum lockdown_reason what)
}
EXPORT_SYMBOL(security_locked_down);
+/**
+ * security_bdev_alloc() - Allocate a block device LSM blob
+ * @bdev: block device
+ *
+ * Allocate and attach a security structure to @bdev->bd_security. The
+ * security field is initialized to NULL when the bdev structure is
+ * allocated.
+ *
+ * Return: Return 0 if operation was successful.
+ */
+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, bdev);
+ if (unlikely(rc))
+ security_bdev_free(bdev);
+
+ return rc;
+}
+EXPORT_SYMBOL(security_bdev_alloc);
+
+/**
+ * security_bdev_free() - Free a block device's LSM blob
+ * @bdev: block device
+ *
+ * Deallocate the bdev security structure and set @bdev->bd_security to NULL.
+ */
+void security_bdev_free(struct block_device *bdev)
+{
+ if (!bdev->bd_security)
+ return;
+
+ call_void_hook(bdev_free_security, bdev);
+
+ kfree(bdev->bd_security);
+ bdev->bd_security = NULL;
+}
+EXPORT_SYMBOL(security_bdev_free);
+
+/**
+ * security_bdev_setintegrity() - Set the device's integrity data
+ * @bdev: block device
+ * @type: type of integrity, e.g. hash digest, signature, etc
+ * @value: the integrity value
+ * @size: size of the integrity value
+ *
+ * Register a verified integrity measurement of a bdev with LSMs.
+ * LSMs should free the previously saved data if @value is NULL.
+ * Please note that the new hook should be invoked every time the security
+ * information is updated to keep these data current. For example, in dm-verity,
+ * if the mapping table is reloaded and configured to use a different dm-verity
+ * target with a new roothash and signing information, the previously stored data
+ * in the LSM blob will become obsolete. It is crucial to re-invoke the hook to
+ * refresh these data and ensure they are up to date. This necessity arises from
+ * the design of device-mapper, where a device-mapper device is first created, and
+ * then targets are subsequently loaded into it. These targets can be modified
+ * multiple times during the device's lifetime. Therefore, while the LSM blob is
+ * allocated during the creation of the block device, its actual contents are
+ * not initialized at this stage and can change substantially over time. This
+ * includes alterations from data that the LSMs 'trusts' to those they do not,
+ * making it essential to handle these changes correctly. Failure to address
+ * this dynamic aspect could potentially allow for bypassing LSM checks.
+ *
+ * Return: Returns 0 on success, negative values on failure.
+ */
+int security_bdev_setintegrity(struct block_device *bdev,
+ enum lsm_integrity_type type, const void *value,
+ size_t size)
+{
+ return call_int_hook(bdev_setintegrity, bdev, type, value, size);
+}
+EXPORT_SYMBOL(security_bdev_setintegrity);
+
#ifdef CONFIG_PERF_EVENTS
/**
* security_perf_event_open() - Check if a perf event open is allowed