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-rw-r--r--drivers/md/Makefile4
-rw-r--r--drivers/md/dm-core.h5
-rw-r--r--drivers/md/dm-ima.c330
-rw-r--r--drivers/md/dm-ima.h59
-rw-r--r--drivers/md/dm-ioctl.c7
-rw-r--r--drivers/md/dm.c3
-rw-r--r--include/linux/device-mapper.h2
-rw-r--r--include/uapi/linux/dm-ioctl.h6
-rw-r--r--security/integrity/ima/ima_main.c1
9 files changed, 415 insertions, 2 deletions
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index a74aaf8b1445..816945eeed7f 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -96,6 +96,10 @@ ifeq ($(CONFIG_BLK_DEV_ZONED),y)
dm-mod-objs += dm-zone.o
endif
+ifeq ($(CONFIG_IMA),y)
+dm-mod-objs += dm-ima.o
+endif
+
ifeq ($(CONFIG_DM_VERITY_FEC),y)
dm-verity-objs += dm-verity-fec.o
endif
diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index edc1553c4eea..55dccdfbcb22 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -18,6 +18,7 @@
#include <trace/events/block.h>
#include "dm.h"
+#include "dm-ima.h"
#define DM_RESERVED_MAX_IOS 1024
@@ -119,6 +120,10 @@ struct mapped_device {
unsigned int nr_zones;
unsigned int *zwp_offset;
#endif
+
+#ifdef CONFIG_IMA
+ struct dm_ima_measurements ima;
+#endif
};
/*
diff --git a/drivers/md/dm-ima.c b/drivers/md/dm-ima.c
new file mode 100644
index 000000000000..c8f54d9f6c8d
--- /dev/null
+++ b/drivers/md/dm-ima.c
@@ -0,0 +1,330 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 Microsoft Corporation
+ *
+ * Author: Tushar Sugandhi <tusharsu@linux.microsoft.com>
+ *
+ * File: dm-ima.c
+ * Enables IMA measurements for DM targets
+ */
+
+#include "dm-core.h"
+#include "dm-ima.h"
+
+#include <linux/ima.h>
+#include <crypto/hash.h>
+#include <linux/crypto.h>
+#include <crypto/hash_info.h>
+
+#define DM_MSG_PREFIX "ima"
+
+/*
+ * Internal function to prefix separator characters in input buffer with escape
+ * character, so that they don't interfere with the construction of key-value pairs,
+ * and clients can split the key1=val1,key2=val2,key3=val3; pairs properly.
+ */
+static void fix_separator_chars(char **buf)
+{
+ int l = strlen(*buf);
+ int i, j, sp = 0;
+
+ for (i = 0; i < l; i++)
+ if ((*buf)[i] == '\\' || (*buf)[i] == ';' || (*buf)[i] == '=' || (*buf)[i] == ',')
+ sp++;
+
+ if (!sp)
+ return;
+
+ for (i = l-1, j = i+sp; i >= 0; i--) {
+ (*buf)[j--] = (*buf)[i];
+ if ((*buf)[i] == '\\' || (*buf)[i] == ';' || (*buf)[i] == '=' || (*buf)[i] == ',')
+ (*buf)[j--] = '\\';
+ }
+}
+
+/*
+ * Internal function to allocate memory for IMA measurements.
+ */
+static void *dm_ima_alloc(size_t len, gfp_t flags, bool noio)
+{
+ unsigned int noio_flag;
+ void *ptr;
+
+ if (noio)
+ noio_flag = memalloc_noio_save();
+
+ ptr = kzalloc(len, flags);
+
+ if (noio)
+ memalloc_noio_restore(noio_flag);
+
+ return ptr;
+}
+
+/*
+ * Internal function to allocate and copy name and uuid for IMA measurements.
+ */
+static int dm_ima_alloc_and_copy_name_uuid(struct mapped_device *md, char **dev_name,
+ char **dev_uuid, bool noio)
+{
+ int r;
+ *dev_name = dm_ima_alloc(DM_NAME_LEN*2, GFP_KERNEL, noio);
+ if (!(*dev_name)) {
+ r = -ENOMEM;
+ goto error;
+ }
+
+ *dev_uuid = dm_ima_alloc(DM_UUID_LEN*2, GFP_KERNEL, noio);
+ if (!(*dev_uuid)) {
+ r = -ENOMEM;
+ goto error;
+ }
+
+ r = dm_copy_name_and_uuid(md, *dev_name, *dev_uuid);
+ if (r)
+ goto error;
+
+ fix_separator_chars(dev_name);
+ fix_separator_chars(dev_uuid);
+
+ return 0;
+error:
+ kfree(*dev_name);
+ kfree(*dev_uuid);
+ *dev_name = NULL;
+ *dev_uuid = NULL;
+ return r;
+}
+
+/*
+ * Internal function to allocate and copy device data for IMA measurements.
+ */
+static int dm_ima_alloc_and_copy_device_data(struct mapped_device *md, char **device_data,
+ unsigned int num_targets, bool noio)
+{
+ char *dev_name = NULL, *dev_uuid = NULL;
+ int r;
+
+ r = dm_ima_alloc_and_copy_name_uuid(md, &dev_name, &dev_uuid, noio);
+ if (r)
+ return r;
+
+ *device_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN, GFP_KERNEL, noio);
+ if (!(*device_data)) {
+ r = -ENOMEM;
+ goto error;
+ }
+
+ scnprintf(*device_data, DM_IMA_DEVICE_BUF_LEN,
+ "name=%s,uuid=%s,major=%d,minor=%d,minor_count=%d,num_targets=%u;",
+ dev_name, dev_uuid, md->disk->major, md->disk->first_minor,
+ md->disk->minors, num_targets);
+error:
+ kfree(dev_name);
+ kfree(dev_uuid);
+ return r;
+}
+
+/*
+ * Internal wrapper function to call IMA to measure DM data.
+ */
+static void dm_ima_measure_data(const char *event_name, const void *buf, size_t buf_len,
+ bool noio)
+{
+ unsigned int noio_flag;
+
+ if (noio)
+ noio_flag = memalloc_noio_save();
+
+ ima_measure_critical_data(DM_NAME, event_name, buf, buf_len, false);
+
+ if (noio)
+ memalloc_noio_restore(noio_flag);
+}
+
+/*
+ * Initialize/reset the dm ima related data structure variables.
+ */
+void dm_ima_reset_data(struct mapped_device *md)
+{
+ memset(&(md->ima), 0, sizeof(md->ima));
+}
+
+/*
+ * Build up the IMA data for each target, and finally measure.
+ */
+void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_flags)
+{
+ size_t device_data_buf_len, target_metadata_buf_len, target_data_buf_len, l = 0;
+ char *target_metadata_buf = NULL, *target_data_buf = NULL, *digest_buf = NULL;
+ char *ima_buf = NULL, *device_data_buf = NULL;
+ int digest_size, last_target_measured = -1, r;
+ status_type_t type = STATUSTYPE_IMA;
+ size_t cur_total_buf_len = 0;
+ unsigned int num_targets, i;
+ SHASH_DESC_ON_STACK(shash, NULL);
+ struct crypto_shash *tfm = NULL;
+ u8 *digest = NULL;
+ bool noio = false;
+
+ ima_buf = dm_ima_alloc(DM_IMA_MEASUREMENT_BUF_LEN, GFP_KERNEL, noio);
+ if (!ima_buf)
+ return;
+
+ target_metadata_buf = dm_ima_alloc(DM_IMA_TARGET_METADATA_BUF_LEN, GFP_KERNEL, noio);
+ if (!target_metadata_buf)
+ goto error;
+
+ target_data_buf = dm_ima_alloc(DM_IMA_TARGET_DATA_BUF_LEN, GFP_KERNEL, noio);
+ if (!target_data_buf)
+ goto error;
+
+ num_targets = dm_table_get_num_targets(table);
+
+ if (dm_ima_alloc_and_copy_device_data(table->md, &device_data_buf, num_targets, noio))
+ goto error;
+
+ tfm = crypto_alloc_shash("sha256", 0, 0);
+ if (IS_ERR(tfm))
+ goto error;
+
+ shash->tfm = tfm;
+ digest_size = crypto_shash_digestsize(tfm);
+ digest = dm_ima_alloc(digest_size, GFP_KERNEL, noio);
+ if (!digest)
+ goto error;
+
+ r = crypto_shash_init(shash);
+ if (r)
+ goto error;
+
+ device_data_buf_len = strlen(device_data_buf);
+ memcpy(ima_buf + l, device_data_buf, device_data_buf_len);
+ l += device_data_buf_len;
+
+ for (i = 0; i < num_targets; i++) {
+ struct dm_target *ti = dm_table_get_target(table, i);
+
+ if (!ti)
+ goto error;
+
+ last_target_measured = 0;
+
+ /*
+ * First retrieve the target metadata.
+ */
+ scnprintf(target_metadata_buf, DM_IMA_TARGET_METADATA_BUF_LEN,
+ "target_index=%d,target_begin=%llu,target_len=%llu,",
+ i, ti->begin, ti->len);
+ target_metadata_buf_len = strlen(target_metadata_buf);
+
+ /*
+ * Then retrieve the actual target data.
+ */
+ if (ti->type->status)
+ ti->type->status(ti, type, status_flags, target_data_buf,
+ DM_IMA_TARGET_DATA_BUF_LEN);
+ else
+ target_data_buf[0] = '\0';
+
+ target_data_buf_len = strlen(target_data_buf);
+
+ /*
+ * Check if the total data can fit into the IMA buffer.
+ */
+ cur_total_buf_len = l + target_metadata_buf_len + target_data_buf_len;
+
+ /*
+ * IMA measurements for DM targets are best-effort.
+ * If the total data buffered so far, including the current target,
+ * is too large to fit into DM_IMA_MEASUREMENT_BUF_LEN, measure what
+ * we have in the current buffer, and continue measuring the remaining
+ * targets by prefixing the device metadata again.
+ */
+ if (unlikely(cur_total_buf_len >= DM_IMA_MEASUREMENT_BUF_LEN)) {
+ dm_ima_measure_data("table_load", ima_buf, l, noio);
+ r = crypto_shash_update(shash, (const u8 *)ima_buf, l);
+ if (r < 0)
+ goto error;
+
+ memset(ima_buf, 0, DM_IMA_MEASUREMENT_BUF_LEN);
+ l = 0;
+
+ /*
+ * Each new "table_load" entry in IMA log should have device data
+ * prefix, so that multiple records from the same table_load for
+ * a given device can be linked together.
+ */
+ memcpy(ima_buf + l, device_data_buf, device_data_buf_len);
+ l += device_data_buf_len;
+
+ /*
+ * If this iteration of the for loop turns out to be the last target
+ * in the table, dm_ima_measure_data("table_load", ...) doesn't need
+ * to be called again, just the hash needs to be finalized.
+ * "last_target_measured" tracks this state.
+ */
+ last_target_measured = 1;
+ }
+
+ /*
+ * Fill-in all the target metadata, so that multiple targets for the same
+ * device can be linked together.
+ */
+ memcpy(ima_buf + l, target_metadata_buf, target_metadata_buf_len);
+ l += target_metadata_buf_len;
+
+ memcpy(ima_buf + l, target_data_buf, target_data_buf_len);
+ l += target_data_buf_len;
+ }
+
+ if (!last_target_measured) {
+ dm_ima_measure_data("table_load", ima_buf, l, noio);
+
+ r = crypto_shash_update(shash, (const u8 *)ima_buf, l);
+ if (r < 0)
+ goto error;
+ }
+
+ /*
+ * Finalize the table hash, and store it in table->md->ima.inactive_table.hash,
+ * so that the table data can be verified against the future device state change
+ * events, e.g. resume, rename, remove, table-clear etc.
+ */
+ r = crypto_shash_final(shash, digest);
+ if (r < 0)
+ goto error;
+
+ digest_buf = dm_ima_alloc((digest_size*2)+1, GFP_KERNEL, noio);
+ if (!digest_buf)
+ goto error;
+
+ for (i = 0; i < digest_size; i++)
+ snprintf((digest_buf+(i*2)), 3, "%02x", digest[i]);
+
+ if (table->md->ima.active_table.hash != table->md->ima.inactive_table.hash)
+ kfree(table->md->ima.inactive_table.hash);
+
+ table->md->ima.inactive_table.hash = digest_buf;
+ table->md->ima.inactive_table.hash_len = strlen(digest_buf);
+ table->md->ima.inactive_table.num_targets = num_targets;
+
+ if (table->md->ima.active_table.device_metadata !=
+ table->md->ima.inactive_table.device_metadata)
+ kfree(table->md->ima.inactive_table.device_metadata);
+
+ table->md->ima.inactive_table.device_metadata = device_data_buf;
+ table->md->ima.inactive_table.device_metadata_len = device_data_buf_len;
+
+ goto exit;
+error:
+ kfree(digest_buf);
+ kfree(device_data_buf);
+exit:
+ kfree(digest);
+ if (tfm)
+ crypto_free_shash(tfm);
+ kfree(ima_buf);
+ kfree(target_metadata_buf);
+ kfree(target_data_buf);
+}
diff --git a/drivers/md/dm-ima.h b/drivers/md/dm-ima.h
new file mode 100644
index 000000000000..16afd9a8c0b2
--- /dev/null
+++ b/drivers/md/dm-ima.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2021 Microsoft Corporation
+ *
+ * Author: Tushar Sugandhi <tusharsu@linux.microsoft.com>
+ *
+ * File: dm-ima.h
+ * Header file for device mapper IMA measurements.
+ */
+
+#ifndef DM_IMA_H
+#define DM_IMA_H
+
+#define DM_IMA_MEASUREMENT_BUF_LEN 4096
+#define DM_IMA_DEVICE_BUF_LEN 1024
+#define DM_IMA_TARGET_METADATA_BUF_LEN 128
+#define DM_IMA_TARGET_DATA_BUF_LEN 2048
+
+#ifdef CONFIG_IMA
+
+struct dm_ima_device_table_metadata {
+ /*
+ * Contains data specific to the device which is common across
+ * all the targets in the table (e.g. name, uuid, major, minor, etc).
+ * The values are stored in comma separated list of key1=val1,key2=val2;
+ * pairs delimited by a semicolon at the end of the list.
+ */
+ char *device_metadata;
+ unsigned int device_metadata_len;
+ unsigned int num_targets;
+
+ /*
+ * Contains the sha256 hashes of the IMA measurements of the target
+ * attributes' key-value pairs from the active/inactive tables.
+ */
+ char *hash;
+ unsigned int hash_len;
+};
+
+/*
+ * This structure contains device metadata, and table hash for
+ * active and inactive tables for ima measurements.
+ */
+struct dm_ima_measurements {
+ struct dm_ima_device_table_metadata active_table;
+ struct dm_ima_device_table_metadata inactive_table;
+};
+
+void dm_ima_reset_data(struct mapped_device *md);
+void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_flags);
+
+#else
+
+static inline void dm_ima_reset_data(struct mapped_device *md) {}
+static inline void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_flags) {}
+
+#endif /* CONFIG_IMA */
+
+#endif /* DM_IMA_H */
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 2575074a2204..d7c3456bf858 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -6,7 +6,7 @@
*/
#include "dm-core.h"
-
+#include "dm-ima.h"
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/miscdevice.h>
@@ -20,6 +20,7 @@
#include <linux/compat.h>
#include <linux/uaccess.h>
+#include <linux/ima.h>
#define DM_MSG_PREFIX "ioctl"
#define DM_DRIVER_EMAIL "dm-devel@redhat.com"
@@ -1224,6 +1225,8 @@ static void retrieve_status(struct dm_table *table,
if (param->flags & DM_STATUS_TABLE_FLAG)
type = STATUSTYPE_TABLE;
+ else if (param->flags & DM_IMA_MEASUREMENT_FLAG)
+ type = STATUSTYPE_IMA;
else
type = STATUSTYPE_INFO;
@@ -1425,6 +1428,8 @@ static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_si
if (r)
goto err_unlock_md_type;
+ dm_ima_measure_on_table_load(t, STATUSTYPE_IMA);
+
immutable_target_type = dm_get_immutable_target_type(md);
if (immutable_target_type &&
(immutable_target_type != dm_table_get_immutable_target_type(t)) &&
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7981b7287628..33e55ac9ec65 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -8,6 +8,7 @@
#include "dm-core.h"
#include "dm-rq.h"
#include "dm-uevent.h"
+#include "dm-ima.h"
#include <linux/init.h>
#include <linux/module.h>
@@ -1997,6 +1998,8 @@ int dm_create(int minor, struct mapped_device **result)
if (!md)
return -ENXIO;
+ dm_ima_reset_data(md);
+
*result = md;
return 0;
}
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 7457d49acf9a..74486c332946 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -31,7 +31,7 @@ enum dm_queue_mode {
DM_TYPE_DAX_BIO_BASED = 3,
};
-typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
+typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE, STATUSTYPE_IMA } status_type_t;
union map_info {
void *ptr;
diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h
index e5c6e458bdf7..c12ce30b52df 100644
--- a/include/uapi/linux/dm-ioctl.h
+++ b/include/uapi/linux/dm-ioctl.h
@@ -376,4 +376,10 @@ enum {
*/
#define DM_INTERNAL_SUSPEND_FLAG (1 << 18) /* Out */
+/*
+ * If set, returns in the in buffer passed by UM, the raw table information
+ * that would be measured by IMA subsystem on device state change.
+ */
+#define DM_IMA_MEASUREMENT_FLAG (1 << 19) /* In */
+
#endif /* _LINUX_DM_IOCTL_H */
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 287b90509006..673833f94069 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -985,6 +985,7 @@ void ima_measure_critical_data(const char *event_label,
CRITICAL_DATA, 0, event_label,
hash);
}
+EXPORT_SYMBOL_GPL(ima_measure_critical_data);
static int __init init_ima(void)
{