diff options
| -rw-r--r-- | drivers/md/Makefile | 4 | ||||
| -rw-r--r-- | drivers/md/dm-core.h | 5 | ||||
| -rw-r--r-- | drivers/md/dm-ima.c | 330 | ||||
| -rw-r--r-- | drivers/md/dm-ima.h | 59 | ||||
| -rw-r--r-- | drivers/md/dm-ioctl.c | 7 | ||||
| -rw-r--r-- | drivers/md/dm.c | 3 | ||||
| -rw-r--r-- | include/linux/device-mapper.h | 2 | ||||
| -rw-r--r-- | include/uapi/linux/dm-ioctl.h | 6 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 1 |
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) { |