diff options
| -rw-r--r-- | Documentation/device-mapper/verity.txt | 131 | ||||
| -rw-r--r-- | drivers/md/dm-thin.c | 7 | ||||
| -rw-r--r-- | drivers/md/persistent-data/dm-space-map-checker.c | 54 | ||||
| -rw-r--r-- | drivers/md/persistent-data/dm-space-map-disk.c | 11 | ||||
| -rw-r--r-- | drivers/md/persistent-data/dm-transaction-manager.c | 11 |
5 files changed, 103 insertions, 111 deletions
diff --git a/Documentation/device-mapper/verity.txt b/Documentation/device-mapper/verity.txt index 32e48797a14..9884681535e 100644 --- a/Documentation/device-mapper/verity.txt +++ b/Documentation/device-mapper/verity.txt @@ -7,39 +7,39 @@ This target is read-only. Construction Parameters ======================= - <version> <dev> <hash_dev> <hash_start> + <version> <dev> <hash_dev> <data_block_size> <hash_block_size> <num_data_blocks> <hash_start_block> <algorithm> <digest> <salt> <version> - This is the version number of the on-disk format. + This is the type of the on-disk hash format. 0 is the original format used in the Chromium OS. - The salt is appended when hashing, digests are stored continuously and - the rest of the block is padded with zeros. + The salt is appended when hashing, digests are stored continuously and + the rest of the block is padded with zeros. 1 is the current format that should be used for new devices. - The salt is prepended when hashing and each digest is - padded with zeros to the power of two. + The salt is prepended when hashing and each digest is + padded with zeros to the power of two. <dev> - This is the device containing the data the integrity of which needs to be + This is the device containing data, the integrity of which needs to be checked. It may be specified as a path, like /dev/sdaX, or a device number, <major>:<minor>. <hash_dev> - This is the device that that supplies the hash tree data. It may be + This is the device that supplies the hash tree data. It may be specified similarly to the device path and may be the same device. If the - same device is used, the hash_start should be outside of the dm-verity - configured device size. + same device is used, the hash_start should be outside the configured + dm-verity device. <data_block_size> - The block size on a data device. Each block corresponds to one digest on - the hash device. + The block size on a data device in bytes. + Each block corresponds to one digest on the hash device. <hash_block_size> - The size of a hash block. + The size of a hash block in bytes. <num_data_blocks> The number of data blocks on the data device. Additional blocks are @@ -65,7 +65,7 @@ Construction Parameters Theory of operation =================== -dm-verity is meant to be setup as part of a verified boot path. This +dm-verity is meant to be set up as part of a verified boot path. This may be anything ranging from a boot using tboot or trustedgrub to just booting from a known-good device (like a USB drive or CD). @@ -73,20 +73,20 @@ When a dm-verity device is configured, it is expected that the caller has been authenticated in some way (cryptographic signatures, etc). After instantiation, all hashes will be verified on-demand during disk access. If they cannot be verified up to the root node of the -tree, the root hash, then the I/O will fail. This should identify +tree, the root hash, then the I/O will fail. This should detect tampering with any data on the device and the hash data. Cryptographic hashes are used to assert the integrity of the device on a -per-block basis. This allows for a lightweight hash computation on first read -into the page cache. Block hashes are stored linearly-aligned to the nearest -block the size of a page. +per-block basis. This allows for a lightweight hash computation on first read +into the page cache. Block hashes are stored linearly, aligned to the nearest +block size. Hash Tree --------- Each node in the tree is a cryptographic hash. If it is a leaf node, the hash -is of some block data on disk. If it is an intermediary node, then the hash is -of a number of child nodes. +of some data block on disk is calculated. If it is an intermediary node, +the hash of a number of child nodes is calculated. Each entry in the tree is a collection of neighboring nodes that fit in one block. The number is determined based on block_size and the size of the @@ -110,63 +110,23 @@ alg = sha256, num_blocks = 32768, block_size = 4096 On-disk format ============== -Below is the recommended on-disk format. The verity kernel code does not -read the on-disk header. It only reads the hash blocks which directly -follow the header. It is expected that a user-space tool will verify the -integrity of the verity_header and then call dmsetup with the correct -parameters. Alternatively, the header can be omitted and the dmsetup -parameters can be passed via the kernel command-line in a rooted chain -of trust where the command-line is verified. +The verity kernel code does not read the verity metadata on-disk header. +It only reads the hash blocks which directly follow the header. +It is expected that a user-space tool will verify the integrity of the +verity header. -The on-disk format is especially useful in cases where the hash blocks -are on a separate partition. The magic number allows easy identification -of the partition contents. Alternatively, the hash blocks can be stored -in the same partition as the data to be verified. In such a configuration -the filesystem on the partition would be sized a little smaller than -the full-partition, leaving room for the hash blocks. - -struct superblock { - uint8_t signature[8] - "verity\0\0"; - - uint8_t version; - 1 - current format - - uint8_t data_block_bits; - log2(data block size) - - uint8_t hash_block_bits; - log2(hash block size) - - uint8_t pad1[1]; - zero padding - - uint16_t salt_size; - big-endian salt size - - uint8_t pad2[2]; - zero padding - - uint32_t data_blocks_hi; - big-endian high 32 bits of the 64-bit number of data blocks - - uint32_t data_blocks_lo; - big-endian low 32 bits of the 64-bit number of data blocks - - uint8_t algorithm[16]; - cryptographic algorithm - - uint8_t salt[384]; - salt (the salt size is specified above) - - uint8_t pad3[88]; - zero padding to 512-byte boundary -} +Alternatively, the header can be omitted and the dmsetup parameters can +be passed via the kernel command-line in a rooted chain of trust where +the command-line is verified. Directly following the header (and with sector number padded to the next hash block boundary) are the hash blocks which are stored a depth at a time (starting from the root), sorted in order of increasing index. +The full specification of kernel parameters and on-disk metadata format +is available at the cryptsetup project's wiki page + http://code.google.com/p/cryptsetup/wiki/DMVerity + Status ====== V (for Valid) is returned if every check performed so far was valid. @@ -174,21 +134,22 @@ If any check failed, C (for Corruption) is returned. Example ======= - -Setup a device: - dmsetup create vroot --table \ - "0 2097152 "\ - "verity 1 /dev/sda1 /dev/sda2 4096 4096 2097152 1 "\ +Set up a device: + # dmsetup create vroot --readonly --table \ + "0 2097152 verity 1 /dev/sda1 /dev/sda2 4096 4096 262144 1 sha256 "\ "4392712ba01368efdf14b05c76f9e4df0d53664630b5d48632ed17a137f39076 "\ "1234000000000000000000000000000000000000000000000000000000000000" A command line tool veritysetup is available to compute or verify -the hash tree or activate the kernel driver. This is available from -the LVM2 upstream repository and may be supplied as a package called -device-mapper-verity-tools: - git://sources.redhat.com/git/lvm2 - http://sourceware.org/git/?p=lvm2.git - http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/verity?cvsroot=lvm2 - -veritysetup -a vroot /dev/sda1 /dev/sda2 \ - 4392712ba01368efdf14b05c76f9e4df0d53664630b5d48632ed17a137f39076 +the hash tree or activate the kernel device. This is available from +the cryptsetup upstream repository http://code.google.com/p/cryptsetup/ +(as a libcryptsetup extension). + +Create hash on the device: + # veritysetup format /dev/sda1 /dev/sda2 + ... + Root hash: 4392712ba01368efdf14b05c76f9e4df0d53664630b5d48632ed17a137f39076 + +Activate the device: + # veritysetup create vroot /dev/sda1 /dev/sda2 \ + 4392712ba01368efdf14b05c76f9e4df0d53664630b5d48632ed17a137f39076 diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 37fdaf81bd1..ce59824fb41 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -2292,6 +2292,13 @@ static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct if (r) return r; + r = dm_pool_commit_metadata(pool->pmd); + if (r) { + DMERR("%s: dm_pool_commit_metadata() failed, error = %d", + __func__, r); + return r; + } + r = dm_pool_reserve_metadata_snap(pool->pmd); if (r) DMWARN("reserve_metadata_snap message failed."); diff --git a/drivers/md/persistent-data/dm-space-map-checker.c b/drivers/md/persistent-data/dm-space-map-checker.c index 50ed53bf4aa..fc90c11620a 100644 --- a/drivers/md/persistent-data/dm-space-map-checker.c +++ b/drivers/md/persistent-data/dm-space-map-checker.c @@ -8,6 +8,7 @@ #include <linux/device-mapper.h> #include <linux/export.h> +#include <linux/vmalloc.h> #ifdef CONFIG_DM_DEBUG_SPACE_MAPS @@ -89,13 +90,23 @@ static int ca_create(struct count_array *ca, struct dm_space_map *sm) ca->nr = nr_blocks; ca->nr_free = nr_blocks; - ca->counts = kzalloc(sizeof(*ca->counts) * nr_blocks, GFP_KERNEL); - if (!ca->counts) - return -ENOMEM; + + if (!nr_blocks) + ca->counts = NULL; + else { + ca->counts = vzalloc(sizeof(*ca->counts) * nr_blocks); + if (!ca->counts) + return -ENOMEM; + } return 0; } +static void ca_destroy(struct count_array *ca) +{ + vfree(ca->counts); +} + static int ca_load(struct count_array *ca, struct dm_space_map *sm) { int r; @@ -126,12 +137,14 @@ static int ca_load(struct count_array *ca, struct dm_space_map *sm) static int ca_extend(struct count_array *ca, dm_block_t extra_blocks) { dm_block_t nr_blocks = ca->nr + extra_blocks; - uint32_t *counts = kzalloc(sizeof(*counts) * nr_blocks, GFP_KERNEL); + uint32_t *counts = vzalloc(sizeof(*counts) * nr_blocks); if (!counts) return -ENOMEM; - memcpy(counts, ca->counts, sizeof(*counts) * ca->nr); - kfree(ca->counts); + if (ca->counts) { + memcpy(counts, ca->counts, sizeof(*counts) * ca->nr); + ca_destroy(ca); + } ca->nr = nr_blocks; ca->nr_free += extra_blocks; ca->counts = counts; @@ -151,11 +164,6 @@ static int ca_commit(struct count_array *old, struct count_array *new) return 0; } -static void ca_destroy(struct count_array *ca) -{ - kfree(ca->counts); -} - /*----------------------------------------------------------------*/ struct sm_checker { @@ -343,25 +351,25 @@ struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm) int r; struct sm_checker *smc; - if (!sm) - return NULL; + if (IS_ERR_OR_NULL(sm)) + return ERR_PTR(-EINVAL); smc = kmalloc(sizeof(*smc), GFP_KERNEL); if (!smc) - return NULL; + return ERR_PTR(-ENOMEM); memcpy(&smc->sm, &ops_, sizeof(smc->sm)); r = ca_create(&smc->old_counts, sm); if (r) { kfree(smc); - return NULL; + return ERR_PTR(r); } r = ca_create(&smc->counts, sm); if (r) { ca_destroy(&smc->old_counts); kfree(smc); - return NULL; + return ERR_PTR(r); } smc->real_sm = sm; @@ -371,7 +379,7 @@ struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm) ca_destroy(&smc->counts); ca_destroy(&smc->old_counts); kfree(smc); - return NULL; + return ERR_PTR(r); } r = ca_commit(&smc->old_counts, &smc->counts); @@ -379,7 +387,7 @@ struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm) ca_destroy(&smc->counts); ca_destroy(&smc->old_counts); kfree(smc); - return NULL; + return ERR_PTR(r); } return &smc->sm; @@ -391,25 +399,25 @@ struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm) int r; struct sm_checker *smc; - if (!sm) - return NULL; + if (IS_ERR_OR_NULL(sm)) + return ERR_PTR(-EINVAL); smc = kmalloc(sizeof(*smc), GFP_KERNEL); if (!smc) - return NULL; + return ERR_PTR(-ENOMEM); memcpy(&smc->sm, &ops_, sizeof(smc->sm)); r = ca_create(&smc->old_counts, sm); if (r) { kfree(smc); - return NULL; + return ERR_PTR(r); } r = ca_create(&smc->counts, sm); if (r) { ca_destroy(&smc->old_counts); kfree(smc); - return NULL; + return ERR_PTR(r); } smc->real_sm = sm; diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c index fc469ba9f62..3d0ed533288 100644 --- a/drivers/md/persistent-data/dm-space-map-disk.c +++ b/drivers/md/persistent-data/dm-space-map-disk.c @@ -290,7 +290,16 @@ struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, dm_block_t nr_blocks) { struct dm_space_map *sm = dm_sm_disk_create_real(tm, nr_blocks); - return dm_sm_checker_create_fresh(sm); + struct dm_space_map *smc; + + if (IS_ERR_OR_NULL(sm)) + return sm; + + smc = dm_sm_checker_create_fresh(sm); + if (IS_ERR(smc)) + dm_sm_destroy(sm); + + return smc; } EXPORT_SYMBOL_GPL(dm_sm_disk_create); diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c index 400fe144c0c..e5604b32d91 100644 --- a/drivers/md/persistent-data/dm-transaction-manager.c +++ b/drivers/md/persistent-data/dm-transaction-manager.c @@ -138,6 +138,9 @@ EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone); void dm_tm_destroy(struct dm_transaction_manager *tm) { + if (!tm->is_clone) + wipe_shadow_table(tm); + kfree(tm); } EXPORT_SYMBOL_GPL(dm_tm_destroy); @@ -344,8 +347,10 @@ static int dm_tm_create_internal(struct dm_block_manager *bm, } *sm = dm_sm_checker_create(inner); - if (!*sm) + if (IS_ERR(*sm)) { + r = PTR_ERR(*sm); goto bad2; + } } else { r = dm_bm_write_lock(dm_tm_get_bm(*tm), sb_location, @@ -364,8 +369,10 @@ static int dm_tm_create_internal(struct dm_block_manager *bm, } *sm = dm_sm_checker_create(inner); - if (!*sm) + if (IS_ERR(*sm)) { + r = PTR_ERR(*sm); goto bad2; + } } return 0; |