[RFC PATCH v6 06/11] dm-verity: add bdev_setsecurity hook for dm-verity signature

Deven Bowers
2020-07-30T00:32:22Z

Add a security hook call to set a security property of a block_device
in dm-verity with the results of a verified, signed root-hash.

Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
---
drivers/md/dm-verity-target.c | 2 +-
drivers/md/dm-verity-verify-sig.c | 14 +++++++++++---
drivers/md/dm-verity-verify-sig.h | 10 ++++++----
include/linux/device-mapper.h | 2 ++
4 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index eec9f252e935..9970488e67ed 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1134,7 +1134,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
}

/* Root hash signature is a optional parameter*/
- r = verity_verify_root_hash(root_hash_digest_to_validate,
+ r = verity_verify_root_hash(v, root_hash_digest_to_validate,
strlen(root_hash_digest_to_validate),
verify_args.sig,
verify_args.sig_size);
diff --git a/drivers/md/dm-verity-verify-sig.c b/drivers/md/dm-verity-verify-sig.c
index 614e43db93aa..2cd9f8c85449 100644
--- a/drivers/md/dm-verity-verify-sig.c
+++ b/drivers/md/dm-verity-verify-sig.c
@@ -8,7 +8,10 @@
#include <linux/device-mapper.h>
#include <linux/verification.h>
#include <keys/user-type.h>
+#include <linux/security.h>
+#include <linux/list.h>
#include <linux/module.h>
+#include "dm-core.h"
#include "dm-verity.h"
#include "dm-verity-verify-sig.h"

@@ -103,8 +106,9 @@ int verity_verify_sig_parse_opt_args(struct dm_arg_set *as,
* @sig_len: Size of the signature.
*
*/
-int verity_verify_root_hash(const void *root_hash, size_t root_hash_len,
- const void *sig_data, size_t sig_len)
+int verity_verify_root_hash(struct dm_verity *v, const void *root_hash,
+ size_t root_hash_len, const void *sig_data,
+ size_t sig_len)
{
int ret;

@@ -121,8 +125,12 @@ int verity_verify_root_hash(const void *root_hash, size_t root_hash_len,
ret = verify_pkcs7_signature(root_hash, root_hash_len, sig_data,
sig_len, NULL, VERIFYING_UNSPECIFIED_SIGNATURE,
NULL, NULL);
+ if (ret)
+ return ret;

- return ret;
+ return security_bdev_setsecurity(dm_table_get_md(v->ti->table)->bdev,
+ DM_VERITY_SIGNATURE_SEC_NAME,
+ sig_data, sig_len);
}

void verity_verify_sig_opts_cleanup(struct dm_verity_sig_opts *sig_opts)
diff --git a/drivers/md/dm-verity-verify-sig.h b/drivers/md/dm-verity-verify-sig.h
index 19b1547aa741..6b7de1d48e5a 100644
--- a/drivers/md/dm-verity-verify-sig.h
+++ b/drivers/md/dm-verity-verify-sig.h
@@ -20,8 +20,9 @@ struct dm_verity_sig_opts {

#define DM_VERITY_ROOT_HASH_VERIFICATION_OPTS 2

-int verity_verify_root_hash(const void *data, size_t data_len,
- const void *sig_data, size_t sig_len);
+int verity_verify_root_hash(struct dm_verity *v, const void *data,
+ size_t data_len, const void *sig_data,
+ size_t sig_len);
bool verity_verify_is_sig_opt_arg(const char *arg_name);

int verity_verify_sig_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
@@ -34,8 +35,9 @@ void verity_verify_sig_opts_cleanup(struct dm_verity_sig_opts *sig_opts);

#define DM_VERITY_ROOT_HASH_VERIFICATION_OPTS 0

-int verity_verify_root_hash(const void *data, size_t data_len,
- const void *sig_data, size_t sig_len)
+int verity_verify_root_hash(struct dm_verity *v, const void *data,
+ size_t data_len, const void *sig_data,
+ size_t sig_len)
{
return 0;
}
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 73dec4b5d5be..ab6b8eb0a150 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -625,4 +625,6 @@ static inline unsigned long to_bytes(sector_t n)
return (n << SECTOR_SHIFT);
}

+#define DM_VERITY_SIGNATURE_SEC_NAME DM_NAME ".verity-sig"
+
#endif /* _LINUX_DEVICE_MAPPER_H */
--
2.27.0