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

[Deven Bowers]

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 at 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