From: Sascha Hauer <s.hauer@pengutronix.de>
To: linux-mtd@lists.infradead.org
Cc: David Gstir <david@sigma-star.at>,
Richard Weinberger <richard@nod.at>,
kernel@pengutronix.de, linux-kernel@vger.kernel.org,
Sascha Hauer <s.hauer@pengutronix.de>
Subject: [PATCH 20/25] ubifs: authentication: Authenticate super block node
Date: Wed, 4 Jul 2018 14:41:32 +0200 [thread overview]
Message-ID: <20180704124137.13396-21-s.hauer@pengutronix.de> (raw)
In-Reply-To: <20180704124137.13396-1-s.hauer@pengutronix.de>
This adds a HMAC covering the super block node and adds the logic that
decides if a filesystem shall be mounted unauthenticated or
authenticated.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
fs/ubifs/sb.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index 155480f62fac..2e814b5fb5d1 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -517,6 +517,62 @@ static struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
return sup;
}
+static int authenticate_sb_node(struct ubifs_info *c,
+ const struct ubifs_sb_node *sup)
+{
+ unsigned int sup_flags = le32_to_cpu(sup->flags);
+ u8 hmac_wkm[UBIFS_MAX_HMAC_LEN];
+ int authenticated = !!(sup_flags & UBIFS_FLG_AUTHENTICATION);
+ int hash_algo;
+ int err;
+
+ if (c->authenticated && !authenticated) {
+ ubifs_err(c, "authenticated FS forced, but found FS without authentication");
+ return -EINVAL;
+ }
+
+ if (!c->authenticated && authenticated) {
+ ubifs_err(c, "authenticated FS found, but no key given");
+ return -EINVAL;
+ }
+
+ ubifs_msg(c, "Mounting in %sauthenticated mode",
+ c->authenticated ? "" : "un");
+
+ if (!c->authenticated)
+ return 0;
+
+ if (!IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION))
+ return -EOPNOTSUPP;
+
+ hash_algo = le16_to_cpu(sup->hash_algo);
+ if (hash_algo >= HASH_ALGO__LAST) {
+ ubifs_err(c, "superblock uses unknown hash algo %d",
+ hash_algo);
+ return -EINVAL;
+ }
+
+ if (strcmp(hash_algo_name[hash_algo], c->auth_hash_name)) {
+ ubifs_err(c, "This filesystem uses %s for hashing,"
+ " but %s is specified", hash_algo_name[hash_algo],
+ c->auth_hash_name);
+ return -EINVAL;
+ }
+
+ ubifs_hmac_wkm(c, hmac_wkm);
+ if (ubifs_check_hmac(c, hmac_wkm, sup->hmac_wkm)) {
+ ubifs_err(c, "provided key does not fit");
+ return -ENOKEY;
+ }
+
+ err = ubifs_node_verify_hmac(c, sup, sizeof(*sup),
+ offsetof(struct ubifs_sb_node, hmac));
+ if (err)
+ ubifs_err(c, "Failed to authenticate superblock: %d", err);
+
+ return err;
+}
+
/**
* ubifs_write_sb_node - write superblock node.
* @c: UBIFS file-system description object
@@ -528,7 +584,8 @@ int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
{
int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
- ubifs_prepare_node(c, sup, UBIFS_SB_NODE_SZ, 1);
+ ubifs_prepare_node_hmac(c, sup, UBIFS_SB_NODE_SZ,
+ offsetof(struct ubifs_sb_node, hmac), 1);
return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
}
@@ -642,6 +699,10 @@ int ubifs_read_superblock(struct ubifs_info *c)
c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);
+ err = authenticate_sb_node(c, sup);
+ if (err)
+ goto out;
+
if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
ubifs_err(c, "Unknown feature flags found: %#x",
sup_flags & ~UBIFS_FLG_MASK);
--
2.18.0
next prev parent reply other threads:[~2018-07-04 12:45 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-04 12:41 [PATCH 00/25] UBIFS authentication support Sascha Hauer
2018-07-04 12:41 ` [PATCH 01/25] ubifs: refactor create_default_filesystem() Sascha Hauer
2018-07-04 12:41 ` [PATCH 02/25] ubifs: pass ubifs_zbranch to try_read_node() Sascha Hauer
2018-07-04 12:41 ` [PATCH 03/25] ubifs: pass ubifs_zbranch to read_znode() Sascha Hauer
2018-07-04 12:41 ` [PATCH 04/25] ubifs: export pnode_lookup as ubifs_pnode_lookup Sascha Hauer
2018-07-04 12:41 ` [PATCH 05/25] ubifs: implement ubifs_lpt_lookup using ubifs_pnode_lookup Sascha Hauer
2018-08-13 6:31 ` Sascha Hauer
2018-08-13 6:34 ` Richard Weinberger
2018-08-13 8:12 ` Sascha Hauer
2018-08-13 11:30 ` Richard Weinberger
2018-08-26 20:59 ` Richard Weinberger
2018-07-04 12:41 ` [PATCH 06/25] ubifs: drop write_node Sascha Hauer
2018-07-04 12:41 ` [PATCH 07/25] ubifs: Store read superblock node Sascha Hauer
2018-08-27 12:50 ` Richard Weinberger
2018-07-04 12:41 ` [PATCH 08/25] ubifs: Format changes for authentication support Sascha Hauer
2018-07-04 12:41 ` [PATCH 09/25] ubifs: add separate functions to init/crc a node Sascha Hauer
2018-07-04 12:41 ` [PATCH 10/25] ubifs: add helper functions for authentication support Sascha Hauer
2018-08-27 12:50 ` Richard Weinberger
2018-08-29 6:30 ` Sascha Hauer
2018-07-04 12:41 ` [PATCH 11/25] ubifs: Create functions to embed a HMAC in a node Sascha Hauer
2018-07-04 12:41 ` [PATCH 12/25] ubifs: Add hashes to the tree node cache Sascha Hauer
2018-08-27 19:18 ` Richard Weinberger
2018-08-29 11:16 ` Sascha Hauer
2018-07-04 12:41 ` [PATCH 13/25] ubifs: authentication: Add hashes to index nodes Sascha Hauer
2018-08-27 19:36 ` Richard Weinberger
2018-09-07 10:25 ` Sascha Hauer
2018-07-04 12:41 ` [PATCH 14/25] ubifs: Add authentication nodes to journal Sascha Hauer
2018-07-08 2:59 ` kbuild test robot
2018-08-27 20:48 ` Richard Weinberger
2018-08-29 14:38 ` Sascha Hauer
2018-08-29 14:54 ` Richard Weinberger
2018-08-30 13:41 ` Sascha Hauer
2018-09-02 19:45 ` Richard Weinberger
2018-07-04 12:41 ` [PATCH 15/25] ubifs: Add auth nodes to garbage collector journal head Sascha Hauer
2018-08-27 20:51 ` Richard Weinberger
2018-08-30 14:43 ` Sascha Hauer
2018-07-04 12:41 ` [PATCH 16/25] ubifs: authenticate replayed journal Sascha Hauer
2018-07-08 6:08 ` kbuild test robot
2018-08-27 21:16 ` Richard Weinberger
2018-07-04 12:41 ` [PATCH 17/25] ubifs: authentication: authenticate LPT Sascha Hauer
2018-07-04 12:41 ` [PATCH 18/25] ubfis: authentication: authenticate master node Sascha Hauer
2018-07-04 12:41 ` [PATCH 19/25] ubifs: Create hash for default LPT Sascha Hauer
2018-07-04 12:41 ` Sascha Hauer [this message]
2018-07-04 12:41 ` [PATCH 21/25] ubifs: Add hashes and HMACs to default filesystem Sascha Hauer
2018-07-04 12:41 ` [PATCH 22/25] ubifs: do not update inode size in-place in authenticated mode Sascha Hauer
2018-07-04 12:41 ` [PATCH 23/25] ubifs: Enable authentication support Sascha Hauer
2018-07-04 12:41 ` [PATCH 24/25] ubifs: support offline signed images Sascha Hauer
2018-07-04 12:41 ` [PATCH 25/25] Documentation: ubifs: Add authentication whitepaper Sascha Hauer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180704124137.13396-21-s.hauer@pengutronix.de \
--to=s.hauer@pengutronix.de \
--cc=david@sigma-star.at \
--cc=kernel@pengutronix.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mtd@lists.infradead.org \
--cc=richard@nod.at \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).