fs: ubifs: Add authentication support

This adds UBIFS authentication support. For now, we do not do
any authentication even on authenticated UBIFS images. Since
this behaviour is not what the user normally expects when mounting
authenticated images we only do this when the user explicitly allows
it in "global.ubifs.allow_authenticated_unauthenticated". If the
flag is false then we refuse mounting such an image and return -EPERM
instead.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 20 insertions, 6 deletions

diff --git a/fs/ubifs/tnc_misc.c b/fs/ubifs/tnc_misc.c
index 3106c9d511..e8a8f45207 100644
--- a/fs/ubifs/tnc_misc.c
+++ b/fs/ubifs/tnc_misc.c
@@ -265,9 +265,7 @@ long ubifs_destroy_tnc_subtree(const struct ubifs_info *c,
 /**
  * read_znode - read an indexing node from flash and fill znode.
  * @c: UBIFS file-system description object
- * @lnum: LEB of the indexing node to read
- * @offs: node offset
- * @len: node length
+ * @zzbr: the zbranch describing the node to read
  * @znode: znode to read to
  *
  * This function reads an indexing node from the flash media and fills znode
@@ -276,9 +274,12 @@ long ubifs_destroy_tnc_subtree(const struct ubifs_info *c,
  * is wrong with it, this function prints complaint messages and returns
  * %-EINVAL.
  */
-static int read_znode(struct ubifs_info *c, int lnum, int offs, int len,
+static int read_znode(struct ubifs_info *c, struct ubifs_zbranch *zzbr,
 		      struct ubifs_znode *znode)
 {
+	int lnum = zzbr->lnum;
+	int offs = zzbr->offs;
+	int len = zzbr->len;
 	int i, err, type, cmp;
 	struct ubifs_idx_node *idx;
 
@@ -292,6 +293,12 @@ static int read_znode(struct ubifs_info *c, int lnum, int offs, int len,
 		return err;
 	}
 
+	err = ubifs_node_check_hash(c, idx, zzbr->hash);
+	if (err) {
+		ubifs_bad_hash(c, idx, zzbr->hash, lnum, offs);
+		return err;
+	}
+
 	znode->child_cnt = le16_to_cpu(idx->child_cnt);
 	znode->level = le16_to_cpu(idx->level);
 
@@ -308,13 +315,14 @@ static int read_znode(struct ubifs_info *c, int lnum, int offs, int len,
 	}
 
 	for (i = 0; i < znode->child_cnt; i++) {
-		const struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
+		struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
 		struct ubifs_zbranch *zbr = &znode->zbranch[i];
 
 		key_read(c, &br->key, &zbr->key);
 		zbr->lnum = le32_to_cpu(br->lnum);
 		zbr->offs = le32_to_cpu(br->offs);
 		zbr->len  = le32_to_cpu(br->len);
+		ubifs_copy_hash(c, ubifs_branch_hash(c, br), zbr->hash);
 		zbr->znode = NULL;
 
 		/* Validate branch */
@@ -425,7 +433,7 @@ struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,
 	if (!znode)
 		return ERR_PTR(-ENOMEM);
 
-	err = read_znode(c, zbr->lnum, zbr->offs, zbr->len, znode);
+	err = read_znode(c, zbr, znode);
 	if (err)
 		goto out;
 
@@ -484,5 +492,11 @@ int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr,
 		return -EINVAL;
 	}
 
+	err = ubifs_node_check_hash(c, node, zbr->hash);
+	if (err) {
+		ubifs_bad_hash(c, node, zbr->hash, zbr->lnum, zbr->offs);
+		return err;
+	}
+
 	return 0;
 }