[PATCH 22/25] ubifs: Add hashes and HMACs to default filesystem

From: Sascha Hauer
Date: Fri Sep 07 2018 - 08:39:49 EST


This patch calculates the necessary hashes and HMACs for the default
filesystem so that the dynamically created default fs can be
authenticated.

Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
fs/ubifs/sb.c | 34 +++++++++++++++++++++++++++-------
1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index 7f0967771c9f..ac1ed5ad126d 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -87,6 +87,7 @@ static int create_default_filesystem(struct ubifs_info *c)
__le64 tmp_le64;
__le32 tmp_le32;
struct timespec64 ts;
+ u8 hash[UBIFS_HASH_ARR_SZ];
u8 hash_lpt[UBIFS_HASH_ARR_SZ];

/* Some functions called from here depend on the @c->key_len filed */
@@ -177,6 +178,16 @@ static int create_default_filesystem(struct ubifs_info *c)
sup_flags |= UBIFS_FLG_BIGLPT;
sup_flags |= UBIFS_FLG_DOUBLE_HASH;

+ if (ubifs_authenticated(c)) {
+ sup_flags |= UBIFS_FLG_AUTHENTICATION;
+ sup->hash_algo = cpu_to_le16(c->auth_hash_algo);
+ err = ubifs_hmac_wkm(c, sup->hmac_wkm);
+ if (err)
+ goto out;
+ } else {
+ sup->hash_algo = 0xffff;
+ }
+
sup->ch.node_type = UBIFS_SB_NODE;
sup->key_hash = UBIFS_KEY_HASH_R5;
sup->flags = cpu_to_le32(sup_flags);
@@ -235,6 +246,7 @@ static int create_default_filesystem(struct ubifs_info *c)
mst->empty_lebs = cpu_to_le32(main_lebs - 2);
mst->idx_lebs = cpu_to_le32(1);
mst->leb_cnt = cpu_to_le32(c->leb_cnt);
+ ubifs_copy_hash(c, hash_lpt, mst->hash_lpt);

/* Calculate lprops statistics */
tmp64 = main_bytes;
@@ -307,25 +319,33 @@ static int create_default_filesystem(struct ubifs_info *c)

cs->ch.node_type = UBIFS_CS_NODE;

- err = ubifs_write_node(c, sup, UBIFS_SB_NODE_SZ, 0, 0);
+ err = ubifs_write_node_hmac(c, sup, UBIFS_SB_NODE_SZ, 0, 0,
+ offsetof(struct ubifs_sb_node, hmac));
if (err)
goto out;

- err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0);
+ err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
+ main_first + DEFAULT_DATA_LEB, 0);
if (err)
goto out;

- err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
- 0);
+ ubifs_node_calc_hash(c, ino, hash);
+ ubifs_copy_hash(c, hash, ubifs_branch_hash(c, br));
+
+ err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0);
if (err)
goto out;

- err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0);
+ ubifs_node_calc_hash(c, idx, hash);
+ ubifs_copy_hash(c, hash, mst->hash_root_idx);
+
+ err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0,
+ offsetof(struct ubifs_mst_node, hmac));
if (err)
goto out;

- err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
- main_first + DEFAULT_DATA_LEB, 0);
+ err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
+ 0, offsetof(struct ubifs_mst_node, hmac));
if (err)
goto out;

--
2.18.0