From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/fs/ubifs/master.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 97 insertions(+), 19 deletions(-)
diff --git a/kernel/fs/ubifs/master.c b/kernel/fs/ubifs/master.c
index 9df4a41..911d055 100644
--- a/kernel/fs/ubifs/master.c
+++ b/kernel/fs/ubifs/master.c
@@ -1,20 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors: Artem Bityutskiy (Битюцкий Артём)
* Adrian Hunter
@@ -23,6 +11,72 @@
/* This file implements reading and writing the master node */
#include "ubifs.h"
+
+/**
+ * ubifs_compare_master_node - compare two UBIFS master nodes
+ * @c: UBIFS file-system description object
+ * @m1: the first node
+ * @m2: the second node
+ *
+ * This function compares two UBIFS master nodes. Returns 0 if they are equal
+ * and nonzero if not.
+ */
+int ubifs_compare_master_node(struct ubifs_info *c, void *m1, void *m2)
+{
+ int ret;
+ int behind;
+ int hmac_offs = offsetof(struct ubifs_mst_node, hmac);
+
+ /*
+ * Do not compare the common node header since the sequence number and
+ * hence the CRC are different.
+ */
+ ret = memcmp(m1 + UBIFS_CH_SZ, m2 + UBIFS_CH_SZ,
+ hmac_offs - UBIFS_CH_SZ);
+ if (ret)
+ return ret;
+
+ /*
+ * Do not compare the embedded HMAC aswell which also must be different
+ * due to the different common node header.
+ */
+ behind = hmac_offs + UBIFS_MAX_HMAC_LEN;
+
+ if (UBIFS_MST_NODE_SZ > behind)
+ return memcmp(m1 + behind, m2 + behind, UBIFS_MST_NODE_SZ - behind);
+
+ return 0;
+}
+
+/* mst_node_check_hash - Check hash of a master node
+ * @c: UBIFS file-system description object
+ * @mst: The master node
+ * @expected: The expected hash of the master node
+ *
+ * This checks the hash of a master node against a given expected hash.
+ * Note that we have two master nodes on a UBIFS image which have different
+ * sequence numbers and consequently different CRCs. To be able to match
+ * both master nodes we exclude the common node header containing the sequence
+ * number and CRC from the hash.
+ *
+ * Returns 0 if the hashes are equal, a negative error code otherwise.
+ */
+static int mst_node_check_hash(const struct ubifs_info *c,
+ const struct ubifs_mst_node *mst,
+ const u8 *expected)
+{
+ u8 calc[UBIFS_MAX_HASH_LEN];
+ const void *node = mst;
+
+ crypto_shash_tfm_digest(c->hash_tfm, node + sizeof(struct ubifs_ch),
+ UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch),
+ calc);
+
+ if (ubifs_check_hash(c, expected, calc))
+ return -EPERM;
+
+ return 0;
+}
/**
* scan_for_master - search the valid master node.
@@ -37,7 +91,7 @@
{
struct ubifs_scan_leb *sleb;
struct ubifs_scan_node *snod;
- int lnum, offs = 0, nodes_cnt;
+ int lnum, offs = 0, nodes_cnt, err;
lnum = UBIFS_MST_LNUM;
@@ -69,12 +123,31 @@
goto out_dump;
if (snod->offs != offs)
goto out;
- if (memcmp((void *)c->mst_node + UBIFS_CH_SZ,
- (void *)snod->node + UBIFS_CH_SZ,
- UBIFS_MST_NODE_SZ - UBIFS_CH_SZ))
+ if (ubifs_compare_master_node(c, c->mst_node, snod->node))
goto out;
+
c->mst_offs = offs;
ubifs_scan_destroy(sleb);
+
+ if (!ubifs_authenticated(c))
+ return 0;
+
+ if (ubifs_hmac_zero(c, c->mst_node->hmac)) {
+ err = mst_node_check_hash(c, c->mst_node,
+ c->sup_node->hash_mst);
+ if (err)
+ ubifs_err(c, "Failed to verify master node hash");
+ } else {
+ err = ubifs_node_verify_hmac(c, c->mst_node,
+ sizeof(struct ubifs_mst_node),
+ offsetof(struct ubifs_mst_node, hmac));
+ if (err)
+ ubifs_err(c, "Failed to verify master node HMAC");
+ }
+
+ if (err)
+ return -EPERM;
+
return 0;
out:
@@ -305,6 +378,8 @@
c->lst.total_dead = le64_to_cpu(c->mst_node->total_dead);
c->lst.total_dark = le64_to_cpu(c->mst_node->total_dark);
+ ubifs_copy_hash(c, c->mst_node->hash_root_idx, c->zroot.hash);
+
c->calc_idx_sz = c->bi.old_idx_sz;
if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS))
@@ -378,7 +453,9 @@
c->mst_offs = offs;
c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
- err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
+ ubifs_copy_hash(c, c->zroot.hash, c->mst_node->hash_root_idx);
+ err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs,
+ offsetof(struct ubifs_mst_node, hmac));
if (err)
return err;
@@ -389,7 +466,8 @@
if (err)
return err;
}
- err = ubifs_write_node(c, c->mst_node, len, lnum, offs);
+ err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs,
+ offsetof(struct ubifs_mst_node, hmac));
return err;
}
--
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