https://github.com/torvalds/linux
Tip revision: f40ddce88593482919761f74910f42f4b84c004b authored by Linus Torvalds on 14 February 2021, 22:32:24 UTC
Linux 5.11
Linux 5.11
Tip revision: f40ddce
master.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
*
* Authors: Artem Bityutskiy (Битюцкий Артём)
* Adrian Hunter
*/
/* 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.
* @c: UBIFS file-system description object
*
* This function scans the master node LEBs and search for the latest master
* node. Returns zero in case of success, %-EUCLEAN if there master area is
* corrupted and requires recovery, and a negative error code in case of
* failure.
*/
static int scan_for_master(struct ubifs_info *c)
{
struct ubifs_scan_leb *sleb;
struct ubifs_scan_node *snod;
int lnum, offs = 0, nodes_cnt, err;
lnum = UBIFS_MST_LNUM;
sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
if (IS_ERR(sleb))
return PTR_ERR(sleb);
nodes_cnt = sleb->nodes_cnt;
if (nodes_cnt > 0) {
snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
list);
if (snod->type != UBIFS_MST_NODE)
goto out_dump;
memcpy(c->mst_node, snod->node, snod->len);
offs = snod->offs;
}
ubifs_scan_destroy(sleb);
lnum += 1;
sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
if (IS_ERR(sleb))
return PTR_ERR(sleb);
if (sleb->nodes_cnt != nodes_cnt)
goto out;
if (!sleb->nodes_cnt)
goto out;
snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list);
if (snod->type != UBIFS_MST_NODE)
goto out_dump;
if (snod->offs != offs)
goto out;
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:
ubifs_scan_destroy(sleb);
return -EUCLEAN;
out_dump:
ubifs_err(c, "unexpected node type %d master LEB %d:%d",
snod->type, lnum, snod->offs);
ubifs_scan_destroy(sleb);
return -EINVAL;
}
/**
* validate_master - validate master node.
* @c: UBIFS file-system description object
*
* This function validates data which was read from master node. Returns zero
* if the data is all right and %-EINVAL if not.
*/
static int validate_master(const struct ubifs_info *c)
{
long long main_sz;
int err;
if (c->max_sqnum >= SQNUM_WATERMARK) {
err = 1;
goto out;
}
if (c->cmt_no >= c->max_sqnum) {
err = 2;
goto out;
}
if (c->highest_inum >= INUM_WATERMARK) {
err = 3;
goto out;
}
if (c->lhead_lnum < UBIFS_LOG_LNUM ||
c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs ||
c->lhead_offs < 0 || c->lhead_offs >= c->leb_size ||
c->lhead_offs & (c->min_io_size - 1)) {
err = 4;
goto out;
}
if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first ||
c->zroot.offs >= c->leb_size || c->zroot.offs & 7) {
err = 5;
goto out;
}
if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len ||
c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) {
err = 6;
goto out;
}
if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) {
err = 7;
goto out;
}
if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first ||
c->ihead_offs % c->min_io_size || c->ihead_offs < 0 ||
c->ihead_offs > c->leb_size || c->ihead_offs & 7) {
err = 8;
goto out;
}
main_sz = (long long)c->main_lebs * c->leb_size;
if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) {
err = 9;
goto out;
}
if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last ||
c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) {
err = 10;
goto out;
}
if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last ||
c->nhead_offs < 0 || c->nhead_offs % c->min_io_size ||
c->nhead_offs > c->leb_size) {
err = 11;
goto out;
}
if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last ||
c->ltab_offs < 0 ||
c->ltab_offs + c->ltab_sz > c->leb_size) {
err = 12;
goto out;
}
if (c->big_lpt && (c->lsave_lnum < c->lpt_first ||
c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 ||
c->lsave_offs + c->lsave_sz > c->leb_size)) {
err = 13;
goto out;
}
if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) {
err = 14;
goto out;
}
if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) {
err = 15;
goto out;
}
if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) {
err = 16;
goto out;
}
if (c->lst.total_free < 0 || c->lst.total_free > main_sz ||
c->lst.total_free & 7) {
err = 17;
goto out;
}
if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) {
err = 18;
goto out;
}
if (c->lst.total_used < 0 || (c->lst.total_used & 7)) {
err = 19;
goto out;
}
if (c->lst.total_free + c->lst.total_dirty +
c->lst.total_used > main_sz) {
err = 20;
goto out;
}
if (c->lst.total_dead + c->lst.total_dark +
c->lst.total_used + c->bi.old_idx_sz > main_sz) {
err = 21;
goto out;
}
if (c->lst.total_dead < 0 ||
c->lst.total_dead > c->lst.total_free + c->lst.total_dirty ||
c->lst.total_dead & 7) {
err = 22;
goto out;
}
if (c->lst.total_dark < 0 ||
c->lst.total_dark > c->lst.total_free + c->lst.total_dirty ||
c->lst.total_dark & 7) {
err = 23;
goto out;
}
return 0;
out:
ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err);
ubifs_dump_node(c, c->mst_node, c->mst_node_alsz);
return -EINVAL;
}
/**
* ubifs_read_master - read master node.
* @c: UBIFS file-system description object
*
* This function finds and reads the master node during file-system mount. If
* the flash is empty, it creates default master node as well. Returns zero in
* case of success and a negative error code in case of failure.
*/
int ubifs_read_master(struct ubifs_info *c)
{
int err, old_leb_cnt;
c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL);
if (!c->mst_node)
return -ENOMEM;
err = scan_for_master(c);
if (err) {
if (err == -EUCLEAN)
err = ubifs_recover_master_node(c);
if (err)
/*
* Note, we do not free 'c->mst_node' here because the
* unmount routine will take care of this.
*/
return err;
}
/* Make sure that the recovery flag is clear */
c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY);
c->max_sqnum = le64_to_cpu(c->mst_node->ch.sqnum);
c->highest_inum = le64_to_cpu(c->mst_node->highest_inum);
c->cmt_no = le64_to_cpu(c->mst_node->cmt_no);
c->zroot.lnum = le32_to_cpu(c->mst_node->root_lnum);
c->zroot.offs = le32_to_cpu(c->mst_node->root_offs);
c->zroot.len = le32_to_cpu(c->mst_node->root_len);
c->lhead_lnum = le32_to_cpu(c->mst_node->log_lnum);
c->gc_lnum = le32_to_cpu(c->mst_node->gc_lnum);
c->ihead_lnum = le32_to_cpu(c->mst_node->ihead_lnum);
c->ihead_offs = le32_to_cpu(c->mst_node->ihead_offs);
c->bi.old_idx_sz = le64_to_cpu(c->mst_node->index_size);
c->lpt_lnum = le32_to_cpu(c->mst_node->lpt_lnum);
c->lpt_offs = le32_to_cpu(c->mst_node->lpt_offs);
c->nhead_lnum = le32_to_cpu(c->mst_node->nhead_lnum);
c->nhead_offs = le32_to_cpu(c->mst_node->nhead_offs);
c->ltab_lnum = le32_to_cpu(c->mst_node->ltab_lnum);
c->ltab_offs = le32_to_cpu(c->mst_node->ltab_offs);
c->lsave_lnum = le32_to_cpu(c->mst_node->lsave_lnum);
c->lsave_offs = le32_to_cpu(c->mst_node->lsave_offs);
c->lscan_lnum = le32_to_cpu(c->mst_node->lscan_lnum);
c->lst.empty_lebs = le32_to_cpu(c->mst_node->empty_lebs);
c->lst.idx_lebs = le32_to_cpu(c->mst_node->idx_lebs);
old_leb_cnt = le32_to_cpu(c->mst_node->leb_cnt);
c->lst.total_free = le64_to_cpu(c->mst_node->total_free);
c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty);
c->lst.total_used = le64_to_cpu(c->mst_node->total_used);
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))
c->no_orphs = 1;
if (old_leb_cnt != c->leb_cnt) {
/* The file system has been resized */
int growth = c->leb_cnt - old_leb_cnt;
if (c->leb_cnt < old_leb_cnt ||
c->leb_cnt < UBIFS_MIN_LEB_CNT) {
ubifs_err(c, "bad leb_cnt on master node");
ubifs_dump_node(c, c->mst_node, c->mst_node_alsz);
return -EINVAL;
}
dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs",
old_leb_cnt, c->leb_cnt);
c->lst.empty_lebs += growth;
c->lst.total_free += growth * (long long)c->leb_size;
c->lst.total_dark += growth * (long long)c->dark_wm;
/*
* Reflect changes back onto the master node. N.B. the master
* node gets written immediately whenever mounting (or
* remounting) in read-write mode, so we do not need to write it
* here.
*/
c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt);
c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs);
c->mst_node->total_free = cpu_to_le64(c->lst.total_free);
c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark);
}
err = validate_master(c);
if (err)
return err;
err = dbg_old_index_check_init(c, &c->zroot);
return err;
}
/**
* ubifs_write_master - write master node.
* @c: UBIFS file-system description object
*
* This function writes the master node. Returns zero in case of success and a
* negative error code in case of failure. The master node is written twice to
* enable recovery.
*/
int ubifs_write_master(struct ubifs_info *c)
{
int err, lnum, offs, len;
ubifs_assert(c, !c->ro_media && !c->ro_mount);
if (c->ro_error)
return -EROFS;
lnum = UBIFS_MST_LNUM;
offs = c->mst_offs + c->mst_node_alsz;
len = UBIFS_MST_NODE_SZ;
if (offs + UBIFS_MST_NODE_SZ > c->leb_size) {
err = ubifs_leb_unmap(c, lnum);
if (err)
return err;
offs = 0;
}
c->mst_offs = offs;
c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
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;
lnum += 1;
if (offs == 0) {
err = ubifs_leb_unmap(c, lnum);
if (err)
return err;
}
err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs,
offsetof(struct ubifs_mst_node, hmac));
return err;
}