Revision 5f56a74cc0a6d9b9f8ba89cea29cd7c4774cb2b1 authored by Ard Biesheuvel on 20 September 2022, 15:08:23 UTC, committed by Ard Biesheuvel on 22 September 2022, 08:15:44 UTC
We currently check the MokSBState variable to decide whether we should treat UEFI secure boot as being disabled, even if the firmware thinks otherwise. This is used by shim to indicate that it is not checking signatures on boot images. In the kernel, we use this to relax lockdown policies. However, in cases where shim is not even being used, we don't want this variable to interfere with lockdown, given that the variable may be non-volatile and therefore persist across a reboot. This means setting it once will persistently disable lockdown checks on a given system. So switch to the mirrored version of this variable, called MokSBStateRT, which is supposed to be volatile, and this is something we can check. Cc: <stable@vger.kernel.org> # v4.19+ Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Reviewed-by: Peter Jones <pjones@redhat.com>
1 parent 63bf28c
brec.c
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/hfs/brec.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
* Handle individual btree records
*/
#include "btree.h"
static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd);
static int hfs_brec_update_parent(struct hfs_find_data *fd);
static int hfs_btree_inc_height(struct hfs_btree *tree);
/* Get the length and offset of the given record in the given node */
u16 hfs_brec_lenoff(struct hfs_bnode *node, u16 rec, u16 *off)
{
__be16 retval[2];
u16 dataoff;
dataoff = node->tree->node_size - (rec + 2) * 2;
hfs_bnode_read(node, retval, dataoff, 4);
*off = be16_to_cpu(retval[1]);
return be16_to_cpu(retval[0]) - *off;
}
/* Get the length of the key from a keyed record */
u16 hfs_brec_keylen(struct hfs_bnode *node, u16 rec)
{
u16 retval, recoff;
if (node->type != HFS_NODE_INDEX && node->type != HFS_NODE_LEAF)
return 0;
if ((node->type == HFS_NODE_INDEX) &&
!(node->tree->attributes & HFS_TREE_VARIDXKEYS)) {
if (node->tree->attributes & HFS_TREE_BIGKEYS)
retval = node->tree->max_key_len + 2;
else
retval = node->tree->max_key_len + 1;
} else {
recoff = hfs_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
if (!recoff)
return 0;
if (node->tree->attributes & HFS_TREE_BIGKEYS) {
retval = hfs_bnode_read_u16(node, recoff) + 2;
if (retval > node->tree->max_key_len + 2) {
pr_err("keylen %d too large\n", retval);
retval = 0;
}
} else {
retval = (hfs_bnode_read_u8(node, recoff) | 1) + 1;
if (retval > node->tree->max_key_len + 1) {
pr_err("keylen %d too large\n", retval);
retval = 0;
}
}
}
return retval;
}
int hfs_brec_insert(struct hfs_find_data *fd, void *entry, int entry_len)
{
struct hfs_btree *tree;
struct hfs_bnode *node, *new_node;
int size, key_len, rec;
int data_off, end_off;
int idx_rec_off, data_rec_off, end_rec_off;
__be32 cnid;
tree = fd->tree;
if (!fd->bnode) {
if (!tree->root)
hfs_btree_inc_height(tree);
node = hfs_bnode_find(tree, tree->leaf_head);
if (IS_ERR(node))
return PTR_ERR(node);
fd->bnode = node;
fd->record = -1;
}
new_node = NULL;
key_len = (fd->search_key->key_len | 1) + 1;
again:
/* new record idx and complete record size */
rec = fd->record + 1;
size = key_len + entry_len;
node = fd->bnode;
hfs_bnode_dump(node);
/* get last offset */
end_rec_off = tree->node_size - (node->num_recs + 1) * 2;
end_off = hfs_bnode_read_u16(node, end_rec_off);
end_rec_off -= 2;
hfs_dbg(BNODE_MOD, "insert_rec: %d, %d, %d, %d\n",
rec, size, end_off, end_rec_off);
if (size > end_rec_off - end_off) {
if (new_node)
panic("not enough room!\n");
new_node = hfs_bnode_split(fd);
if (IS_ERR(new_node))
return PTR_ERR(new_node);
goto again;
}
if (node->type == HFS_NODE_LEAF) {
tree->leaf_count++;
mark_inode_dirty(tree->inode);
}
node->num_recs++;
/* write new last offset */
hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
hfs_bnode_write_u16(node, end_rec_off, end_off + size);
data_off = end_off;
data_rec_off = end_rec_off + 2;
idx_rec_off = tree->node_size - (rec + 1) * 2;
if (idx_rec_off == data_rec_off)
goto skip;
/* move all following entries */
do {
data_off = hfs_bnode_read_u16(node, data_rec_off + 2);
hfs_bnode_write_u16(node, data_rec_off, data_off + size);
data_rec_off += 2;
} while (data_rec_off < idx_rec_off);
/* move data away */
hfs_bnode_move(node, data_off + size, data_off,
end_off - data_off);
skip:
hfs_bnode_write(node, fd->search_key, data_off, key_len);
hfs_bnode_write(node, entry, data_off + key_len, entry_len);
hfs_bnode_dump(node);
/*
* update parent key if we inserted a key
* at the start of the node and it is not the new node
*/
if (!rec && new_node != node) {
hfs_bnode_read_key(node, fd->search_key, data_off + size);
hfs_brec_update_parent(fd);
}
if (new_node) {
hfs_bnode_put(fd->bnode);
if (!new_node->parent) {
hfs_btree_inc_height(tree);
new_node->parent = tree->root;
}
fd->bnode = hfs_bnode_find(tree, new_node->parent);
/* create index data entry */
cnid = cpu_to_be32(new_node->this);
entry = &cnid;
entry_len = sizeof(cnid);
/* get index key */
hfs_bnode_read_key(new_node, fd->search_key, 14);
__hfs_brec_find(fd->bnode, fd);
hfs_bnode_put(new_node);
new_node = NULL;
if (tree->attributes & HFS_TREE_VARIDXKEYS)
key_len = fd->search_key->key_len + 1;
else {
fd->search_key->key_len = tree->max_key_len;
key_len = tree->max_key_len + 1;
}
goto again;
}
return 0;
}
int hfs_brec_remove(struct hfs_find_data *fd)
{
struct hfs_btree *tree;
struct hfs_bnode *node, *parent;
int end_off, rec_off, data_off, size;
tree = fd->tree;
node = fd->bnode;
again:
rec_off = tree->node_size - (fd->record + 2) * 2;
end_off = tree->node_size - (node->num_recs + 1) * 2;
if (node->type == HFS_NODE_LEAF) {
tree->leaf_count--;
mark_inode_dirty(tree->inode);
}
hfs_bnode_dump(node);
hfs_dbg(BNODE_MOD, "remove_rec: %d, %d\n",
fd->record, fd->keylength + fd->entrylength);
if (!--node->num_recs) {
hfs_bnode_unlink(node);
if (!node->parent)
return 0;
parent = hfs_bnode_find(tree, node->parent);
if (IS_ERR(parent))
return PTR_ERR(parent);
hfs_bnode_put(node);
node = fd->bnode = parent;
__hfs_brec_find(node, fd);
goto again;
}
hfs_bnode_write_u16(node, offsetof(struct hfs_bnode_desc, num_recs), node->num_recs);
if (rec_off == end_off)
goto skip;
size = fd->keylength + fd->entrylength;
do {
data_off = hfs_bnode_read_u16(node, rec_off);
hfs_bnode_write_u16(node, rec_off + 2, data_off - size);
rec_off -= 2;
} while (rec_off >= end_off);
/* fill hole */
hfs_bnode_move(node, fd->keyoffset, fd->keyoffset + size,
data_off - fd->keyoffset - size);
skip:
hfs_bnode_dump(node);
if (!fd->record)
hfs_brec_update_parent(fd);
return 0;
}
static struct hfs_bnode *hfs_bnode_split(struct hfs_find_data *fd)
{
struct hfs_btree *tree;
struct hfs_bnode *node, *new_node, *next_node;
struct hfs_bnode_desc node_desc;
int num_recs, new_rec_off, new_off, old_rec_off;
int data_start, data_end, size;
tree = fd->tree;
node = fd->bnode;
new_node = hfs_bmap_alloc(tree);
if (IS_ERR(new_node))
return new_node;
hfs_bnode_get(node);
hfs_dbg(BNODE_MOD, "split_nodes: %d - %d - %d\n",
node->this, new_node->this, node->next);
new_node->next = node->next;
new_node->prev = node->this;
new_node->parent = node->parent;
new_node->type = node->type;
new_node->height = node->height;
if (node->next)
next_node = hfs_bnode_find(tree, node->next);
else
next_node = NULL;
if (IS_ERR(next_node)) {
hfs_bnode_put(node);
hfs_bnode_put(new_node);
return next_node;
}
size = tree->node_size / 2 - node->num_recs * 2 - 14;
old_rec_off = tree->node_size - 4;
num_recs = 1;
for (;;) {
data_start = hfs_bnode_read_u16(node, old_rec_off);
if (data_start > size)
break;
old_rec_off -= 2;
if (++num_recs < node->num_recs)
continue;
/* panic? */
hfs_bnode_put(node);
hfs_bnode_put(new_node);
if (next_node)
hfs_bnode_put(next_node);
return ERR_PTR(-ENOSPC);
}
if (fd->record + 1 < num_recs) {
/* new record is in the lower half,
* so leave some more space there
*/
old_rec_off += 2;
num_recs--;
data_start = hfs_bnode_read_u16(node, old_rec_off);
} else {
hfs_bnode_put(node);
hfs_bnode_get(new_node);
fd->bnode = new_node;
fd->record -= num_recs;
fd->keyoffset -= data_start - 14;
fd->entryoffset -= data_start - 14;
}
new_node->num_recs = node->num_recs - num_recs;
node->num_recs = num_recs;
new_rec_off = tree->node_size - 2;
new_off = 14;
size = data_start - new_off;
num_recs = new_node->num_recs;
data_end = data_start;
while (num_recs) {
hfs_bnode_write_u16(new_node, new_rec_off, new_off);
old_rec_off -= 2;
new_rec_off -= 2;
data_end = hfs_bnode_read_u16(node, old_rec_off);
new_off = data_end - size;
num_recs--;
}
hfs_bnode_write_u16(new_node, new_rec_off, new_off);
hfs_bnode_copy(new_node, 14, node, data_start, data_end - data_start);
/* update new bnode header */
node_desc.next = cpu_to_be32(new_node->next);
node_desc.prev = cpu_to_be32(new_node->prev);
node_desc.type = new_node->type;
node_desc.height = new_node->height;
node_desc.num_recs = cpu_to_be16(new_node->num_recs);
node_desc.reserved = 0;
hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
/* update previous bnode header */
node->next = new_node->this;
hfs_bnode_read(node, &node_desc, 0, sizeof(node_desc));
node_desc.next = cpu_to_be32(node->next);
node_desc.num_recs = cpu_to_be16(node->num_recs);
hfs_bnode_write(node, &node_desc, 0, sizeof(node_desc));
/* update next bnode header */
if (next_node) {
next_node->prev = new_node->this;
hfs_bnode_read(next_node, &node_desc, 0, sizeof(node_desc));
node_desc.prev = cpu_to_be32(next_node->prev);
hfs_bnode_write(next_node, &node_desc, 0, sizeof(node_desc));
hfs_bnode_put(next_node);
} else if (node->this == tree->leaf_tail) {
/* if there is no next node, this might be the new tail */
tree->leaf_tail = new_node->this;
mark_inode_dirty(tree->inode);
}
hfs_bnode_dump(node);
hfs_bnode_dump(new_node);
hfs_bnode_put(node);
return new_node;
}
static int hfs_brec_update_parent(struct hfs_find_data *fd)
{
struct hfs_btree *tree;
struct hfs_bnode *node, *new_node, *parent;
int newkeylen, diff;
int rec, rec_off, end_rec_off;
int start_off, end_off;
tree = fd->tree;
node = fd->bnode;
new_node = NULL;
if (!node->parent)
return 0;
again:
parent = hfs_bnode_find(tree, node->parent);
if (IS_ERR(parent))
return PTR_ERR(parent);
__hfs_brec_find(parent, fd);
if (fd->record < 0)
return -ENOENT;
hfs_bnode_dump(parent);
rec = fd->record;
/* size difference between old and new key */
if (tree->attributes & HFS_TREE_VARIDXKEYS)
newkeylen = (hfs_bnode_read_u8(node, 14) | 1) + 1;
else
fd->keylength = newkeylen = tree->max_key_len + 1;
hfs_dbg(BNODE_MOD, "update_rec: %d, %d, %d\n",
rec, fd->keylength, newkeylen);
rec_off = tree->node_size - (rec + 2) * 2;
end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
diff = newkeylen - fd->keylength;
if (!diff)
goto skip;
if (diff > 0) {
end_off = hfs_bnode_read_u16(parent, end_rec_off);
if (end_rec_off - end_off < diff) {
printk(KERN_DEBUG "splitting index node...\n");
fd->bnode = parent;
new_node = hfs_bnode_split(fd);
if (IS_ERR(new_node))
return PTR_ERR(new_node);
parent = fd->bnode;
rec = fd->record;
rec_off = tree->node_size - (rec + 2) * 2;
end_rec_off = tree->node_size - (parent->num_recs + 1) * 2;
}
}
end_off = start_off = hfs_bnode_read_u16(parent, rec_off);
hfs_bnode_write_u16(parent, rec_off, start_off + diff);
start_off -= 4; /* move previous cnid too */
while (rec_off > end_rec_off) {
rec_off -= 2;
end_off = hfs_bnode_read_u16(parent, rec_off);
hfs_bnode_write_u16(parent, rec_off, end_off + diff);
}
hfs_bnode_move(parent, start_off + diff, start_off,
end_off - start_off);
skip:
hfs_bnode_copy(parent, fd->keyoffset, node, 14, newkeylen);
if (!(tree->attributes & HFS_TREE_VARIDXKEYS))
hfs_bnode_write_u8(parent, fd->keyoffset, newkeylen - 1);
hfs_bnode_dump(parent);
hfs_bnode_put(node);
node = parent;
if (new_node) {
__be32 cnid;
if (!new_node->parent) {
hfs_btree_inc_height(tree);
new_node->parent = tree->root;
}
fd->bnode = hfs_bnode_find(tree, new_node->parent);
/* create index key and entry */
hfs_bnode_read_key(new_node, fd->search_key, 14);
cnid = cpu_to_be32(new_node->this);
__hfs_brec_find(fd->bnode, fd);
hfs_brec_insert(fd, &cnid, sizeof(cnid));
hfs_bnode_put(fd->bnode);
hfs_bnode_put(new_node);
if (!rec) {
if (new_node == node)
goto out;
/* restore search_key */
hfs_bnode_read_key(node, fd->search_key, 14);
}
new_node = NULL;
}
if (!rec && node->parent)
goto again;
out:
fd->bnode = node;
return 0;
}
static int hfs_btree_inc_height(struct hfs_btree *tree)
{
struct hfs_bnode *node, *new_node;
struct hfs_bnode_desc node_desc;
int key_size, rec;
__be32 cnid;
node = NULL;
if (tree->root) {
node = hfs_bnode_find(tree, tree->root);
if (IS_ERR(node))
return PTR_ERR(node);
}
new_node = hfs_bmap_alloc(tree);
if (IS_ERR(new_node)) {
hfs_bnode_put(node);
return PTR_ERR(new_node);
}
tree->root = new_node->this;
if (!tree->depth) {
tree->leaf_head = tree->leaf_tail = new_node->this;
new_node->type = HFS_NODE_LEAF;
new_node->num_recs = 0;
} else {
new_node->type = HFS_NODE_INDEX;
new_node->num_recs = 1;
}
new_node->parent = 0;
new_node->next = 0;
new_node->prev = 0;
new_node->height = ++tree->depth;
node_desc.next = cpu_to_be32(new_node->next);
node_desc.prev = cpu_to_be32(new_node->prev);
node_desc.type = new_node->type;
node_desc.height = new_node->height;
node_desc.num_recs = cpu_to_be16(new_node->num_recs);
node_desc.reserved = 0;
hfs_bnode_write(new_node, &node_desc, 0, sizeof(node_desc));
rec = tree->node_size - 2;
hfs_bnode_write_u16(new_node, rec, 14);
if (node) {
/* insert old root idx into new root */
node->parent = tree->root;
if (node->type == HFS_NODE_LEAF ||
tree->attributes & HFS_TREE_VARIDXKEYS)
key_size = hfs_bnode_read_u8(node, 14) + 1;
else
key_size = tree->max_key_len + 1;
hfs_bnode_copy(new_node, 14, node, 14, key_size);
if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
key_size = tree->max_key_len + 1;
hfs_bnode_write_u8(new_node, 14, tree->max_key_len);
}
key_size = (key_size + 1) & -2;
cnid = cpu_to_be32(node->this);
hfs_bnode_write(new_node, &cnid, 14 + key_size, 4);
rec -= 2;
hfs_bnode_write_u16(new_node, rec, 14 + key_size + 4);
hfs_bnode_put(node);
}
hfs_bnode_put(new_node);
mark_inode_dirty(tree->inode);
return 0;
}
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