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pstore: inode: Convert mutex usage to guard(mutex)

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Replace open-coded mutex handling with cleanup.h guard(mutex) and
scoped_guard(mutex, ...).

Cc: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc:  <linux-hardening@vger.kernel.org>
Link: https://lore.kernel.org/r/20231205182622.1329923-2-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2023-12-05 10:26:15 -08:00
parent 6ba6ee8a59
commit e2eeddefb0
1 changed files with 30 additions and 44 deletions
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74
fs/pstore/inode.c
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@ -180,25 +180,21 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
{
struct pstore_private *p = d_inode(dentry)->i_private;
struct pstore_record *record = p->record;
int rc = 0;
if (!record->psi->erase)
return -EPERM;
/* Make sure we can't race while removing this file. */
mutex_lock(&records_list_lock);
if (!list_empty(&p->list))
list_del_init(&p->list);
else
rc = -ENOENT;
p->dentry = NULL;
mutex_unlock(&records_list_lock);
if (rc)
return rc;
scoped_guard(mutex, &records_list_lock) {
if (!list_empty(&p->list))
list_del_init(&p->list);
else
return -ENOENT;
p->dentry = NULL;
}
mutex_lock(&record->psi->read_mutex);
record->psi->erase(record);
mutex_unlock(&record->psi->read_mutex);
scoped_guard(mutex, &record->psi->read_mutex)
record->psi->erase(record);
return simple_unlink(dir, dentry);
}
@ -290,19 +286,16 @@ static struct dentry *psinfo_lock_root(void)
{
struct dentry *root;
mutex_lock(&pstore_sb_lock);
guard(mutex)(&pstore_sb_lock);
/*
* Having no backend is fine -- no records appear.
* Not being mounted is fine -- nothing to do.
*/
if (!psinfo || !pstore_sb) {
mutex_unlock(&pstore_sb_lock);
if (!psinfo || !pstore_sb)
return NULL;
}
root = pstore_sb->s_root;
inode_lock(d_inode(root));
mutex_unlock(&pstore_sb_lock);
return root;
}
@ -317,19 +310,19 @@ int pstore_put_backend_records(struct pstore_info *psi)
if (!root)
return 0;
mutex_lock(&records_list_lock);
list_for_each_entry_safe(pos, tmp, &records_list, list) {
if (pos->record->psi == psi) {
list_del_init(&pos->list);
rc = simple_unlink(d_inode(root), pos->dentry);
if (WARN_ON(rc))
break;
d_drop(pos->dentry);
dput(pos->dentry);
pos->dentry = NULL;
scoped_guard(mutex, &records_list_lock) {
list_for_each_entry_safe(pos, tmp, &records_list, list) {
if (pos->record->psi == psi) {
list_del_init(&pos->list);
rc = simple_unlink(d_inode(root), pos->dentry);
if (WARN_ON(rc))
break;
d_drop(pos->dentry);
dput(pos->dentry);
pos->dentry = NULL;
}
}
}
mutex_unlock(&records_list_lock);
inode_unlock(d_inode(root));
@ -353,20 +346,20 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
if (WARN_ON(!inode_is_locked(d_inode(root))))
return -EINVAL;
rc = -EEXIST;
guard(mutex)(&records_list_lock);
/* Skip records that are already present in the filesystem. */
mutex_lock(&records_list_lock);
list_for_each_entry(pos, &records_list, list) {
if (pos->record->type == record->type &&
pos->record->id == record->id &&
pos->record->psi == record->psi)
goto fail;
return -EEXIST;
}
rc = -ENOMEM;
inode = pstore_get_inode(root->d_sb);
if (!inode)
goto fail;
return -ENOMEM;
inode->i_mode = S_IFREG | 0444;
inode->i_fop = &pstore_file_operations;
scnprintf(name, sizeof(name), "%s-%s-%llu%s",
@ -394,7 +387,6 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
d_add(dentry, inode);
list_add(&private->list, &records_list);
mutex_unlock(&records_list_lock);
return 0;
@ -402,8 +394,6 @@ fail_private:
free_pstore_private(private);
fail_inode:
iput(inode);
fail:
mutex_unlock(&records_list_lock);
return rc;
}
@ -449,9 +439,8 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
if (!sb->s_root)
return -ENOMEM;
mutex_lock(&pstore_sb_lock);
pstore_sb = sb;
mutex_unlock(&pstore_sb_lock);
scoped_guard(mutex, &pstore_sb_lock)
pstore_sb = sb;
pstore_get_records(0);
@ -466,17 +455,14 @@ static struct dentry *pstore_mount(struct file_system_type *fs_type,
static void pstore_kill_sb(struct super_block *sb)
{
mutex_lock(&pstore_sb_lock);
guard(mutex)(&pstore_sb_lock);
WARN_ON(pstore_sb && pstore_sb != sb);
kill_litter_super(sb);
pstore_sb = NULL;
mutex_lock(&records_list_lock);
guard(mutex)(&records_list_lock);
INIT_LIST_HEAD(&records_list);
mutex_unlock(&records_list_lock);
mutex_unlock(&pstore_sb_lock);
}
static struct file_system_type pstore_fs_type = {