pstore: inode: Convert mutex usage to guard(mutex)
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>
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@ -180,25 +180,21 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct pstore_private *p = d_inode(dentry)->i_private;
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struct pstore_record *record = p->record;
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int rc = 0;
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if (!record->psi->erase)
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return -EPERM;
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/* Make sure we can't race while removing this file. */
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mutex_lock(&records_list_lock);
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if (!list_empty(&p->list))
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list_del_init(&p->list);
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else
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rc = -ENOENT;
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p->dentry = NULL;
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mutex_unlock(&records_list_lock);
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if (rc)
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return rc;
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scoped_guard(mutex, &records_list_lock) {
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if (!list_empty(&p->list))
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list_del_init(&p->list);
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else
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return -ENOENT;
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p->dentry = NULL;
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}
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mutex_lock(&record->psi->read_mutex);
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record->psi->erase(record);
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mutex_unlock(&record->psi->read_mutex);
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scoped_guard(mutex, &record->psi->read_mutex)
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record->psi->erase(record);
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return simple_unlink(dir, dentry);
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}
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@ -290,19 +286,16 @@ static struct dentry *psinfo_lock_root(void)
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{
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struct dentry *root;
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mutex_lock(&pstore_sb_lock);
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guard(mutex)(&pstore_sb_lock);
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/*
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* Having no backend is fine -- no records appear.
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* Not being mounted is fine -- nothing to do.
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*/
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if (!psinfo || !pstore_sb) {
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mutex_unlock(&pstore_sb_lock);
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if (!psinfo || !pstore_sb)
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return NULL;
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}
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root = pstore_sb->s_root;
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inode_lock(d_inode(root));
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mutex_unlock(&pstore_sb_lock);
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return root;
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}
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@ -317,19 +310,19 @@ int pstore_put_backend_records(struct pstore_info *psi)
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if (!root)
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return 0;
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mutex_lock(&records_list_lock);
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list_for_each_entry_safe(pos, tmp, &records_list, list) {
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if (pos->record->psi == psi) {
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list_del_init(&pos->list);
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rc = simple_unlink(d_inode(root), pos->dentry);
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if (WARN_ON(rc))
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break;
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d_drop(pos->dentry);
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dput(pos->dentry);
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pos->dentry = NULL;
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scoped_guard(mutex, &records_list_lock) {
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list_for_each_entry_safe(pos, tmp, &records_list, list) {
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if (pos->record->psi == psi) {
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list_del_init(&pos->list);
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rc = simple_unlink(d_inode(root), pos->dentry);
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if (WARN_ON(rc))
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break;
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d_drop(pos->dentry);
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dput(pos->dentry);
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pos->dentry = NULL;
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}
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}
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}
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mutex_unlock(&records_list_lock);
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inode_unlock(d_inode(root));
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@ -353,20 +346,20 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
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if (WARN_ON(!inode_is_locked(d_inode(root))))
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return -EINVAL;
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rc = -EEXIST;
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guard(mutex)(&records_list_lock);
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/* Skip records that are already present in the filesystem. */
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mutex_lock(&records_list_lock);
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list_for_each_entry(pos, &records_list, list) {
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if (pos->record->type == record->type &&
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pos->record->id == record->id &&
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pos->record->psi == record->psi)
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goto fail;
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return -EEXIST;
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}
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rc = -ENOMEM;
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inode = pstore_get_inode(root->d_sb);
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if (!inode)
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goto fail;
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return -ENOMEM;
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inode->i_mode = S_IFREG | 0444;
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inode->i_fop = &pstore_file_operations;
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scnprintf(name, sizeof(name), "%s-%s-%llu%s",
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@ -394,7 +387,6 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
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d_add(dentry, inode);
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list_add(&private->list, &records_list);
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mutex_unlock(&records_list_lock);
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return 0;
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@ -402,8 +394,6 @@ fail_private:
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free_pstore_private(private);
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fail_inode:
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iput(inode);
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fail:
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mutex_unlock(&records_list_lock);
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return rc;
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}
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@ -449,9 +439,8 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
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if (!sb->s_root)
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return -ENOMEM;
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mutex_lock(&pstore_sb_lock);
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pstore_sb = sb;
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mutex_unlock(&pstore_sb_lock);
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scoped_guard(mutex, &pstore_sb_lock)
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pstore_sb = sb;
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pstore_get_records(0);
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@ -466,17 +455,14 @@ static struct dentry *pstore_mount(struct file_system_type *fs_type,
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static void pstore_kill_sb(struct super_block *sb)
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{
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mutex_lock(&pstore_sb_lock);
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guard(mutex)(&pstore_sb_lock);
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WARN_ON(pstore_sb && pstore_sb != sb);
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kill_litter_super(sb);
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pstore_sb = NULL;
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mutex_lock(&records_list_lock);
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guard(mutex)(&records_list_lock);
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INIT_LIST_HEAD(&records_list);
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mutex_unlock(&records_list_lock);
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mutex_unlock(&pstore_sb_lock);
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}
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static struct file_system_type pstore_fs_type = {
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