security: Create file_truncate hook from path_truncate hook

Like path_truncate, the file_truncate hook also restricts file
truncation, but is called in the cases where truncation is attempted
on an already-opened file.

This is required in a subsequent commit to handle ftruncate()
operations differently to truncate() operations.

Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20221018182216.301684-2-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
This commit is contained in:
Günther Noack 2022-10-18 20:22:06 +02:00 committed by Mickaël Salaün
parent 9abf2313ad
commit 3350607dc5
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8 changed files with 42 additions and 3 deletions

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@ -188,7 +188,7 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
if (IS_APPEND(file_inode(f.file)))
goto out_putf;
sb_start_write(inode->i_sb);
error = security_path_truncate(&f.file->f_path);
error = security_file_truncate(f.file);
if (!error)
error = do_truncate(file_mnt_user_ns(f.file), dentry, length,
ATTR_MTIME | ATTR_CTIME, f.file);