Re: [GIT PULL] execve updates for v6.13-rc1 (take 2)
From: Linus Torvalds
Date: Thu Nov 28 2024 - 23:44:39 EST
On Thu, 28 Nov 2024 at 19:34, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> Just one thing - IMO we want to use the relative pathname when it's
> not empty. Even in execveat()
Oh, absolutely agreed.
Good catch, because yes, I messed that part up in my suggested patch at
https://lore.kernel.org/all/CAHk-=wjF_09Z6vu7f8UAbQVDDoHnd-j391YpUxmBPLD=SKbKtQ@xxxxxxxxxxxxxx/
which did this dentry name thing for anything that used a base fd, but
yes, as you say, it should only do it when there is no name at all.
So instead of basing it (incorrectly) on that existing
if (fd == AT_FDCWD || filename->name[0] == '/') {
test, the logic should probably look something like
if (!filename->name[0]) {
rcu_read_lock();
strscpy(bprm->comm,
smp_load_acquire(&file->f_path.dentry->d_name.name));
rcu_read_unlock();
} else
strscpy(bprm->comm, kbasename(filename->name));
and it probably wouldn't be a bad idea to separate this out to be a
helper function that just does this one thing.
Linus