From: Al Viro <viro@zeniv.linux.org.uk>
To: linux-security-module@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Subject: [WTF][landlock] d_is_negative(fd_file(f)->f_path.dentry) ???
Date: Thu, 24 Apr 2025 23:00:11 +0100 [thread overview]
Message-ID: <20250424220011.GJ2023217@ZenIV> (raw)
static int get_path_from_fd(const s32 fd, struct path *const path)
{
...
if ((fd_file(f)->f_op == &ruleset_fops) ||
(fd_file(f)->f_path.mnt->mnt_flags & MNT_INTERNAL) ||
(fd_file(f)->f_path.dentry->d_sb->s_flags & SB_NOUSER) ||
d_is_negative(fd_file(f)->f_path.dentry) ||
IS_PRIVATE(d_backing_inode(fd_file(f)->f_path.dentry)))
return -EBADFD;
Folks, could somebody explain how exactly can an opened file
come to have a _negative_ dentry? And if you have found a way for that
to happen, why didn't you report the arseloads of NULL pointer dereference
bugs that would expose, along with assorted memory corruptors, etc.?
Normally I would just quietly rip the bogus check out, but on
the off-chance that somebody _has_ found a bug that would cause that,
I would prefer to check with those who had added the check in the first
place.
next reply other threads:[~2025-04-24 22:00 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-24 22:00 Al Viro [this message]
2025-04-25 9:38 ` [WTF][landlock] d_is_negative(fd_file(f)->f_path.dentry) ??? Mickaël Salaün
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250424220011.GJ2023217@ZenIV \
--to=viro@zeniv.linux.org.uk \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox