From: Al Viro <viro@zeniv.linux.org.uk>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-mtd@lists.infradead.org, linux-unionfs@vger.kernel.org,
Sarthak Kukreti <sarthakkukreti@chromium.org>,
Gao Xiang <gaoxiang25@huawei.com>
Subject: Re: [PATCH 1/5] fscrypt: clean up and improve dentry revalidation
Date: Sun, 17 Mar 2019 20:38:22 +0000 [thread overview]
Message-ID: <20190317203822.GH2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190317200444.5967-2-ebiggers@kernel.org>
On Sun, Mar 17, 2019 at 01:04:40PM -0700, Eric Biggers wrote:
> + /*
> + * Ciphertext name; valid if the directory's key is still unavailable.
> + *
> + * Note: since fscrypt forbids rename() on ciphertext names, it should
> + * be safe to access ->d_parent directly here.
No, it is not. Again, d_splice_alias() on buggered fs image picking a reference
to your subdirectory when doing a lookup elsewhere. It can relocate the
damn thing, without rename() being allowed for _anything_.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-unionfs@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org,
Sarthak Kukreti <sarthakkukreti@chromium.org>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 1/5] fscrypt: clean up and improve dentry revalidation
Date: Sun, 17 Mar 2019 20:38:22 +0000 [thread overview]
Message-ID: <20190317203822.GH2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190317200444.5967-2-ebiggers@kernel.org>
On Sun, Mar 17, 2019 at 01:04:40PM -0700, Eric Biggers wrote:
> + /*
> + * Ciphertext name; valid if the directory's key is still unavailable.
> + *
> + * Note: since fscrypt forbids rename() on ciphertext names, it should
> + * be safe to access ->d_parent directly here.
No, it is not. Again, d_splice_alias() on buggered fs image picking a reference
to your subdirectory when doing a lookup elsewhere. It can relocate the
damn thing, without rename() being allowed for _anything_.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Gao Xiang <gaoxiang25@huawei.com>,
linux-unionfs@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org,
Sarthak Kukreti <sarthakkukreti@chromium.org>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 1/5] fscrypt: clean up and improve dentry revalidation
Date: Sun, 17 Mar 2019 20:38:22 +0000 [thread overview]
Message-ID: <20190317203822.GH2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190317200444.5967-2-ebiggers@kernel.org>
On Sun, Mar 17, 2019 at 01:04:40PM -0700, Eric Biggers wrote:
> + /*
> + * Ciphertext name; valid if the directory's key is still unavailable.
> + *
> + * Note: since fscrypt forbids rename() on ciphertext names, it should
> + * be safe to access ->d_parent directly here.
No, it is not. Again, d_splice_alias() on buggered fs image picking a reference
to your subdirectory when doing a lookup elsewhere. It can relocate the
damn thing, without rename() being allowed for _anything_.
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2019-03-17 20:38 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-17 20:04 [PATCH 0/5] fscrypt: d_revalidate fixes and cleanups Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` [PATCH 1/5] fscrypt: clean up and improve dentry revalidation Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:38 ` Al Viro [this message]
2019-03-17 20:38 ` Al Viro
2019-03-17 20:38 ` Al Viro
2019-03-18 20:29 ` Eric Biggers
2019-03-18 20:29 ` Eric Biggers
2019-03-18 20:29 ` [f2fs-dev] " Eric Biggers
2019-03-18 20:29 ` Eric Biggers
2019-03-18 21:25 ` Al Viro
2019-03-18 21:25 ` Al Viro
2019-03-18 21:25 ` Al Viro
2019-03-17 20:04 ` [PATCH 2/5] fscrypt: fix race allowing rename() and link() of ciphertext dentries Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` [f2fs-dev] " Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` [PATCH 3/5] fs, fscrypt: clear DCACHE_ENCRYPTED_NAME when unaliasing directory Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` [PATCH 4/5] fscrypt: only set dentry_operations on ciphertext dentries Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` [f2fs-dev] " Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` [PATCH 5/5] fscrypt: fix race where ->lookup() marks plaintext dentry as ciphertext Eric Biggers
2019-03-17 20:04 ` Eric Biggers
2019-03-17 20:04 ` [f2fs-dev] " Eric Biggers
2019-03-17 20:04 ` Eric Biggers
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=20190317203822.GH2217@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=ebiggers@kernel.org \
--cc=gaoxiang25@huawei.com \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-f2fs-devel@lists.sourceforge.net \
--cc=linux-fscrypt@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-mtd@lists.infradead.org \
--cc=linux-unionfs@vger.kernel.org \
--cc=sarthakkukreti@chromium.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.