From: Eric Biggers <ebiggers@kernel.org>
To: stable@vger.kernel.org
Cc: linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-mtd@lists.infradead.org
Subject: [PATCH 4.19 3/4] f2fs: prevent creating duplicate encrypted filenames
Date: Mon, 28 Dec 2020 11:12:10 -0800 [thread overview]
Message-ID: <20201228191211.138300-4-ebiggers@kernel.org> (raw)
In-Reply-To: <20201228191211.138300-1-ebiggers@kernel.org>
From: Eric Biggers <ebiggers@google.com>
commit bfc2b7e8518999003a61f91c1deb5e88ed77b07d upstream.
As described in "fscrypt: add fscrypt_is_nokey_name()", it's possible to
create a duplicate filename in an encrypted directory by creating a file
concurrently with adding the directory's encryption key.
Fix this bug on f2fs by rejecting no-key dentries in f2fs_add_link().
Note that the weird check for the current task in f2fs_do_add_link()
seems to make this bug difficult to reproduce on f2fs.
Fixes: 9ea97163c6da ("f2fs crypto: add filename encryption for f2fs_add_link")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201118075609.120337-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
fs/f2fs/f2fs.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 53ffa6fe207a3..aacd8e11758ca 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2857,6 +2857,8 @@ bool f2fs_empty_dir(struct inode *dir);
static inline int f2fs_add_link(struct dentry *dentry, struct inode *inode)
{
+ if (fscrypt_is_nokey_name(dentry))
+ return -ENOKEY;
return f2fs_do_add_link(d_inode(dentry->d_parent), &dentry->d_name,
inode, inode->i_ino, inode->i_mode);
}
--
2.29.2
next prev parent reply other threads:[~2020-12-28 19:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-28 19:12 [PATCH 4.19 0/4] fscrypt: prevent creating duplicate encrypted filenames Eric Biggers
2020-12-28 19:12 ` [PATCH 4.19 1/4] fscrypt: add fscrypt_is_nokey_name() Eric Biggers
2020-12-28 19:12 ` [PATCH 4.19 2/4] ext4: prevent creating duplicate encrypted filenames Eric Biggers
2020-12-28 19:12 ` Eric Biggers [this message]
2020-12-28 19:12 ` [PATCH 4.19 4/4] ubifs: " Eric Biggers
2020-12-30 15:42 ` [PATCH 4.19 0/4] fscrypt: " Greg KH
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