From: Eric Biggers Date: Mon, 28 Dec 2020 19:12:10 +0000 (-0800) Subject: f2fs: prevent creating duplicate encrypted filenames X-Git-Tag: v4.19.165~26 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=218cf245fc6a3aacb0ebe143a4f4a88121104559;p=users%2Fdwmw2%2Flinux.git f2fs: prevent creating duplicate encrypted filenames 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 Signed-off-by: Greg Kroah-Hartman --- 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); }