[PATCH 4.4 17/40] fscrypt: dont set policy for a dead directory - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Hongjie Fang <hongjiefang@asrmicro.com>,
	Eric Biggers <ebiggers@google.com>
Subject: [PATCH 4.4 17/40] fscrypt: dont set policy for a dead directory
Date: Thu, 18 Jul 2019 12:02:13 +0900	[thread overview]
Message-ID: <20190718030045.019515227@linuxfoundation.org> (raw)
In-Reply-To: <20190718030039.676518610@linuxfoundation.org>

From: Hongjie Fang <hongjiefang@asrmicro.com>

commit 5858bdad4d0d0fc18bf29f34c3ac836e0b59441f upstream.

The directory may have been removed when entering
fscrypt_ioctl_set_policy().  If so, the empty_dir() check will return
error for ext4 file system.

ext4_rmdir() sets i_size = 0, then ext4_empty_dir() reports an error
because 'inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)'.  If
the fs is mounted with errors=panic, it will trigger a panic issue.

Add the check IS_DEADDIR() to fix this problem.

Fixes: 9bd8212f981e ("ext4 crypto: add encryption policy and password salt support")
Cc: <stable@vger.kernel.org> # v4.1+
Signed-off-by: Hongjie Fang <hongjiefang@asrmicro.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
 fs/ext4/crypto_policy.c |    2 ++
 fs/f2fs/crypto_policy.c |    2 ++
 2 files changed, 4 insertions(+)

--- a/fs/ext4/crypto_policy.c
+++ b/fs/ext4/crypto_policy.c
@@ -111,6 +111,8 @@ int ext4_process_policy(const struct ext
 	if (!ext4_inode_has_encryption_context(inode)) {
 		if (!S_ISDIR(inode->i_mode))
 			return -EINVAL;
+		if (IS_DEADDIR(inode))
+			return -ENOENT;
 		if (!ext4_empty_dir(inode))
 			return -ENOTEMPTY;
 		return ext4_create_encryption_context_from_policy(inode,
--- a/fs/f2fs/crypto_policy.c
+++ b/fs/f2fs/crypto_policy.c
@@ -99,6 +99,8 @@ int f2fs_process_policy(const struct f2f
 		return -EINVAL;
 
 	if (!f2fs_inode_has_encryption_context(inode)) {
+		if (IS_DEADDIR(inode))
+			return -ENOENT;
 		if (!f2fs_empty_dir(inode))
 			return -ENOTEMPTY;
 		return f2fs_create_encryption_context_from_policy(inode,


