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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 4.19 56/91] fscrypt: dont set policy for a dead directory
Date:   Fri, 12 Jul 2019 14:18:59 +0200
Message-Id: <20190712121624.716511060@linuxfoundation.org>
In-Reply-To: <20190712121621.422224300@linuxfoundation.org>
References: <20190712121621.422224300@linuxfoundation.org>
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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/crypto/policy.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -81,6 +81,8 @@ int fscrypt_ioctl_set_policy(struct file
 	if (ret == -ENODATA) {
 		if (!S_ISDIR(inode->i_mode))
 			ret = -ENOTDIR;
+		else if (IS_DEADDIR(inode))
+			ret = -ENOENT;
 		else if (!inode->i_sb->s_cop->empty_dir(inode))
 			ret = -ENOTEMPTY;
 		else