1 files changed, 29 insertions, 12 deletions

diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 0f9961eede1e..ed115acb5dee 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -11,6 +11,7 @@
 #include <linux/random.h>
 #include <linux/string.h>
 #include <linux/fscrypto.h>
+#include <linux/mount.h>
 
 static int inode_has_encryption_context(struct inode *inode)
 {
@@ -92,26 +93,42 @@ static int create_encryption_context_from_policy(struct inode *inode,
 	return inode->i_sb->s_cop->set_context(inode, &ctx, sizeof(ctx), NULL);
 }
 
-int fscrypt_process_policy(struct inode *inode,
+int fscrypt_process_policy(struct file *filp,
 				const struct fscrypt_policy *policy)
 {
+	struct inode *inode = file_inode(filp);
+	int ret;
+
+	if (!inode_owner_or_capable(inode))
+		return -EACCES;
+
 	if (policy->version != 0)
 		return -EINVAL;
 
+	ret = mnt_want_write_file(filp);
+	if (ret)
+		return ret;
+
 	if (!inode_has_encryption_context(inode)) {
-		if (!inode->i_sb->s_cop->empty_dir)
-			return -EOPNOTSUPP;
-		if (!inode->i_sb->s_cop->empty_dir(inode))
-			return -ENOTEMPTY;
-		return create_encryption_context_from_policy(inode, policy);
+		if (!S_ISDIR(inode->i_mode))
+			ret = -EINVAL;
+		else if (!inode->i_sb->s_cop->empty_dir)
+			ret = -EOPNOTSUPP;
+		else if (!inode->i_sb->s_cop->empty_dir(inode))
+			ret = -ENOTEMPTY;
+		else
+			ret = create_encryption_context_from_policy(inode,
+								    policy);
+	} else if (!is_encryption_context_consistent_with_policy(inode,
+								 policy)) {
+		printk(KERN_WARNING
+		       "%s: Policy inconsistent with encryption context\n",
+		       __func__);
+		ret = -EINVAL;
 	}
 
-	if (is_encryption_context_consistent_with_policy(inode, policy))
-		return 0;
-
-	printk(KERN_WARNING "%s: Policy inconsistent with encryption context\n",
-	       __func__);
-	return -EINVAL;
+	mnt_drop_write_file(filp);
+	return ret;
 }
 EXPORT_SYMBOL(fscrypt_process_policy);