1 files changed, 166 insertions, 128 deletions

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 4c212442a8f7..12bd61d20f69 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -14,11 +14,18 @@
 #include <linux/namei.h>
 #include <linux/scatterlist.h>
 #include <crypto/hash.h>
-#include <crypto/sha.h>
+#include <crypto/sha2.h>
 #include <crypto/skcipher.h>
 #include "fscrypt_private.h"
 
-/**
+/*
+ * The minimum message length (input and output length), in bytes, for all
+ * filenames encryption modes.  Filenames shorter than this will be zero-padded
+ * before being encrypted.
+ */
+#define FSCRYPT_FNAME_MIN_MSG_LEN 16
+
+/*
  * struct fscrypt_nokey_name - identifier for directory entry when key is absent
  *
  * When userspace lists an encrypted directory without access to the key, the
@@ -26,7 +33,7 @@
  * it to find the directory entry again if requested.  Naively, that would just
  * mean using the ciphertext filenames.  However, since the ciphertext filenames
  * can contain illegal characters ('\0' and '/'), they must be encoded in some
- * way.  We use base64.  But that can cause names to exceed NAME_MAX (255
+ * way.  We use base64url.  But that can cause names to exceed NAME_MAX (255
  * bytes), so we also need to use a strong hash to abbreviate long names.
  *
  * The filesystem may also need another kind of hash, the "dirhash", to quickly
@@ -38,7 +45,7 @@
  * casefolded directories use this type of dirhash.  At least in these cases,
  * each no-key name must include the name's dirhash too.
  *
- * To meet all these requirements, we base64-encode the following
+ * To meet all these requirements, we base64url-encode the following
  * variable-length structure.  It contains the dirhash, or 0's if the filesystem
  * didn't provide one; up to 149 bytes of the ciphertext name; and for
  * ciphertexts longer than 149 bytes, also the SHA-256 of the remaining bytes.
@@ -52,45 +59,18 @@ struct fscrypt_nokey_name {
 	u32 dirhash[2];
 	u8 bytes[149];
 	u8 sha256[SHA256_DIGEST_SIZE];
-}; /* 189 bytes => 252 bytes base64-encoded, which is <= NAME_MAX (255) */
+}; /* 189 bytes => 252 bytes base64url-encoded, which is <= NAME_MAX (255) */
 
 /*
- * Decoded size of max-size nokey name, i.e. a name that was abbreviated using
+ * Decoded size of max-size no-key name, i.e. a name that was abbreviated using
  * the strong hash and thus includes the 'sha256' field.  This isn't simply
  * sizeof(struct fscrypt_nokey_name), as the padding at the end isn't included.
  */
 #define FSCRYPT_NOKEY_NAME_MAX	offsetofend(struct fscrypt_nokey_name, sha256)
 
-static struct crypto_shash *sha256_hash_tfm;
-
-static int fscrypt_do_sha256(const u8 *data, unsigned int data_len, u8 *result)
-{
-	struct crypto_shash *tfm = READ_ONCE(sha256_hash_tfm);
-
-	if (unlikely(!tfm)) {
-		struct crypto_shash *prev_tfm;
-
-		tfm = crypto_alloc_shash("sha256", 0, 0);
-		if (IS_ERR(tfm)) {
-			fscrypt_err(NULL,
-				    "Error allocating SHA-256 transform: %ld",
-				    PTR_ERR(tfm));
-			return PTR_ERR(tfm);
-		}
-		prev_tfm = cmpxchg(&sha256_hash_tfm, NULL, tfm);
-		if (prev_tfm) {
-			crypto_free_shash(tfm);
-			tfm = prev_tfm;
-		}
-	}
-	{
-		SHASH_DESC_ON_STACK(desc, tfm);
-
-		desc->tfm = tfm;
-
-		return crypto_shash_digest(desc, data, data_len, result);
-	}
-}
+/* Encoded size of max-size no-key name */
+#define FSCRYPT_NOKEY_NAME_MAX_ENCODED \
+		FSCRYPT_BASE64URL_CHARS(FSCRYPT_NOKEY_NAME_MAX)
 
 static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
 {
@@ -105,9 +85,13 @@ static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
 
 /**
  * fscrypt_fname_encrypt() - encrypt a filename
- *
- * The output buffer must be at least as large as the input buffer.
- * Any extra space is filled with NUL padding before encryption.
+ * @inode: inode of the parent directory (for regular filenames)
+ *	   or of the symlink (for symlink targets). Key must already be
+ *	   set up.
+ * @iname: the filename to encrypt
+ * @out: (output) the encrypted filename
+ * @olen: size of the encrypted filename.  It must be at least @iname->len.
+ *	  Any extra space is filled with NUL padding before encryption.
  *
  * Return: 0 on success, -errno on failure
  */
@@ -117,7 +101,7 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 	struct skcipher_request *req = NULL;
 	DECLARE_CRYPTO_WAIT(wait);
 	const struct fscrypt_info *ci = inode->i_crypt_info;
-	struct crypto_skcipher *tfm = ci->ci_ctfm;
+	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
 	union fscrypt_iv iv;
 	struct scatterlist sg;
 	int res;
@@ -154,11 +138,15 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(fscrypt_fname_encrypt);
 
 /**
  * fname_decrypt() - decrypt a filename
- *
- * The caller must have allocated sufficient memory for the @oname string.
+ * @inode: inode of the parent directory (for regular filenames)
+ *	   or of the symlink (for symlink targets)
+ * @iname: the encrypted filename to decrypt
+ * @oname: (output) the decrypted filename.  The caller must have allocated
+ *	   enough space for this, e.g. using fscrypt_fname_alloc_buffer().
  *
  * Return: 0 on success, -errno on failure
  */
@@ -170,7 +158,7 @@ static int fname_decrypt(const struct inode *inode,
 	DECLARE_CRYPTO_WAIT(wait);
 	struct scatterlist src_sg, dst_sg;
 	const struct fscrypt_info *ci = inode->i_crypt_info;
-	struct crypto_skcipher *tfm = ci->ci_ctfm;
+	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
 	union fscrypt_iv iv;
 	int res;
 
@@ -200,93 +188,139 @@ static int fname_decrypt(const struct inode *inode,
 	return 0;
 }
 
-static const char lookup_table[65] =
-	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
+static const char base64url_table[65] =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
 
-#define BASE64_CHARS(nbytes)	DIV_ROUND_UP((nbytes) * 4, 3)
+#define FSCRYPT_BASE64URL_CHARS(nbytes)	DIV_ROUND_UP((nbytes) * 4, 3)
 
 /**
- * base64_encode() -
+ * fscrypt_base64url_encode() - base64url-encode some binary data
+ * @src: the binary data to encode
+ * @srclen: the length of @src in bytes
+ * @dst: (output) the base64url-encoded string.  Not NUL-terminated.
  *
- * Encodes the input string using characters from the set [A-Za-z0-9+,].
- * The encoded string is roughly 4/3 times the size of the input string.
+ * Encodes data using base64url encoding, i.e. the "Base 64 Encoding with URL
+ * and Filename Safe Alphabet" specified by RFC 4648.  '='-padding isn't used,
+ * as it's unneeded and not required by the RFC.  base64url is used instead of
+ * base64 to avoid the '/' character, which isn't allowed in filenames.
  *
- * Return: length of the encoded string
+ * Return: the length of the resulting base64url-encoded string in bytes.
+ *	   This will be equal to FSCRYPT_BASE64URL_CHARS(srclen).
  */
-static int base64_encode(const u8 *src, int len, char *dst)
+static int fscrypt_base64url_encode(const u8 *src, int srclen, char *dst)
 {
-	int i, bits = 0, ac = 0;
+	u32 ac = 0;
+	int bits = 0;
+	int i;
 	char *cp = dst;
 
-	for (i = 0; i < len; i++) {
-		ac += src[i] << bits;
+	for (i = 0; i < srclen; i++) {
+		ac = (ac << 8) | src[i];
 		bits += 8;
 		do {
-			*cp++ = lookup_table[ac & 0x3f];
-			ac >>= 6;
 			bits -= 6;
+			*cp++ = base64url_table[(ac >> bits) & 0x3f];
 		} while (bits >= 6);
 	}
 	if (bits)
-		*cp++ = lookup_table[ac & 0x3f];
+		*cp++ = base64url_table[(ac << (6 - bits)) & 0x3f];
 	return cp - dst;
 }
 
-static int base64_decode(const char *src, int len, u8 *dst)
+/**
+ * fscrypt_base64url_decode() - base64url-decode a string
+ * @src: the string to decode.  Doesn't need to be NUL-terminated.
+ * @srclen: the length of @src in bytes
+ * @dst: (output) the decoded binary data
+ *
+ * Decodes a string using base64url encoding, i.e. the "Base 64 Encoding with
+ * URL and Filename Safe Alphabet" specified by RFC 4648.  '='-padding isn't
+ * accepted, nor are non-encoding characters such as whitespace.
+ *
+ * This implementation hasn't been optimized for performance.
+ *
+ * Return: the length of the resulting decoded binary data in bytes,
+ *	   or -1 if the string isn't a valid base64url string.
+ */
+static int fscrypt_base64url_decode(const char *src, int srclen, u8 *dst)
 {
-	int i, bits = 0, ac = 0;
-	const char *p;
-	u8 *cp = dst;
+	u32 ac = 0;
+	int bits = 0;
+	int i;
+	u8 *bp = dst;
+
+	for (i = 0; i < srclen; i++) {
+		const char *p = strchr(base64url_table, src[i]);
 
-	for (i = 0; i < len; i++) {
-		p = strchr(lookup_table, src[i]);
 		if (p == NULL || src[i] == 0)
-			return -2;
-		ac += (p - lookup_table) << bits;
+			return -1;
+		ac = (ac << 6) | (p - base64url_table);
 		bits += 6;
 		if (bits >= 8) {
-			*cp++ = ac & 0xff;
-			ac >>= 8;
 			bits -= 8;
+			*bp++ = (u8)(ac >> bits);
 		}
 	}
-	if (ac)
+	if (ac & ((1 << bits) - 1))
 		return -1;
-	return cp - dst;
+	return bp - dst;
 }
 
-bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
-				  u32 max_len, u32 *encrypted_len_ret)
+bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
+				    u32 orig_len, u32 max_len,
+				    u32 *encrypted_len_ret)
 {
-	const struct fscrypt_info *ci = inode->i_crypt_info;
-	int padding = 4 << (fscrypt_policy_flags(&ci->ci_policy) &
+	int padding = 4 << (fscrypt_policy_flags(policy) &
 			    FSCRYPT_POLICY_FLAGS_PAD_MASK);
 	u32 encrypted_len;
 
 	if (orig_len > max_len)
 		return false;
-	encrypted_len = max(orig_len, (u32)FS_CRYPTO_BLOCK_SIZE);
+	encrypted_len = max_t(u32, orig_len, FSCRYPT_FNAME_MIN_MSG_LEN);
 	encrypted_len = round_up(encrypted_len, padding);
 	*encrypted_len_ret = min(encrypted_len, max_len);
 	return true;
 }
 
 /**
- * fscrypt_fname_alloc_buffer - allocate a buffer for presented filenames
+ * fscrypt_fname_encrypted_size() - calculate length of encrypted filename
+ * @inode:		parent inode of dentry name being encrypted. Key must
+ *			already be set up.
+ * @orig_len:		length of the original filename
+ * @max_len:		maximum length to return
+ * @encrypted_len_ret:	where calculated length should be returned (on success)
+ *
+ * Filenames that are shorter than the maximum length may have their lengths
+ * increased slightly by encryption, due to padding that is applied.
+ *
+ * Return: false if the orig_len is greater than max_len. Otherwise, true and
+ *	   fill out encrypted_len_ret with the length (up to max_len).
+ */
+bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
+				  u32 max_len, u32 *encrypted_len_ret)
+{
+	return __fscrypt_fname_encrypted_size(&inode->i_crypt_info->ci_policy,
+					      orig_len, max_len,
+					      encrypted_len_ret);
+}
+EXPORT_SYMBOL_GPL(fscrypt_fname_encrypted_size);
+
+/**
+ * fscrypt_fname_alloc_buffer() - allocate a buffer for presented filenames
+ * @max_encrypted_len: maximum length of encrypted filenames the buffer will be
+ *		       used to present
+ * @crypto_str: (output) buffer to allocate
  *
  * Allocate a buffer that is large enough to hold any decrypted or encoded
  * filename (null-terminated), for the given maximum encrypted filename length.
  *
  * Return: 0 on success, -errno on failure
  */
-int fscrypt_fname_alloc_buffer(const struct inode *inode,
-			       u32 max_encrypted_len,
+int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
 			       struct fscrypt_str *crypto_str)
 {
-	const u32 max_encoded_len = BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX);
-	u32 max_presented_len;
-
-	max_presented_len = max(max_encoded_len, max_encrypted_len);
+	u32 max_presented_len = max_t(u32, FSCRYPT_NOKEY_NAME_MAX_ENCODED,
+				      max_encrypted_len);
 
 	crypto_str->name = kmalloc(max_presented_len + 1, GFP_NOFS);
 	if (!crypto_str->name)
@@ -297,9 +331,10 @@ int fscrypt_fname_alloc_buffer(const struct inode *inode,
 EXPORT_SYMBOL(fscrypt_fname_alloc_buffer);
 
 /**
- * fscrypt_fname_free_buffer - free the buffer for presented filenames
+ * fscrypt_fname_free_buffer() - free a buffer for presented filenames
+ * @crypto_str: the buffer to free
  *
- * Free the buffer allocated by fscrypt_fname_alloc_buffer().
+ * Free a buffer that was allocated by fscrypt_fname_alloc_buffer().
  */
 void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
 {
@@ -311,10 +346,19 @@ void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
 EXPORT_SYMBOL(fscrypt_fname_free_buffer);
 
 /**
- * fscrypt_fname_disk_to_usr() - converts a filename from disk space to user
- * space
- *
- * The caller must have allocated sufficient memory for the @oname string.
+ * fscrypt_fname_disk_to_usr() - convert an encrypted filename to
+ *				 user-presentable form
+ * @inode: inode of the parent directory (for regular filenames)
+ *	   or of the symlink (for symlink targets)
+ * @hash: first part of the name's dirhash, if applicable.  This only needs to
+ *	  be provided if the filename is located in an indexed directory whose
+ *	  encryption key may be unavailable.  Not needed for symlink targets.
+ * @minor_hash: second part of the name's dirhash, if applicable
+ * @iname: encrypted filename to convert.  May also be "." or "..", which
+ *	   aren't actually encrypted.
+ * @oname: output buffer for the user-presentable filename.  The caller must
+ *	   have allocated enough space for this, e.g. using
+ *	   fscrypt_fname_alloc_buffer().
  *
  * If the key is available, we'll decrypt the disk name.  Otherwise, we'll
  * encode it for presentation in fscrypt_nokey_name format.
@@ -330,7 +374,6 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode,
 	const struct qstr qname = FSTR_TO_QSTR(iname);
 	struct fscrypt_nokey_name nokey_name;
 	u32 size; /* size of the unencoded no-key name */
-	int err;
 
 	if (fscrypt_is_dot_dotdot(&qname)) {
 		oname->name[0] = '.';
@@ -339,7 +382,7 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode,
 		return 0;
 	}
 
-	if (iname->len < FS_CRYPTO_BLOCK_SIZE)
+	if (iname->len < FSCRYPT_FNAME_MIN_MSG_LEN)
 		return -EUCLEAN;
 
 	if (fscrypt_has_encryption_key(inode))
@@ -353,29 +396,24 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode,
 		     offsetof(struct fscrypt_nokey_name, bytes));
 	BUILD_BUG_ON(offsetofend(struct fscrypt_nokey_name, bytes) !=
 		     offsetof(struct fscrypt_nokey_name, sha256));
-	BUILD_BUG_ON(BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX) > NAME_MAX);
+	BUILD_BUG_ON(FSCRYPT_NOKEY_NAME_MAX_ENCODED > NAME_MAX);
+
+	nokey_name.dirhash[0] = hash;
+	nokey_name.dirhash[1] = minor_hash;
 
-	if (hash) {
-		nokey_name.dirhash[0] = hash;
-		nokey_name.dirhash[1] = minor_hash;
-	} else {
-		nokey_name.dirhash[0] = 0;
-		nokey_name.dirhash[1] = 0;
-	}
 	if (iname->len <= sizeof(nokey_name.bytes)) {
 		memcpy(nokey_name.bytes, iname->name, iname->len);
 		size = offsetof(struct fscrypt_nokey_name, bytes[iname->len]);
 	} else {
 		memcpy(nokey_name.bytes, iname->name, sizeof(nokey_name.bytes));
 		/* Compute strong hash of remaining part of name. */
-		err = fscrypt_do_sha256(&iname->name[sizeof(nokey_name.bytes)],
-					iname->len - sizeof(nokey_name.bytes),
-					nokey_name.sha256);
-		if (err)
-			return err;
+		sha256(&iname->name[sizeof(nokey_name.bytes)],
+		       iname->len - sizeof(nokey_name.bytes),
+		       nokey_name.sha256);
 		size = FSCRYPT_NOKEY_NAME_MAX;
 	}
-	oname->len = base64_encode((const u8 *)&nokey_name, size, oname->name);
+	oname->len = fscrypt_base64url_encode((const u8 *)&nokey_name, size,
+					      oname->name);
 	return 0;
 }
 EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
@@ -395,9 +433,9 @@ EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
  * directory's encryption key, then @iname is the plaintext, so we encrypt it to
  * get the disk_name.
  *
- * Else, for keyless @lookup operations, @iname is the presented ciphertext, so
- * we decode it to get the fscrypt_nokey_name.  Non-@lookup operations will be
- * impossible in this case, so we fail them with ENOKEY.
+ * Else, for keyless @lookup operations, @iname should be a no-key name, so we
+ * decode it to get the struct fscrypt_nokey_name.  Non-@lookup operations will
+ * be impossible in this case, so we fail them with ENOKEY.
  *
  * If successful, fscrypt_free_filename() must be called later to clean up.
  *
@@ -417,13 +455,12 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 		fname->disk_name.len = iname->len;
 		return 0;
 	}
-	ret = fscrypt_get_encryption_info(dir);
+	ret = fscrypt_get_encryption_info(dir, lookup);
 	if (ret)
 		return ret;
 
 	if (fscrypt_has_encryption_key(dir)) {
-		if (!fscrypt_fname_encrypted_size(dir, iname->len,
-						  dir->i_sb->s_cop->max_namelen,
+		if (!fscrypt_fname_encrypted_size(dir, iname->len, NAME_MAX,
 						  &fname->crypto_buf.len))
 			return -ENAMETOOLONG;
 		fname->crypto_buf.name = kmalloc(fname->crypto_buf.len,
@@ -441,21 +478,22 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 	}
 	if (!lookup)
 		return -ENOKEY;
-	fname->is_ciphertext_name = true;
+	fname->is_nokey_name = true;
 
 	/*
 	 * We don't have the key and we are doing a lookup; decode the
 	 * user-supplied name
 	 */
 
-	if (iname->len > BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX))
+	if (iname->len > FSCRYPT_NOKEY_NAME_MAX_ENCODED)
 		return -ENOENT;
 
 	fname->crypto_buf.name = kmalloc(FSCRYPT_NOKEY_NAME_MAX, GFP_KERNEL);
 	if (fname->crypto_buf.name == NULL)
 		return -ENOMEM;
 
-	ret = base64_decode(iname->name, iname->len, fname->crypto_buf.name);
+	ret = fscrypt_base64url_decode(iname->name, iname->len,
+				       fname->crypto_buf.name);
 	if (ret < (int)offsetof(struct fscrypt_nokey_name, bytes[1]) ||
 	    (ret > offsetof(struct fscrypt_nokey_name, sha256) &&
 	     ret != FSCRYPT_NOKEY_NAME_MAX)) {
@@ -500,7 +538,7 @@ bool fscrypt_match_name(const struct fscrypt_name *fname,
 {
 	const struct fscrypt_nokey_name *nokey_name =
 		(const void *)fname->crypto_buf.name;
-	u8 sha256[SHA256_DIGEST_SIZE];
+	u8 digest[SHA256_DIGEST_SIZE];
 
 	if (likely(fname->disk_name.name)) {
 		if (de_name_len != fname->disk_name.len)
@@ -511,10 +549,9 @@ bool fscrypt_match_name(const struct fscrypt_name *fname,
 		return false;
 	if (memcmp(de_name, nokey_name->bytes, sizeof(nokey_name->bytes)))
 		return false;
-	if (fscrypt_do_sha256(&de_name[sizeof(nokey_name->bytes)],
-			      de_name_len - sizeof(nokey_name->bytes), sha256))
-		return false;
-	return !memcmp(sha256, nokey_name->sha256, sizeof(sha256));
+	sha256(&de_name[sizeof(nokey_name->bytes)],
+	       de_name_len - sizeof(nokey_name->bytes), digest);
+	return !memcmp(digest, nokey_name->sha256, sizeof(digest));
 }
 EXPORT_SYMBOL_GPL(fscrypt_match_name);
 
@@ -543,7 +580,7 @@ EXPORT_SYMBOL_GPL(fscrypt_fname_siphash);
  * Validate dentries in encrypted directories to make sure we aren't potentially
  * caching stale dentries after a key has been added.
  */
-static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
+int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
 	struct dentry *dir;
 	int err;
@@ -551,17 +588,17 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 
 	/*
 	 * Plaintext names are always valid, since fscrypt doesn't support
-	 * reverting to ciphertext names without evicting the directory's inode
+	 * reverting to no-key names without evicting the directory's inode
 	 * -- which implies eviction of the dentries in the directory.
 	 */
-	if (!(dentry->d_flags & DCACHE_ENCRYPTED_NAME))
+	if (!(dentry->d_flags & DCACHE_NOKEY_NAME))
 		return 1;
 
 	/*
-	 * Ciphertext name; valid if the directory's key is still unavailable.
+	 * No-key name; valid if the directory's key is still unavailable.
 	 *
-	 * Although fscrypt forbids rename() on ciphertext names, we still must
-	 * use dget_parent() here rather than use ->d_parent directly.  That's
+	 * Although fscrypt forbids rename() on no-key names, we still must use
+	 * dget_parent() here rather than use ->d_parent directly.  That's
 	 * because a corrupted fs image may contain directory hard links, which
 	 * the VFS handles by moving the directory's dentry tree in the dcache
 	 * each time ->lookup() finds the directory and it already has a dentry
@@ -573,7 +610,11 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 		return -ECHILD;
 
 	dir = dget_parent(dentry);
-	err = fscrypt_get_encryption_info(d_inode(dir));
+	/*
+	 * Pass allow_unsupported=true, so that files with an unsupported
+	 * encryption policy can be deleted.
+	 */
+	err = fscrypt_get_encryption_info(d_inode(dir), true);
 	valid = !fscrypt_has_encryption_key(d_inode(dir));
 	dput(dir);
 
@@ -582,7 +623,4 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 
 	return valid;
 }
-
-const struct dentry_operations fscrypt_d_ops = {
-	.d_revalidate = fscrypt_d_revalidate,
-};
+EXPORT_SYMBOL_GPL(fscrypt_d_revalidate);