1 files changed, 44 insertions, 156 deletions

diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 6eae3f12ad50..a9a4432d12ba 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -11,11 +11,13 @@
  * This has not yet undergone a rigorous security audit.
  */
 
-#include <linux/namei.h>
-#include <linux/scatterlist.h>
-#include <crypto/hash.h>
 #include <crypto/sha2.h>
 #include <crypto/skcipher.h>
+#include <linux/export.h>
+#include <linux/namei.h>
+#include <linux/scatterlist.h>
+#include <linux/base64.h>
+
 #include "fscrypt_private.h"
 
 /*
@@ -70,17 +72,11 @@ struct fscrypt_nokey_name {
 
 /* Encoded size of max-size no-key name */
 #define FSCRYPT_NOKEY_NAME_MAX_ENCODED \
-		FSCRYPT_BASE64URL_CHARS(FSCRYPT_NOKEY_NAME_MAX)
+		BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX)
 
 static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
 {
-	if (str->len == 1 && str->name[0] == '.')
-		return true;
-
-	if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
-		return true;
-
-	return false;
+	return is_dot_dotdot(str->name, str->len);
 }
 
 /**
@@ -98,13 +94,12 @@ static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
 int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 			  u8 *out, unsigned int olen)
 {
-	struct skcipher_request *req = NULL;
-	DECLARE_CRYPTO_WAIT(wait);
-	const struct fscrypt_info *ci = inode->i_crypt_info;
-	struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
+	const struct fscrypt_inode_info *ci = fscrypt_get_inode_info_raw(inode);
+	struct crypto_sync_skcipher *tfm = ci->ci_enc_key.tfm;
+	SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
 	union fscrypt_iv iv;
 	struct scatterlist sg;
-	int res;
+	int err;
 
 	/*
 	 * Copy the filename to the output buffer for encrypting in-place and
@@ -115,28 +110,17 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 	memcpy(out, iname->name, iname->len);
 	memset(out + iname->len, 0, olen - iname->len);
 
-	/* Initialize the IV */
 	fscrypt_generate_iv(&iv, 0, ci);
 
-	/* Set up the encryption request */
-	req = skcipher_request_alloc(tfm, GFP_NOFS);
-	if (!req)
-		return -ENOMEM;
-	skcipher_request_set_callback(req,
-			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-			crypto_req_done, &wait);
+	skcipher_request_set_callback(
+		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+		NULL, NULL);
 	sg_init_one(&sg, out, olen);
 	skcipher_request_set_crypt(req, &sg, &sg, olen, &iv);
-
-	/* Do the encryption */
-	res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
-	skcipher_request_free(req);
-	if (res < 0) {
-		fscrypt_err(inode, "Filename encryption failed: %d", res);
-		return res;
-	}
-
-	return 0;
+	err = crypto_skcipher_encrypt(req);
+	if (err)
+		fscrypt_err(inode, "Filename encryption failed: %d", err);
+	return err;
 }
 EXPORT_SYMBOL_GPL(fscrypt_fname_encrypt);
 
@@ -154,118 +138,31 @@ static int fname_decrypt(const struct inode *inode,
 			 const struct fscrypt_str *iname,
 			 struct fscrypt_str *oname)
 {
-	struct skcipher_request *req = NULL;
-	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_enc_key.tfm;
+	const struct fscrypt_inode_info *ci = fscrypt_get_inode_info_raw(inode);
+	struct crypto_sync_skcipher *tfm = ci->ci_enc_key.tfm;
+	SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
 	union fscrypt_iv iv;
-	int res;
-
-	/* Allocate request */
-	req = skcipher_request_alloc(tfm, GFP_NOFS);
-	if (!req)
-		return -ENOMEM;
-	skcipher_request_set_callback(req,
-		CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-		crypto_req_done, &wait);
+	struct scatterlist src_sg, dst_sg;
+	int err;
 
-	/* Initialize IV */
 	fscrypt_generate_iv(&iv, 0, ci);
 
-	/* Create decryption request */
+	skcipher_request_set_callback(
+		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+		NULL, NULL);
 	sg_init_one(&src_sg, iname->name, iname->len);
 	sg_init_one(&dst_sg, oname->name, oname->len);
 	skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, &iv);
-	res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
-	skcipher_request_free(req);
-	if (res < 0) {
-		fscrypt_err(inode, "Filename decryption failed: %d", res);
-		return res;
+	err = crypto_skcipher_decrypt(req);
+	if (err) {
+		fscrypt_err(inode, "Filename decryption failed: %d", err);
+		return err;
 	}
 
 	oname->len = strnlen(oname->name, iname->len);
 	return 0;
 }
 
-static const char base64url_table[65] =
-	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
-
-#define FSCRYPT_BASE64URL_CHARS(nbytes)	DIV_ROUND_UP((nbytes) * 4, 3)
-
-/**
- * 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 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: the length of the resulting base64url-encoded string in bytes.
- *	   This will be equal to FSCRYPT_BASE64URL_CHARS(srclen).
- */
-static int fscrypt_base64url_encode(const u8 *src, int srclen, char *dst)
-{
-	u32 ac = 0;
-	int bits = 0;
-	int i;
-	char *cp = dst;
-
-	for (i = 0; i < srclen; i++) {
-		ac = (ac << 8) | src[i];
-		bits += 8;
-		do {
-			bits -= 6;
-			*cp++ = base64url_table[(ac >> bits) & 0x3f];
-		} while (bits >= 6);
-	}
-	if (bits)
-		*cp++ = base64url_table[(ac << (6 - bits)) & 0x3f];
-	return cp - 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)
-{
-	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]);
-
-		if (p == NULL || src[i] == 0)
-			return -1;
-		ac = (ac << 6) | (p - base64url_table);
-		bits += 6;
-		if (bits >= 8) {
-			bits -= 8;
-			*bp++ = (u8)(ac >> bits);
-		}
-	}
-	if (ac & ((1 << bits) - 1))
-		return -1;
-	return bp - dst;
-}
-
 bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
 				    u32 orig_len, u32 max_len,
 				    u32 *encrypted_len_ret)
@@ -299,8 +196,9 @@ bool __fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
 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,
+	const struct fscrypt_inode_info *ci = fscrypt_get_inode_info_raw(inode);
+
+	return __fscrypt_fname_encrypted_size(&ci->ci_policy, orig_len, max_len,
 					      encrypted_len_ret);
 }
 EXPORT_SYMBOL_GPL(fscrypt_fname_encrypted_size);
@@ -412,8 +310,8 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode,
 		       nokey_name.sha256);
 		size = FSCRYPT_NOKEY_NAME_MAX;
 	}
-	oname->len = fscrypt_base64url_encode((const u8 *)&nokey_name, size,
-					      oname->name);
+	oname->len = base64_encode((const u8 *)&nokey_name, size,
+				   oname->name, false, BASE64_URLSAFE);
 	return 0;
 }
 EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
@@ -492,8 +390,8 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 	if (fname->crypto_buf.name == NULL)
 		return -ENOMEM;
 
-	ret = fscrypt_base64url_decode(iname->name, iname->len,
-				       fname->crypto_buf.name);
+	ret = base64_decode(iname->name, iname->len,
+			    fname->crypto_buf.name, false, BASE64_URLSAFE);
 	if (ret < (int)offsetof(struct fscrypt_nokey_name, bytes[1]) ||
 	    (ret > offsetof(struct fscrypt_nokey_name, sha256) &&
 	     ret != FSCRYPT_NOKEY_NAME_MAX)) {
@@ -568,7 +466,7 @@ EXPORT_SYMBOL_GPL(fscrypt_match_name);
  */
 u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name)
 {
-	const struct fscrypt_info *ci = dir->i_crypt_info;
+	const struct fscrypt_inode_info *ci = fscrypt_get_inode_info_raw(dir);
 
 	WARN_ON_ONCE(!ci->ci_dirhash_key_initialized);
 
@@ -580,11 +478,10 @@ 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.
  */
-int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
+int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
+			 struct dentry *dentry, unsigned int flags)
 {
-	struct dentry *dir;
 	int err;
-	int valid;
 
 	/*
 	 * Plaintext names are always valid, since fscrypt doesn't support
@@ -597,30 +494,21 @@ int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 	/*
 	 * No-key name; valid if the directory's key is still unavailable.
 	 *
-	 * 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
-	 * elsewhere.  Thus ->d_parent can be changing, and we must safely grab
-	 * a reference to some ->d_parent to prevent it from being freed.
+	 * Note in RCU mode we have to bail if we get here -
+	 * fscrypt_get_encryption_info() may block.
 	 */
 
 	if (flags & LOOKUP_RCU)
 		return -ECHILD;
 
-	dir = dget_parent(dentry);
 	/*
 	 * 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);
-
+	err = fscrypt_get_encryption_info(dir, true);
 	if (err < 0)
 		return err;
 
-	return valid;
+	return !fscrypt_has_encryption_key(dir);
 }
 EXPORT_SYMBOL_GPL(fscrypt_d_revalidate);