A code cleanup and bugfix for fs/crypto.

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Merge tag 'fscrypt-for-linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt

Pull fscrypto fixes from Ted Ts'o:
 "A code cleanup and bugfix for fs/crypto"

* tag 'fscrypt-for-linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt:
  fscrypt: eliminate ->prepare_context() operation
  fscrypt: remove broken support for detecting keyring key revocation

fs/crypto/crypto.c

@@ -327,7 +327,6 @@ EXPORT_SYMBOL(fscrypt_decrypt_page);
 static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
 	struct dentry *dir;
-	struct fscrypt_info *ci;
 	int dir_has_key, cached_with_key;
 
 	if (flags & LOOKUP_RCU)
@@ -339,18 +338,11 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
 		return 0;
 	}
 
-	ci = d_inode(dir)->i_crypt_info;
-	if (ci && ci->ci_keyring_key &&
-	    (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
-					  (1 << KEY_FLAG_REVOKED) |
-					  (1 << KEY_FLAG_DEAD))))
-		ci = NULL;
-
 	/* this should eventually be an flag in d_flags */
 	spin_lock(&dentry->d_lock);
 	cached_with_key = dentry->d_flags & DCACHE_ENCRYPTED_WITH_KEY;
 	spin_unlock(&dentry->d_lock);
-	dir_has_key = (ci != NULL);
+	dir_has_key = (d_inode(dir)->i_crypt_info != NULL);
 	dput(dir);
 
 	/*

fs/crypto/fname.c

@@ -350,7 +350,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 		fname->disk_name.len = iname->len;
 		return 0;
 	}
-	ret = fscrypt_get_crypt_info(dir);
+	ret = fscrypt_get_encryption_info(dir);
 	if (ret && ret != -EOPNOTSUPP)
 		return ret;
 

fs/crypto/fscrypt_private.h

@@ -67,7 +67,6 @@ struct fscrypt_info {
 	u8 ci_filename_mode;
 	u8 ci_flags;
 	struct crypto_skcipher *ci_ctfm;
-	struct key *ci_keyring_key;
 	u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
 };
 
@@ -101,7 +100,4 @@ extern int fscrypt_do_page_crypto(const struct inode *inode,
 extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
 					      gfp_t gfp_flags);
 
-/* keyinfo.c */
-extern int fscrypt_get_crypt_info(struct inode *);
-
 #endif /* _FSCRYPT_PRIVATE_H */

fs/crypto/keyinfo.c

@@ -95,6 +95,7 @@ static int validate_user_key(struct fscrypt_info *crypt_info,
 	kfree(description);
 	if (IS_ERR(keyring_key))
 		return PTR_ERR(keyring_key);
+	down_read(&keyring_key->sem);
 
 	if (keyring_key->type != &key_type_logon) {
 		printk_once(KERN_WARNING
@@ -102,11 +103,9 @@ static int validate_user_key(struct fscrypt_info *crypt_info,
 		res = -ENOKEY;
 		goto out;
 	}
-	down_read(&keyring_key->sem);
 	ukp = user_key_payload_locked(keyring_key);
 	if (ukp->datalen != sizeof(struct fscrypt_key)) {
 		res = -EINVAL;
-		up_read(&keyring_key->sem);
 		goto out;
 	}
 	master_key = (struct fscrypt_key *)ukp->data;
@@ -117,17 +116,11 @@ static int validate_user_key(struct fscrypt_info *crypt_info,
 				"%s: key size incorrect: %d\n",
 				__func__, master_key->size);
 		res = -ENOKEY;
-		up_read(&keyring_key->sem);
 		goto out;
 	}
 	res = derive_key_aes(ctx->nonce, master_key->raw, raw_key);
-	up_read(&keyring_key->sem);
-	if (res)
-		goto out;
-
-	crypt_info->ci_keyring_key = keyring_key;
-	return 0;
 out:
+	up_read(&keyring_key->sem);
 	key_put(keyring_key);
 	return res;
 }
@@ -169,12 +162,11 @@ static void put_crypt_info(struct fscrypt_info *ci)
 	if (!ci)
 		return;
 
-	key_put(ci->ci_keyring_key);
 	crypto_free_skcipher(ci->ci_ctfm);
 	kmem_cache_free(fscrypt_info_cachep, ci);
 }
 
-int fscrypt_get_crypt_info(struct inode *inode)
+int fscrypt_get_encryption_info(struct inode *inode)
 {
 	struct fscrypt_info *crypt_info;
 	struct fscrypt_context ctx;
@@ -184,21 +176,15 @@ int fscrypt_get_crypt_info(struct inode *inode)
 	u8 *raw_key = NULL;
 	int res;
 
+	if (inode->i_crypt_info)
+		return 0;
+
 	res = fscrypt_initialize(inode->i_sb->s_cop->flags);
 	if (res)
 		return res;
 
 	if (!inode->i_sb->s_cop->get_context)
 		return -EOPNOTSUPP;
-retry:
-	crypt_info = ACCESS_ONCE(inode->i_crypt_info);
-	if (crypt_info) {
-		if (!crypt_info->ci_keyring_key ||
-				key_validate(crypt_info->ci_keyring_key) == 0)
-			return 0;
-		fscrypt_put_encryption_info(inode, crypt_info);
-		goto retry;
-	}
 
 	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
 	if (res < 0) {
@@ -229,7 +215,6 @@ retry:
 	crypt_info->ci_data_mode = ctx.contents_encryption_mode;
 	crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
 	crypt_info->ci_ctfm = NULL;
-	crypt_info->ci_keyring_key = NULL;
 	memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
 				sizeof(crypt_info->ci_master_key));
 
@@ -273,14 +258,8 @@ retry:
 	if (res)
 		goto out;
 
-	kzfree(raw_key);
+	if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) == NULL)
-	raw_key = NULL;
+		crypt_info = NULL;
-	if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) != NULL) {
-		put_crypt_info(crypt_info);
-		goto retry;
-	}
-	return 0;
-
 out:
 	if (res == -ENOKEY)
 		res = 0;
@@ -288,6 +267,7 @@ out:
 	kzfree(raw_key);
 	return res;
 }
+EXPORT_SYMBOL(fscrypt_get_encryption_info);
 
 void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci)
 {
@@ -305,17 +285,3 @@ void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci)
 	put_crypt_info(ci);
 }
 EXPORT_SYMBOL(fscrypt_put_encryption_info);
-
-int fscrypt_get_encryption_info(struct inode *inode)
-{
-	struct fscrypt_info *ci = inode->i_crypt_info;
-
-	if (!ci ||
-		(ci->ci_keyring_key &&
-		 (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
-					       (1 << KEY_FLAG_REVOKED) |
-					       (1 << KEY_FLAG_DEAD)))))
-		return fscrypt_get_crypt_info(inode);
-	return 0;
-}
-EXPORT_SYMBOL(fscrypt_get_encryption_info);

fs/crypto/policy.c

@@ -33,17 +33,10 @@ static int create_encryption_context_from_policy(struct inode *inode,
 				const struct fscrypt_policy *policy)
 {
 	struct fscrypt_context ctx;
-	int res;
 
 	if (!inode->i_sb->s_cop->set_context)
 		return -EOPNOTSUPP;
 
-	if (inode->i_sb->s_cop->prepare_context) {
-		res = inode->i_sb->s_cop->prepare_context(inode);
-		if (res)
-			return res;
-	}
-
 	ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
 	memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
 					FS_KEY_DESCRIPTOR_SIZE);

fs/ext4/super.c

@@ -1120,17 +1120,16 @@ static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
 				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
 }
 
-static int ext4_prepare_context(struct inode *inode)
-{
-	return ext4_convert_inline_data(inode);
-}
-
 static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 							void *fs_data)
 {
 	handle_t *handle = fs_data;
 	int res, res2, retries = 0;
 
+	res = ext4_convert_inline_data(inode);
+	if (res)
+		return res;
+
 	/*
 	 * If a journal handle was specified, then the encryption context is
 	 * being set on a new inode via inheritance and is part of a larger
@@ -1196,7 +1195,6 @@ static unsigned ext4_max_namelen(struct inode *inode)
 static const struct fscrypt_operations ext4_cryptops = {
 	.key_prefix		= "ext4:",
 	.get_context		= ext4_get_context,
-	.prepare_context	= ext4_prepare_context,
 	.set_context		= ext4_set_context,
 	.dummy_context		= ext4_dummy_context,
 	.is_encrypted		= ext4_encrypted_inode,

include/linux/fscrypt_common.h

@@ -87,7 +87,6 @@ struct fscrypt_operations {
 	unsigned int flags;
 	const char *key_prefix;
 	int (*get_context)(struct inode *, void *, size_t);
-	int (*prepare_context)(struct inode *);
 	int (*set_context)(struct inode *, const void *, size_t, void *);
 	int (*dummy_context)(struct inode *);
 	bool (*is_encrypted)(struct inode *);