fs/crypto: catch up 4.9-rc2

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

4 files changed, 129 insertions, 90 deletions

diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index af40768d7..f5bc754ea 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -129,11 +129,11 @@ struct fscrypt_ctx *fscrypt_get_ctx(struct inode *inode, gfp_t gfp_flags)
 EXPORT_SYMBOL(fscrypt_get_ctx);
 
 /**
- * fscrypt_complete() - The completion callback for page encryption
- * @req: The asynchronous encryption request context
- * @res: The result of the encryption operation
+ * page_crypt_complete() - completion callback for page crypto
+ * @req: The asynchronous cipher request context
+ * @res: The result of the cipher operation
  */
-static void fscrypt_complete(struct crypto_async_request *req, int res)
+static void page_crypt_complete(struct crypto_async_request *req, int res)
 {
 	struct fscrypt_completion_result *ecr = req->data;
 
@@ -171,7 +171,7 @@ static int do_page_crypto(struct inode *inode,
 
 	ablkcipher_request_set_callback(
 		req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-		fscrypt_complete, &ecr);
+		page_crypt_complete, &ecr);
 
 	BUILD_BUG_ON(FS_XTS_TWEAK_SIZE < sizeof(index));
 	memcpy(xts_tweak, &index, sizeof(index));
@@ -179,10 +179,10 @@ static int do_page_crypto(struct inode *inode,
 			FS_XTS_TWEAK_SIZE - sizeof(index));
 
 	sg_init_table(&dst, 1);
-	sg_set_page(&dst, dest_page, PAGE_CACHE_SIZE, 0);
+	sg_set_page(&dst, dest_page, PAGE_SIZE, 0);
 	sg_init_table(&src, 1);
-	sg_set_page(&src, src_page, PAGE_CACHE_SIZE, 0);
-	ablkcipher_request_set_crypt(req, &src, &dst, PAGE_CACHE_SIZE,
+	sg_set_page(&src, src_page, PAGE_SIZE, 0);
+	ablkcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE,
 					xts_tweak);
 	if (rw == FS_DECRYPT)
 		res = crypto_ablkcipher_decrypt(req);
@@ -292,7 +292,7 @@ int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk,
 	struct bio *bio;
 	int ret, err = 0;
 
-	BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE);
+	BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
 
 	ctx = fscrypt_get_ctx(inode, GFP_NOFS);
 	if (IS_ERR(ctx))
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 5e4ddeeba..e7035c608 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -19,15 +19,12 @@
 #include <linux/ratelimit.h>
 #include <linux/fscrypto.h>
 
-static u32 size_round_up(size_t size, size_t blksize)
-{
-	return ((size + blksize - 1) / blksize) * blksize;
-}
-
 /**
- * dir_crypt_complete() -
+ * fname_crypt_complete() - completion callback for filename crypto
+ * @req: The asynchronous cipher request context
+ * @res: The result of the cipher operation
  */
-static void dir_crypt_complete(struct crypto_async_request *req, int res)
+static void fname_crypt_complete(struct crypto_async_request *req, int res)
 {
 	struct fscrypt_completion_result *ecr = req->data;
 
@@ -38,11 +35,11 @@ static void dir_crypt_complete(struct crypto_async_request *req, int res)
 }
 
 /**
- * fname_encrypt() -
+ * fname_encrypt() - encrypt a filename
  *
- * This function encrypts the input filename, and returns the length of the
- * ciphertext. Errors are returned as negative numbers.  We trust the caller to
- * allocate sufficient memory to oname string.
+ * The caller must have allocated sufficient memory for the @oname string.
+ *
+ * Return: 0 on success, -errno on failure
  */
 static int fname_encrypt(struct inode *inode,
 			const struct qstr *iname, struct fscrypt_str *oname)
@@ -63,10 +60,9 @@ static int fname_encrypt(struct inode *inode,
 	if (iname->len <= 0 || iname->len > lim)
 		return -EIO;
 
-	ciphertext_len = (iname->len < FS_CRYPTO_BLOCK_SIZE) ?
-					FS_CRYPTO_BLOCK_SIZE : iname->len;
-	ciphertext_len = size_round_up(ciphertext_len, padding);
-	ciphertext_len = (ciphertext_len > lim) ? lim : ciphertext_len;
+	ciphertext_len = max(iname->len, (u32)FS_CRYPTO_BLOCK_SIZE);
+	ciphertext_len = round_up(ciphertext_len, padding);
+	ciphertext_len = min(ciphertext_len, lim);
 
 	if (ciphertext_len <= sizeof(buf)) {
 		workbuf = buf;
@@ -87,7 +83,7 @@ static int fname_encrypt(struct inode *inode,
 	}
 	ablkcipher_request_set_callback(req,
 			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-			dir_crypt_complete, &ecr);
+			fname_crypt_complete, &ecr);
 
 	/* Copy the input */
 	memcpy(workbuf, iname->name, iname->len);
@@ -108,20 +104,22 @@ static int fname_encrypt(struct inode *inode,
 	}
 	kfree(alloc_buf);
 	ablkcipher_request_free(req);
-	if (res < 0)
+	if (res < 0) {
 		printk_ratelimited(KERN_ERR
 				"%s: Error (error code %d)\n", __func__, res);
+		return res;
+	}
 
 	oname->len = ciphertext_len;
-	return res;
+	return 0;
 }
 
-/*
- * fname_decrypt()
- *	This function decrypts the input filename, and returns
- *	the length of the plaintext.
- *	Errors are returned as negative numbers.
- *	We trust the caller to allocate sufficient memory to oname string.
+/**
+ * fname_decrypt() - decrypt a filename
+ *
+ * The caller must have allocated sufficient memory for the @oname string.
+ *
+ * Return: 0 on success, -errno on failure
  */
 static int fname_decrypt(struct inode *inode,
 				const struct fscrypt_str *iname,
@@ -149,7 +147,7 @@ static int fname_decrypt(struct inode *inode,
 	}
 	ablkcipher_request_set_callback(req,
 		CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-		dir_crypt_complete, &ecr);
+		fname_crypt_complete, &ecr);
 
 	/* Initialize IV */
 	memset(iv, 0, FS_CRYPTO_BLOCK_SIZE);
@@ -171,7 +169,7 @@ static int fname_decrypt(struct inode *inode,
 	}
 
 	oname->len = strnlen(oname->name, iname->len);
-	return oname->len;
+	return 0;
 }
 
 static const char *lookup_table =
@@ -234,9 +232,8 @@ u32 fscrypt_fname_encrypted_size(struct inode *inode, u32 ilen)
 
 	if (ci)
 		padding = 4 << (ci->ci_flags & FS_POLICY_FLAGS_PAD_MASK);
-	if (ilen < FS_CRYPTO_BLOCK_SIZE)
-		ilen = FS_CRYPTO_BLOCK_SIZE;
-	return size_round_up(ilen, padding);
+	ilen = max(ilen, (u32)FS_CRYPTO_BLOCK_SIZE);
+	return round_up(ilen, padding);
 }
 EXPORT_SYMBOL(fscrypt_fname_encrypted_size);
 
@@ -282,6 +279,10 @@ 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.
+ *
+ * Return: 0 on success, -errno on failure
  */
 int fscrypt_fname_disk_to_usr(struct inode *inode,
 			u32 hash, u32 minor_hash,
@@ -290,13 +291,12 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
 {
 	const struct qstr qname = FSTR_TO_QSTR(iname);
 	char buf[24];
-	int ret;
 
 	if (fscrypt_is_dot_dotdot(&qname)) {
 		oname->name[0] = '.';
 		oname->name[iname->len - 1] = '.';
 		oname->len = iname->len;
-		return oname->len;
+		return 0;
 	}
 
 	if (iname->len < FS_CRYPTO_BLOCK_SIZE)
@@ -306,9 +306,9 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
 		return fname_decrypt(inode, iname, oname);
 
 	if (iname->len <= FS_FNAME_CRYPTO_DIGEST_SIZE) {
-		ret = digest_encode(iname->name, iname->len, oname->name);
-		oname->len = ret;
-		return ret;
+		oname->len = digest_encode(iname->name, iname->len,
+					   oname->name);
+		return 0;
 	}
 	if (hash) {
 		memcpy(buf, &hash, 4);
@@ -318,15 +318,18 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
 	}
 	memcpy(buf + 8, iname->name + iname->len - 16, 16);
 	oname->name[0] = '_';
-	ret = digest_encode(buf, 24, oname->name + 1);
-	oname->len = ret + 1;
-	return ret + 1;
+	oname->len = 1 + digest_encode(buf, 24, oname->name + 1);
+	return 0;
 }
 EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
 
 /**
  * fscrypt_fname_usr_to_disk() - converts a filename from user space to disk
  * space
+ *
+ * The caller must have allocated sufficient memory for the @oname string.
+ *
+ * Return: 0 on success, -errno on failure
  */
 int fscrypt_fname_usr_to_disk(struct inode *inode,
 			const struct qstr *iname,
@@ -336,7 +339,7 @@ int fscrypt_fname_usr_to_disk(struct inode *inode,
 		oname->name[0] = '.';
 		oname->name[iname->len - 1] = '.';
 		oname->len = iname->len;
-		return oname->len;
+		return 0;
 	}
 	if (inode->i_crypt_info)
 		return fname_encrypt(inode, iname, oname);
@@ -370,10 +373,10 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 	if (dir->i_crypt_info) {
 		ret = fscrypt_fname_alloc_buffer(dir, iname->len,
 							&fname->crypto_buf);
-		if (ret < 0)
+		if (ret)
 			return ret;
 		ret = fname_encrypt(dir, iname, &fname->crypto_buf);
-		if (ret < 0)
+		if (ret)
 			goto errout;
 		fname->disk_name.name = fname->crypto_buf.name;
 		fname->disk_name.len = fname->crypto_buf.len;
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 7be4f4312..6a7ee212e 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -75,10 +75,8 @@ static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
 		res = ecr.res;
 	}
 out:
-	if (req)
-		ablkcipher_request_free(req);
-	if (tfm)
-		crypto_free_ablkcipher(tfm);
+	ablkcipher_request_free(req);
+	crypto_free_ablkcipher(tfm);
 	return res;
 }
 
@@ -143,13 +141,44 @@ out:
 	return res;
 }
 
+static int determine_cipher_type(struct fscrypt_info *ci, struct inode *inode,
+				 const char **cipher_str_ret, int *keysize_ret)
+{
+	if (S_ISREG(inode->i_mode)) {
+		if (ci->ci_data_mode == FS_ENCRYPTION_MODE_AES_256_XTS) {
+			*cipher_str_ret = "xts(aes)";
+			*keysize_ret = FS_AES_256_XTS_KEY_SIZE;
+			return 0;
+		}
+		pr_warn_once("fscrypto: unsupported contents encryption mode "
+			     "%d for inode %lu\n",
+			     ci->ci_data_mode, inode->i_ino);
+		return -ENOKEY;
+	}
+
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
+		if (ci->ci_filename_mode == FS_ENCRYPTION_MODE_AES_256_CTS) {
+			*cipher_str_ret = "cts(cbc(aes))";
+			*keysize_ret = FS_AES_256_CTS_KEY_SIZE;
+			return 0;
+		}
+		pr_warn_once("fscrypto: unsupported filenames encryption mode "
+			     "%d for inode %lu\n",
+			     ci->ci_filename_mode, inode->i_ino);
+		return -ENOKEY;
+	}
+
+	pr_warn_once("fscrypto: unsupported file type %d for inode %lu\n",
+		     (inode->i_mode & S_IFMT), inode->i_ino);
+	return -ENOKEY;
+}
+
 static void put_crypt_info(struct fscrypt_info *ci)
 {
 	if (!ci)
 		return;
 
-	if (ci->ci_keyring_key)
-		key_put(ci->ci_keyring_key);
+	key_put(ci->ci_keyring_key);
 	crypto_free_ablkcipher(ci->ci_ctfm);
 	kmem_cache_free(fscrypt_info_cachep, ci);
 }
@@ -160,8 +189,8 @@ int get_crypt_info(struct inode *inode)
 	struct fscrypt_context ctx;
 	struct crypto_ablkcipher *ctfm;
 	const char *cipher_str;
+	int keysize;
 	u8 raw_key[FS_MAX_KEY_SIZE];
-	u8 mode;
 	int res;
 
 	res = fscrypt_initialize();
@@ -184,13 +213,19 @@ retry:
 	if (res < 0) {
 		if (!fscrypt_dummy_context_enabled(inode))
 			return res;
+		ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
 		ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
 		ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
 		ctx.flags = 0;
 	} else if (res != sizeof(ctx)) {
 		return -EINVAL;
 	}
-	res = 0;
+
+	if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
+		return -EINVAL;
+
+	if (ctx.flags & ~FS_POLICY_FLAGS_VALID)
+		return -EINVAL;
 
 	crypt_info = kmem_cache_alloc(fscrypt_info_cachep, GFP_NOFS);
 	if (!crypt_info)
@@ -203,27 +238,11 @@ retry:
 	crypt_info->ci_keyring_key = NULL;
 	memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
 				sizeof(crypt_info->ci_master_key));
-	if (S_ISREG(inode->i_mode))
-		mode = crypt_info->ci_data_mode;
-	else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
-		mode = crypt_info->ci_filename_mode;
-	else
-		BUG();
-
-	switch (mode) {
-	case FS_ENCRYPTION_MODE_AES_256_XTS:
-		cipher_str = "xts(aes)";
-		break;
-	case FS_ENCRYPTION_MODE_AES_256_CTS:
-		cipher_str = "cts(cbc(aes))";
-		break;
-	default:
-		printk_once(KERN_WARNING
-			    "%s: unsupported key mode %d (ino %u)\n",
-			    __func__, mode, (unsigned) inode->i_ino);
-		res = -ENOKEY;
+
+	res = determine_cipher_type(crypt_info, inode, &cipher_str, &keysize);
+	if (res)
 		goto out;
-	}
+
 	if (fscrypt_dummy_context_enabled(inode)) {
 		memset(raw_key, 0x42, FS_AES_256_XTS_KEY_SIZE);
 		goto got_key;
@@ -259,7 +278,7 @@ got_key:
 	crypto_ablkcipher_clear_flags(ctfm, ~0);
 	crypto_tfm_set_flags(crypto_ablkcipher_tfm(ctfm),
 					CRYPTO_TFM_REQ_WEAK_KEY);
-	res = crypto_ablkcipher_setkey(ctfm, raw_key, fscrypt_key_size(mode));
+	res = crypto_ablkcipher_setkey(ctfm, raw_key, keysize);
 	if (res)
 		goto out;
 
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 0f9961eed..07e58dd1c 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 = -EOPNOTSUPP;
 	}
 
-	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);