Commit ef1eb3aa authored by Eric Biggers's avatar Eric Biggers Committed by Theodore Ts'o
Browse files

fscrypto: make filename crypto functions return 0 on success 



Several filename crypto functions: fname_decrypt(),
fscrypt_fname_disk_to_usr(), and fscrypt_fname_usr_to_disk(), returned
the output length on success or -errno on failure.  However, the output
length was redundant with the value written to 'oname->len'.  It is also
potentially error-prone to make callers have to check for '< 0' instead
of '!= 0'.

Therefore, make these functions return 0 instead of a length, and make
the callers who cared about the return value being a length use
'oname->len' instead.  For consistency also make other callers check for
a nonzero result rather than a negative result.

This change also fixes the inconsistency of fname_encrypt() actually
already returning 0 on success, not a length like the other filename
crypto functions and as documented in its function comment.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarAndreas Dilger <adilger@dilger.ca>
Acked-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 53fd7550

fs/crypto/fname.c

+32 −24
Original line number Diff line number Diff line
@@ -35,11 +35,11 @@ static void fname_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)
@@ -105,20 +105,22 @@ static int fname_encrypt(struct inode *inode, 
	}

	kfree(alloc_buf);

	skcipher_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,
@@ -168,7 +170,7 @@ static int fname_decrypt(struct inode *inode, 
	}



	oname->len = strnlen(oname->name, iname->len);

	return oname->len;

	return 0;

}



static const char *lookup_table =
@@ -279,6 +281,10 @@ 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,
@@ -287,13 +293,12 @@ 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)
@@ -303,9 +308,9 @@ 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);
@@ -315,15 +320,18 @@ 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,
@@ -333,7 +341,7 @@ 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);
@@ -367,10 +375,10 @@ 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;

fs/ext4/dir.c

+3 −2
Original line number Diff line number Diff line
@@ -260,11 +260,12 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx) 
					/* Directory is encrypted */

					err = fscrypt_fname_disk_to_usr(inode,

						0, 0, &de_name, &fstr);

					de_name = fstr;

					fstr.len = save_len;

					if (err < 0)

					if (err)

						goto errout;

					if (!dir_emit(ctx,

					    fstr.name, err,

					    de_name.name, de_name.len,

					    le32_to_cpu(de->inode),

					    get_dtype(sb, de->file_type)))

						goto done;

fs/ext4/namei.c

+4 −4
Original line number Diff line number Diff line
@@ -639,7 +639,7 @@ static struct stats dx_show_leaf(struct inode *dir, 
					res = fscrypt_fname_alloc_buffer(

						dir, len,

						&fname_crypto_str);

					if (res < 0)

					if (res)

						printk(KERN_WARNING "Error "

							"allocating crypto "

							"buffer--skipping "
@@ -647,7 +647,7 @@ static struct stats dx_show_leaf(struct inode *dir, 
					res = fscrypt_fname_disk_to_usr(dir,

						0, 0, &de_name,

						&fname_crypto_str);

					if (res < 0) {

					if (res) {

						printk(KERN_WARNING "Error "

							"converting filename "

							"from disk to usr"
@@ -1011,7 +1011,7 @@ static int htree_dirblock_to_tree(struct file *dir_file, 
			err = fscrypt_fname_disk_to_usr(dir, hinfo->hash,

					hinfo->minor_hash, &de_name,

					&fname_crypto_str);

			if (err < 0) {

			if (err) {

				count = err;

				goto errout;

			}
@@ -3144,7 +3144,7 @@ static int ext4_symlink(struct inode *dir, 
		istr.name = (const unsigned char *) symname;

		istr.len = len;

		err = fscrypt_fname_usr_to_disk(inode, &istr, &ostr);

		if (err < 0)

		if (err)

			goto err_drop_inode;

		sd->len = cpu_to_le16(ostr.len);

		disk_link.name = (char *) sd;

fs/ext4/symlink.c

+2 −3
Original line number Diff line number Diff line
@@ -68,12 +68,11 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry, 
	paddr = pstr.name;



	res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);

	if (res < 0)

	if (res)

		goto errout;



	/* Null-terminate the name */

	if (res <= pstr.len)

		paddr[res] = '\0';

	paddr[pstr.len] = '\0';

	if (cpage)

		put_page(cpage);

	set_delayed_call(done, kfree_link, paddr);

fs/f2fs/dir.c

+3 −3
Original line number Diff line number Diff line
@@ -786,7 +786,7 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, 


		if (f2fs_encrypted_inode(d->inode)) {

			int save_len = fstr->len;

			int ret;

			int err;



			de_name.name = f2fs_kmalloc(de_name.len, GFP_NOFS);

			if (!de_name.name)
@@ -794,11 +794,11 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, 


			memcpy(de_name.name, d->filename[bit_pos], de_name.len);



			ret = fscrypt_fname_disk_to_usr(d->inode,

			err = fscrypt_fname_disk_to_usr(d->inode,

						(u32)de->hash_code, 0,

						&de_name, fstr);

			kfree(de_name.name);

			if (ret < 0)

			if (err)

				return true;



			de_name = *fstr;

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