From ef1eb3aa50930f026135085cd160b1212cdfe817 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 15 Sep 2016 17:25:55 -0400 Subject: 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: Eric Biggers Signed-off-by: Theodore Ts'o Reviewed-by: Andreas Dilger Acked-by: Jaegeuk Kim --- fs/crypto/fname.c | 56 +++++++++++++++++++++++++++++++------------------------ 1 file changed, 32 insertions(+), 24 deletions(-) (limited to 'fs/crypto') diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 6bbc3b1859e1..90697c70c23b 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -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; -- cgit v1.2.3