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authorEric Biggers <ebiggers@google.com>2016-09-16 00:25:55 +0300
committerTheodore Ts'o <tytso@mit.edu>2016-09-16 00:25:55 +0300
commitef1eb3aa50930f026135085cd160b1212cdfe817 (patch)
tree12ed99fd9e7dc658b0e1bb0bc78e2ad0bb887dca /fs/crypto
parent53fd7550ec40571e26f730a0d3fc0a5dd93ecda2 (diff)
downloadlinux-ef1eb3aa50930f026135085cd160b1212cdfe817.tar.xz
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 <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Andreas Dilger <adilger@dilger.ca> Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/crypto')
-rw-r--r--fs/crypto/fname.c56
1 files changed, 32 insertions, 24 deletions
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;