fscrypt: Replace 1-element array with flexible array

1-element arrays are deprecated and are being replaced with C99
flexible arrays[1].

As sizes were being calculated with the extra byte intentionally,
propagate the difference so there is no change in binary output.

[1] https://github.com/KSPP/linux/issues/79

Cc: Eric Biggers <ebiggers@kernel.org>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: linux-fscrypt@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230523165458.gonna.580-kees@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Kees Cook 2023-05-23 09:55:02 -07:00 committed by Eric Biggers
parent 44c026a73b
commit d617ef039f
2 changed files with 6 additions and 6 deletions

View File

@ -171,7 +171,7 @@ fscrypt_policy_flags(const union fscrypt_policy *policy)
*/
struct fscrypt_symlink_data {
__le16 len;
char encrypted_path[1];
char encrypted_path[];
} __packed;
/**

View File

@ -255,10 +255,10 @@ int fscrypt_prepare_symlink(struct inode *dir, const char *target,
* for now since filesystems will assume it is there and subtract it.
*/
if (!__fscrypt_fname_encrypted_size(policy, len,
max_len - sizeof(struct fscrypt_symlink_data),
max_len - sizeof(struct fscrypt_symlink_data) - 1,
&disk_link->len))
return -ENAMETOOLONG;
disk_link->len += sizeof(struct fscrypt_symlink_data);
disk_link->len += sizeof(struct fscrypt_symlink_data) + 1;
disk_link->name = NULL;
return 0;
@ -289,7 +289,7 @@ int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
if (!sd)
return -ENOMEM;
}
ciphertext_len = disk_link->len - sizeof(*sd);
ciphertext_len = disk_link->len - sizeof(*sd) - 1;
sd->len = cpu_to_le16(ciphertext_len);
err = fscrypt_fname_encrypt(inode, &iname, sd->encrypted_path,
@ -367,7 +367,7 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
* the ciphertext length, even though this is redundant with i_size.
*/
if (max_size < sizeof(*sd))
if (max_size < sizeof(*sd) + 1)
return ERR_PTR(-EUCLEAN);
sd = caddr;
cstr.name = (unsigned char *)sd->encrypted_path;
@ -376,7 +376,7 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
if (cstr.len == 0)
return ERR_PTR(-EUCLEAN);
if (cstr.len + sizeof(*sd) - 1 > max_size)
if (cstr.len + sizeof(*sd) > max_size)
return ERR_PTR(-EUCLEAN);
err = fscrypt_fname_alloc_buffer(cstr.len, &pstr);