Commit d617ef03 authored by Kees Cook's avatar Kees Cook Committed by Eric Biggers
Browse files

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: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230523165458.gonna.580-kees@kernel.org


Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent 44c026a7

fs/crypto/fscrypt_private.h

+1 −1
Original line number Diff line number Diff line
@@ -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;



/**

fs/crypto/hooks.c

+5 −5
Original line number Diff line number Diff line
@@ -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);