From d617ef039fb8eec48a3424f79327220e0b7cbff7 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 23 May 2023 09:55:02 -0700 Subject: [PATCH] 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 Cc: "Theodore Y. Ts'o" Cc: Jaegeuk Kim Cc: Gustavo A. R. Silva Cc: linux-fscrypt@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20230523165458.gonna.580-kees@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/fscrypt_private.h | 2 +- fs/crypto/hooks.c | 10 +++++----- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 7ab5a7b7eef8..2d63da48635a 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -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; /** diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 9e786ae66a13..6238dbcadcad 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -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);