1-element arrays are deprecated, and are being replaced with C99
flexible arrays[1]. In the future, we can add annotations for the
flexible array member "encrypted_path" to have a size determined
by the "len" member.
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@xxxxxxxxxx>
Cc: "Theodore Y. Ts'o" <tytso@xxxxxxx>
Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Cc: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Cc: linux-fscrypt@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
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);
--
2.34.1
|