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fscrypt: make "#define fscrypt_policy" user-only

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The fscrypt UAPI header defines fscrypt_policy to fscrypt_policy_v1,
for source compatibility with old userspace programs.

Internally, the kernel doesn't want that compatibility definition.
Instead, fscrypt_private.h #undefs it and re-defines it to a union.

That works for now.  However, in order to add
fscrypt_operations::get_dummy_policy(), we'll need to forward declare
'union fscrypt_policy' in include/linux/fscrypt.h.  That would cause
build errors because "fscrypt_policy" is used in ioctl numbers.

To avoid this, modify the UAPI header to make the fscrypt_policy
compatibility definition conditional on !__KERNEL__, and make the ioctls
use fscrypt_policy_v1 instead of fscrypt_policy.

Note that this doesn't change the actual ioctl numbers.

Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-11-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2020-09-16 21:11:33 -07:00
parent 9dad5feb49
commit c7f0207b61
2 changed files with 3 additions and 4 deletions
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1
fs/crypto/fscrypt_private.h
View File

@ -97,7 +97,6 @@ static inline const u8 *fscrypt_context_nonce(const union fscrypt_context *ctx)
return NULL;
}
#undef fscrypt_policy
union fscrypt_policy {
u8 version;
struct fscrypt_policy_v1 v1;

6
include/uapi/linux/fscrypt.h
View File

@ -45,7 +45,6 @@ struct fscrypt_policy_v1 {
__u8 flags;
__u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
};
#define fscrypt_policy fscrypt_policy_v1
/*
* Process-subscribed "logon" key description prefix and payload format.
@ -156,9 +155,9 @@ struct fscrypt_get_key_status_arg {
__u32 __out_reserved[13];
};
#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy)
#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy_v1)
#define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16])
#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy)
#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy_v1)
#define FS_IOC_GET_ENCRYPTION_POLICY_EX _IOWR('f', 22, __u8[9]) /* size + version */
#define FS_IOC_ADD_ENCRYPTION_KEY _IOWR('f', 23, struct fscrypt_add_key_arg)
#define FS_IOC_REMOVE_ENCRYPTION_KEY _IOWR('f', 24, struct fscrypt_remove_key_arg)
@ -170,6 +169,7 @@ struct fscrypt_get_key_status_arg {
/* old names; don't add anything new here! */
#ifndef __KERNEL__
#define fscrypt_policy fscrypt_policy_v1
#define FS_KEY_DESCRIPTOR_SIZE FSCRYPT_KEY_DESCRIPTOR_SIZE
#define FS_POLICY_FLAGS_PAD_4 FSCRYPT_POLICY_FLAGS_PAD_4
#define FS_POLICY_FLAGS_PAD_8 FSCRYPT_POLICY_FLAGS_PAD_8