From: Michael Halcrow via Linux-f2fs-devel Subject: Re: [RFC PATCH 02/25] fscrypt: use FSCRYPT_ prefix for uapi constants Date: Fri, 27 Oct 2017 11:02:57 -0700 Message-ID: <20171027180257.GB10611@google.com> References: <20171023214058.128121-1-ebiggers3@gmail.com> <20171023214058.128121-3-ebiggers3@gmail.com> Reply-To: Michael Halcrow Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Ryo Hashimoto , Gwendal Grignou , "Theodore Y . Ts'o" , Eric Biggers , linux-api@vger.kernel.org, Nick Desaulniers , linux-f2fs-devel@lists.sourceforge.net, linux-fscrypt@vger.kernel.org, keyrings@vger.kernel.org, linux-mtd@lists.infradead.org, Sarthak Kukreti , linux-fsdevel@vger.kernel.org, Jaegeuk Kim , linux-ext4@vger.kernel.org To: Eric Biggers Return-path: Content-Disposition: inline In-Reply-To: <20171023214058.128121-3-ebiggers3@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net List-Id: linux-ext4.vger.kernel.org On Mon, Oct 23, 2017 at 02:40:35PM -0700, Eric Biggers wrote: > From: Eric Biggers > > Prefix all filesystem encryption UAPI constants except the ioctl numbers > with "FSCRYPT_" rather than with "FS_". This namespaces the constants > more appropriately and makes it clear that they are related specifically > to the filesystem encryption feature, and to the 'fscrypt_*' structures. > With some of the old names like "FS_POLICY_FLAGS_VALID", it was not > immediately clear that the constant had anything to do with encryption. > > This is also useful because we'll be adding more encryption-related > constants, e.g. for the policy version, and we'd otherwise have to > choose whether to use unclear names like FS_POLICY_VERSION_* or > inconsistent names like FS_ENCRYPTION_POLICY_VERSION_*. > > For source compatibility with older userspace programs, keep the old > names defined as aliases to the new ones. (It's debatable whether we > really need this, though; the filesystem encryption API is new enough > that most if not all programs that are using it have to declare it > themselves anyway.) > > Signed-off-by: Eric Biggers Reviewed-by: Michael Halcrow > --- > Documentation/filesystems/fscrypt.rst | 14 ++++----- > include/uapi/linux/fscrypt.h | 59 ++++++++++++++++++++++++----------- > 2 files changed, 47 insertions(+), 26 deletions(-) > > diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst > index 776ddc655f79..f12956f3f1f8 100644 > --- a/Documentation/filesystems/fscrypt.rst > +++ b/Documentation/filesystems/fscrypt.rst > @@ -251,14 +251,14 @@ empty directory or verifies that a directory or regular file already > has the specified encryption policy. It takes in a pointer to a > :c:type:`struct fscrypt_policy`, defined as follows:: > > - #define FS_KEY_DESCRIPTOR_SIZE 8 > + #define FSCRYPT_KEY_DESCRIPTOR_SIZE 8 > > struct fscrypt_policy { > __u8 version; > __u8 contents_encryption_mode; > __u8 filenames_encryption_mode; > __u8 flags; > - __u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; > + __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; > }; > > This structure must be initialized as follows: > @@ -274,7 +274,7 @@ This structure must be initialized as follows: > > - ``flags`` must be set to a value from ```` which > identifies the amount of NUL-padding to use when encrypting > - filenames. If unsure, use FS_POLICY_FLAGS_PAD_32 (0x3). > + filenames. If unsure, use FSCRYPT_POLICY_FLAGS_PAD_32 (0x3). > > - ``master_key_descriptor`` specifies how to find the master key in > the keyring; see `Adding keys`_. It is up to userspace to choose a > @@ -374,11 +374,11 @@ followed by the 16-character lower case hex representation of the > ``master_key_descriptor`` that was set in the encryption policy. The > key payload must conform to the following structure:: > > - #define FS_MAX_KEY_SIZE 64 > + #define FSCRYPT_MAX_KEY_SIZE 64 > > struct fscrypt_key { > u32 mode; > - u8 raw[FS_MAX_KEY_SIZE]; > + u8 raw[FSCRYPT_MAX_KEY_SIZE]; > u32 size; > }; > > @@ -533,7 +533,7 @@ much confusion if an encryption policy were to be added to or removed > from anything other than an empty directory.) The struct is defined > as follows:: > > - #define FS_KEY_DESCRIPTOR_SIZE 8 > + #define FSCRYPT_KEY_DESCRIPTOR_SIZE 8 > #define FS_KEY_DERIVATION_NONCE_SIZE 16 > > struct fscrypt_context { > @@ -541,7 +541,7 @@ as follows:: > u8 contents_encryption_mode; > u8 filenames_encryption_mode; > u8 flags; > - u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; > + u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; > u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; > }; > > diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h > index c09209fc42ea..26c381a40279 100644 > --- a/include/uapi/linux/fscrypt.h > +++ b/include/uapi/linux/fscrypt.h > @@ -7,30 +7,31 @@ > * File system encryption support > */ > /* Policy provided via an ioctl on the topmost directory */ > -#define FS_KEY_DESCRIPTOR_SIZE 8 > +#define FSCRYPT_KEY_DESCRIPTOR_SIZE 8 > > -#define FS_POLICY_FLAGS_PAD_4 0x00 > -#define FS_POLICY_FLAGS_PAD_8 0x01 > -#define FS_POLICY_FLAGS_PAD_16 0x02 > -#define FS_POLICY_FLAGS_PAD_32 0x03 > -#define FS_POLICY_FLAGS_PAD_MASK 0x03 > -#define FS_POLICY_FLAGS_VALID 0x03 > +/* Encryption policy flags */ > +#define FSCRYPT_POLICY_FLAGS_PAD_4 0x00 > +#define FSCRYPT_POLICY_FLAGS_PAD_8 0x01 > +#define FSCRYPT_POLICY_FLAGS_PAD_16 0x02 > +#define FSCRYPT_POLICY_FLAGS_PAD_32 0x03 > +#define FSCRYPT_POLICY_FLAGS_PAD_MASK 0x03 > +#define FSCRYPT_POLICY_FLAGS_VALID 0x03 > > /* Encryption algorithms */ > -#define FS_ENCRYPTION_MODE_INVALID 0 > -#define FS_ENCRYPTION_MODE_AES_256_XTS 1 > -#define FS_ENCRYPTION_MODE_AES_256_GCM 2 > -#define FS_ENCRYPTION_MODE_AES_256_CBC 3 > -#define FS_ENCRYPTION_MODE_AES_256_CTS 4 > -#define FS_ENCRYPTION_MODE_AES_128_CBC 5 > -#define FS_ENCRYPTION_MODE_AES_128_CTS 6 > +#define FSCRYPT_MODE_INVALID 0 > +#define FSCRYPT_MODE_AES_256_XTS 1 > +#define FSCRYPT_MODE_AES_256_GCM 2 > +#define FSCRYPT_MODE_AES_256_CBC 3 > +#define FSCRYPT_MODE_AES_256_CTS 4 > +#define FSCRYPT_MODE_AES_128_CBC 5 > +#define FSCRYPT_MODE_AES_128_CTS 6 > > struct fscrypt_policy { > __u8 version; > __u8 contents_encryption_mode; > __u8 filenames_encryption_mode; > __u8 flags; > - __u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; > + __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; > }; > > #define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy) > @@ -38,16 +39,36 @@ struct fscrypt_policy { > #define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy) > > /* Parameters for passing an encryption key into the kernel keyring */ > -#define FS_KEY_DESC_PREFIX "fscrypt:" > -#define FS_KEY_DESC_PREFIX_SIZE 8 > +#define FSCRYPT_KEY_DESC_PREFIX "fscrypt:" > +#define FSCRYPT_KEY_DESC_PREFIX_SIZE 8 > > /* Structure that userspace passes to the kernel keyring */ > -#define FS_MAX_KEY_SIZE 64 > +#define FSCRYPT_MAX_KEY_SIZE 64 > > struct fscrypt_key { > __u32 mode; > - __u8 raw[FS_MAX_KEY_SIZE]; > + __u8 raw[FSCRYPT_MAX_KEY_SIZE]; > __u32 size; > }; > +/**********************************************************************/ > + > +/* old names; don't add anything new here! */ > +#define FS_POLICY_FLAGS_PAD_4 FSCRYPT_POLICY_FLAGS_PAD_4 > +#define FS_POLICY_FLAGS_PAD_8 FSCRYPT_POLICY_FLAGS_PAD_8 > +#define FS_POLICY_FLAGS_PAD_16 FSCRYPT_POLICY_FLAGS_PAD_16 > +#define FS_POLICY_FLAGS_PAD_32 FSCRYPT_POLICY_FLAGS_PAD_32 > +#define FS_POLICY_FLAGS_PAD_MASK FSCRYPT_POLICY_FLAGS_PAD_MASK > +#define FS_POLICY_FLAGS_VALID FSCRYPT_POLICY_FLAGS_VALID > +#define FS_KEY_DESCRIPTOR_SIZE FSCRYPT_KEY_DESCRIPTOR_SIZE > +#define FS_ENCRYPTION_MODE_INVALID FSCRYPT_MODE_INVALID > +#define FS_ENCRYPTION_MODE_AES_256_XTS FSCRYPT_MODE_AES_256_XTS > +#define FS_ENCRYPTION_MODE_AES_256_GCM FSCRYPT_MODE_AES_256_GCM > +#define FS_ENCRYPTION_MODE_AES_256_CBC FSCRYPT_MODE_AES_256_CBC > +#define FS_ENCRYPTION_MODE_AES_256_CTS FSCRYPT_MODE_AES_256_CTS > +#define FS_ENCRYPTION_MODE_AES_128_CBC FSCRYPT_MODE_AES_128_CBC > +#define FS_ENCRYPTION_MODE_AES_128_CTS FSCRYPT_MODE_AES_128_CTS > +#define FS_KEY_DESC_PREFIX FSCRYPT_KEY_DESC_PREFIX > +#define FS_KEY_DESC_PREFIX_SIZE FSCRYPT_KEY_DESC_PREFIX_SIZE > +#define FS_MAX_KEY_SIZE FSCRYPT_MAX_KEY_SIZE > > #endif /* _UAPI_LINUX_FSCRYPT_H */ > -- > 2.15.0.rc0.271.g36b669edcc-goog > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot