On 11/28/16 4:18 PM, Eric Biggers wrote:
> Add set_encpolicy and get_encpolicy commands to xfs_io so that xfstests
> will be able to test filesystem encryption using the actual user API,
> not just hacked in with a mount option. These commands use the common
> "fscrypt" API currently implemented by ext4 and f2fs, but it's also
> under development for ubifs and planned for xfs.
>
> Note that to get encrypted files to actually work, it's also necessary
> to add a key to the kernel keyring. This patch does not add a command
> for this to xfs_io because it's possible to do it using keyctl. keyctl
> can also be used to remove keys, revoke keys, invalidate keys, etc.
>
> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> ---
> io/Makefile | 6 +-
> io/encrypt.c | 303 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> io/init.c | 1 +
> io/io.h | 1 +
> man/man8/xfs_io.8 | 27 +++++
> 5 files changed, 335 insertions(+), 3 deletions(-)
> create mode 100644 io/encrypt.c
>
> diff --git a/io/Makefile b/io/Makefile
> index 1072e74..89cca66 100644
> --- a/io/Makefile
> +++ b/io/Makefile
> @@ -9,9 +9,9 @@ LTCOMMAND = xfs_io
> LSRCFILES = xfs_bmap.sh xfs_freeze.sh xfs_mkfile.sh
> HFILES = init.h io.h
> CFILES = init.c \
> - attr.c bmap.c file.c freeze.c fsync.c getrusage.c imap.c link.c \
> - mmap.c open.c parent.c pread.c prealloc.c pwrite.c seek.c shutdown.c \
> - sync.c truncate.c reflink.c cowextsize.c
> + attr.c bmap.c encrypt.c file.c freeze.c fsync.c getrusage.c imap.c \
> + link.c mmap.c open.c parent.c pread.c prealloc.c pwrite.c seek.c \
> + shutdown.c sync.c truncate.c reflink.c cowextsize.c
>
> LLDLIBS = $(LIBXCMD) $(LIBHANDLE) $(LIBPTHREAD)
> LTDEPENDENCIES = $(LIBXCMD) $(LIBHANDLE)
> diff --git a/io/encrypt.c b/io/encrypt.c
> new file mode 100644
> index 0000000..2006684
> --- /dev/null
> +++ b/io/encrypt.c
> @@ -0,0 +1,303 @@
> +/*
> + * Copyright (c) 2016 Google, Inc. All Rights Reserved.
> + *
> + * Author: Eric Biggers <ebiggers@xxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include "platform_defs.h"
> +#include "command.h"
> +#include "init.h"
> +#include "io.h"
> +
> +#ifndef ARRAY_SIZE
> +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> +#endif
> +
> +/*
> + * We have to define the ioctl structures and constants ourselves because
> + * someone may be compiling xfsprogs with old kernel headers. Also, as of Linux
> + * 4.9, not all the needed definitions are in <linux/fs.h>.
> + */
Ok, but this needs to be guarded, then - or else newer kernel
headers will cause it to fail:
[CC] encrypt.o
encrypt.c:37:8: error: redefinition of ‘struct fscrypt_policy’
struct fscrypt_policy {
^~~~~~~~~~~~~~
In file included from ../include/xfs/linux.h:38:0,
from ../include/xfs.h:37,
from io.h:19,
from encrypt.c:23:
/usr/include/linux/fs.h:257:8: note: originally defined here
struct fscrypt_policy {
^~~~~~~~~~~~~~
../include/buildrules:59: recipe for target 'encrypt.o' failed
> +#define FS_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];
> +} __attribute__((packed));
> +
> +#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy)
> +#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_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
> +
> +#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
> +
> +static cmdinfo_t get_encpolicy_cmd;
> +static cmdinfo_t set_encpolicy_cmd;
> +
> +static void
> +get_encpolicy_help(void)
> +{
> + printf(_(
> +"\n"
> +" display the encryption policy of the currently open file\n"
> +"\n"));
> +}
No need to add this, it ends up just restating the short help:
xfs_io> help get_encpolicy
get_encpolicy -- display the encryption policy of the current file
display the encryption policy of the currently open file
xfs_io>
if you leave out the .help altogether you'll just get the oneline
help, which is enough here.
(random thought, if you call them encpolicy_set and encpolicy_get,
they'll end up next to each other in help output, but *shrug*)
> +static void
> +set_encpolicy_help(void)
> +{
> + printf(_(
> +"\n"
> +" assign an encryption policy to the currently open file\n"
> +"\n"
> +" Examples:\n"
> +" 'set_encpolicy' - assign policy with default key [0000000000000000]\n"
> +" 'set_encpolicy 0000111122223333' - assign policy with specified key\n"
> +"\n"
> +" -c MODE -- contents encryption mode\n"
> +" -n MODE -- filenames encryption mode\n"
> +" -f FLAGS -- policy flags\n"
> +" -v VERSION -- version of policy structure\n"
> +"\n"
> +"MODE can be numeric or one of the following predefined values:\n"
> +" AES-256-XTS, AES-256-CTS, AES-256-GCM, AES-256-CBC\n"
> +"FLAGS and VERSION must be numeric.\n"
> +"\n"
> +"Note that it's only possible to set an encryption policy on an empty\n"
> +"directory. It's then inherited by new files and subdirectories.\n"
> +"\n"));
I think every other long help indents each line by at one space, so for
consistency that would be good here as well - it sets the help text
apart a bit more.
> +}
> +
> +static const struct {
> + __u8 mode;
> + const char *name;
> +} available_modes[] = {
> + {FS_ENCRYPTION_MODE_AES_256_XTS, "AES-256-XTS"},
> + {FS_ENCRYPTION_MODE_AES_256_CTS, "AES-256-CTS"},
> + {FS_ENCRYPTION_MODE_AES_256_GCM, "AES-256-GCM"},
> + {FS_ENCRYPTION_MODE_AES_256_CBC, "AES-256-CBC"},
> +};
> +
> +static int
> +parse_byte_value(const char *arg, __u8 *value_ret)
> +{
> + long value;
> + char *tmp;
> +
> + value = strtol(arg, &tmp, 0);
> + if (value < 0 || value > 255 || tmp == arg || *tmp != '\0')
> + return 1;
> + *value_ret = value;
> + return 0;
> +}
> +
> +static int
> +parse_mode(const char *arg, __u8 *mode_ret)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(available_modes); i++) {
> + if (strcmp(arg, available_modes[i].name) == 0) {
> + *mode_ret = available_modes[i].mode;
> + return 0;
> + }
> + }
> +
> + return parse_byte_value(arg, mode_ret);
> +}
> +
> +static const char *
> +mode2str(__u8 mode)
> +{
> + static char buf[32];
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(available_modes); i++)
> + if (mode == available_modes[i].mode)
> + return available_modes[i].name;
> +
> + sprintf(buf, "0x%02x", mode);
> + return buf;
> +}
> +
> +static const char *
> +keydesc2str(__u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE])
> +{
> + static char buf[2 * FS_KEY_DESCRIPTOR_SIZE + 1];
> + int i;
> +
> + for (i = 0; i < FS_KEY_DESCRIPTOR_SIZE; i++)
> + sprintf(&buf[2 * i], "%02x", master_key_descriptor[i]);
> +
> + return buf;
> +}
> +
> +static int
> +get_encpolicy_f(int argc, char **argv)
> +{
> + struct fscrypt_policy policy;
> +
> + if (ioctl(file->fd, FS_IOC_GET_ENCRYPTION_POLICY, &policy) < 0) {
> + fprintf(stderr, "%s: failed to get encryption policy: %s\n",
> + file->name, strerror(errno));
> + return 1;
Ok, I need to go look at dave's other patch series to give you guidance
on what to return here, or anything else under the foo_f() functions.
see [PATCH 0/6] xfs_io: fix up command iteration - I need to see how dave
wants that all to work now. Prior to that, anyway, most commands returned
0 even on an error, and possibly set exitcode = 1, but I have to see what
that patchset does.
> + }
> +
> + printf("Encryption policy for %s:\n", file->name);
> + printf("\tPolicy version: %u\n", policy.version);
> + printf("\tMaster key descriptor: %s\n",
> + keydesc2str(policy.master_key_descriptor));
> + printf("\tContents encryption mode: %u (%s)\n",
> + policy.contents_encryption_mode,
> + mode2str(policy.contents_encryption_mode));
> + printf("\tFilenames encryption mode: %u (%s)\n",
> + policy.filenames_encryption_mode,
> + mode2str(policy.filenames_encryption_mode));
> + printf("\tFlags: 0x%02x\n", policy.flags);
> + return 0;
> +}
> +
> +static int
> +set_encpolicy_f(int argc, char **argv)
> +{
> + int c;
> + struct fscrypt_policy policy;
> +
> + /* Initialize the policy structure with default values */
> + memset(&policy, 0, sizeof(policy));
> + policy.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
> + policy.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
> + policy.flags = FS_POLICY_FLAGS_PAD_16;
> +
> + /* Parse options */
> + while ((c = getopt(argc, argv, "c:n:f:v:")) != EOF) {
> + switch (c) {
> + case 'c':
> + if (parse_mode(optarg,
> + &policy.contents_encryption_mode)) {
> + fprintf(stderr, "invalid contents encryption "
> + "mode: %s\n", optarg);
> + return 1;
> + }
> + break;
> + case 'n':
> + if (parse_mode(optarg,
> + &policy.filenames_encryption_mode)) {
> + fprintf(stderr, "invalid filenames encryption "
> + "mode: %s\n", optarg);
> + return 1;
> + }
> + break;
> + case 'f':
> + if (parse_byte_value(optarg, &policy.flags)) {
> + fprintf(stderr, "invalid flags: %s\n", optarg);
> + return 1;
> + }
> + break;
> + case 'v':
> + if (parse_byte_value(optarg, &policy.version)) {
> + fprintf(stderr, "invalid policy version: %s\n",
> + optarg);
> + return 1;
> + }
> + break;
> + default:
> + return command_usage(&set_encpolicy_cmd);
> + }
> + }
> + argc -= optind;
> + argv += optind;
> +
> + if (argc > 1)
> + return command_usage(&set_encpolicy_cmd);
> +
> + /* Parse key descriptor if specified */
> + if (argc > 0) {
> + const char *keydesc = argv[0];
> + char *tmp;
> + unsigned long long x;
> + int i;
> +
> + if (strlen(keydesc) != FS_KEY_DESCRIPTOR_SIZE * 2) {
> + fprintf(stderr, "invalid key descriptor: %s\n",
> + keydesc);
> + return 1;
> + }
> +
> + x = strtoull(keydesc, &tmp, 16);
> + if (tmp == keydesc || *tmp != '\0') {
> + fprintf(stderr, "invalid key descriptor: %s\n",
> + keydesc);
> + return 1;
> + }
> +
> + for (i = 0; i < FS_KEY_DESCRIPTOR_SIZE; i++) {
> + policy.master_key_descriptor[i] = x >> 56;
> + x <<= 8;
> + }
> + }
> +
> + /* Set the encryption policy */
> + if (ioctl(file->fd, FS_IOC_SET_ENCRYPTION_POLICY, &policy) < 0) {
> + fprintf(stderr, "%s: failed to set encryption policy: %s\n",
> + file->name, strerror(errno));
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +void
> +encrypt_init(void)
> +{
> + get_encpolicy_cmd.name = "get_encpolicy";
> + get_encpolicy_cmd.cfunc = get_encpolicy_f;
> + get_encpolicy_cmd.argmin = 0;
> + get_encpolicy_cmd.argmax = 0;
> + get_encpolicy_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
> + get_encpolicy_cmd.oneline =
> + _("display the encryption policy of the current file");
> + get_encpolicy_cmd.help = get_encpolicy_help;
just drop that, since it's the same as the oneline.
-Eric
> +
> + set_encpolicy_cmd.name = "set_encpolicy";
> + set_encpolicy_cmd.cfunc = set_encpolicy_f;
> + set_encpolicy_cmd.args =
> + _("[-c mode] [-n mode] [-f flags] [-v version] [keydesc]");
> + set_encpolicy_cmd.argmin = 0;
> + set_encpolicy_cmd.argmax = -1;
> + set_encpolicy_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
> + set_encpolicy_cmd.oneline =
> + _("assign an encryption policy to the current file");
> + set_encpolicy_cmd.help = set_encpolicy_help;
> +
> + add_command(&get_encpolicy_cmd);
> + add_command(&set_encpolicy_cmd);
> +}
> diff --git a/io/init.c b/io/init.c
> index a9191cf..ee7683e 100644
> --- a/io/init.c
> +++ b/io/init.c
> @@ -59,6 +59,7 @@ init_commands(void)
> attr_init();
> bmap_init();
> copy_range_init();
> + encrypt_init();
> fadvise_init();
> file_init();
> flink_init();
> diff --git a/io/io.h b/io/io.h
> index 5d21314..d257daa 100644
> --- a/io/io.h
> +++ b/io/io.h
> @@ -94,6 +94,7 @@ extern void dump_buffer(off64_t, ssize_t);
>
> extern void attr_init(void);
> extern void bmap_init(void);
> +extern void encrypt_init(void);
> extern void file_init(void);
> extern void flink_init(void);
> extern void freeze_init(void);
> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> index 885df7f..27008de 100644
> --- a/man/man8/xfs_io.8
> +++ b/man/man8/xfs_io.8
> @@ -890,6 +890,33 @@ verbose output will be printed.
> .IP
> .B [NOTE: Not currently operational on Linux.]
> .PD
> +.TP
> +.BI "set_encpolicy [ \-c " mode " ] [ \-n " mode " ] [ \-f " flags " ] [ \-v " version " ] [ " keydesc " ]
> +On filesystems that support encryption, assign an encryption policy to the
> +current file.
> +.I keydesc
> +is a 16-byte hex string which identifies the encryption key to use.
> +If not specified, a "default" key descriptor of all 0's will be used.
> +.RS 1.0i
> +.PD 0
> +.TP 0.4i
> +.BI \-c " mode
> +contents encryption mode (e.g. AES-256-XTS)
> +.TP
> +.BI \-n " mode
> +filenames encryption mode (e.g. AES-256-CTS)
> +.TP
> +.BI \-f " flags
> +policy flags (numeric)
> +.TP
> +.BI \-v " version
> +version of policy structure (numeric)
> +.RE
> +.PD
> +.TP
> +.BR get_encpolicy
> +On filesystems that support encryption, display the encryption policy of the
> +current file.
>
> .SH SEE ALSO
> .BR mkfs.xfs (8),
>
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