On Tue, Sep 24, 2019 at 05:39:02PM -0500, Eric Sandeen wrote:
> On 9/19/19 7:18 PM, Eric Biggers wrote:
> > From: Eric Biggers <ebiggers@xxxxxxxxxx>
> >
> > Add a 'rm_enckey' command to xfs_io, to provide a command-line interface
> > to the FS_IOC_REMOVE_ENCRYPTION_KEY and
> > FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS ioctls.
> >
> > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> > ---
> > io/encrypt.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++
> > man/man8/xfs_io.8 | 15 ++++++++++
> > 2 files changed, 90 insertions(+)
> >
> > diff --git a/io/encrypt.c b/io/encrypt.c
> > index d38ac595..7531c4ad 100644
> > --- a/io/encrypt.c
> > +++ b/io/encrypt.c
> > @@ -139,6 +139,7 @@ struct fscrypt_get_key_status_arg {
> > static cmdinfo_t get_encpolicy_cmd;
> > static cmdinfo_t set_encpolicy_cmd;
> > static cmdinfo_t add_enckey_cmd;
> > +static cmdinfo_t rm_enckey_cmd;
> >
> > static void
> > get_encpolicy_help(void)
> > @@ -200,6 +201,21 @@ add_enckey_help(void)
> > "\n"));
> > }
> >
> > +static void
> > +rm_enckey_help(void)
> > +{
> > + printf(_(
> > +"\n"
> > +" remove an encryption key from the filesystem\n"
> > +"\n"
> > +" Examples:\n"
> > +" 'rm_enckey 0000111122223333' - remove key for v1 policies w/ given descriptor\n"
> > +" 'rm_enckey 00001111222233334444555566667777' - remove key for v2 policies w/ given identifier\n"
> > +"\n"
> > +" -a -- remove key for all users who have added it (privileged operation)\n"
> > +"\n"));
> > +}
> > +
> > static const struct {
> > __u8 mode;
> > const char *name;
> > @@ -693,6 +709,54 @@ out:
> > return 0;
> > }
> >
> > +static int
> > +rm_enckey_f(int argc, char **argv)
> > +{
> > + int c;
> > + struct fscrypt_remove_key_arg arg;
> > + int ioc = FS_IOC_REMOVE_ENCRYPTION_KEY;
> > +
> > + memset(&arg, 0, sizeof(arg));
> > +
> > + while ((c = getopt(argc, argv, "a")) != EOF) {
> > + switch (c) {
> > + case 'a':
> > + ioc = FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS;
> > + break;
> > + default:
> > + return command_usage(&rm_enckey_cmd);
> > + }
> > + }
> > + argc -= optind;
> > + argv += optind;
> > +
> > + if (argc != 1)
> > + return command_usage(&rm_enckey_cmd);
> > +
> > + if (str2keyspec(argv[0], -1, &arg.key_spec) < 0)
> > + return 0;
> > +
> > + if (ioctl(file->fd, ioc, &arg) != 0) {
> > + fprintf(stderr, "Error removing encryption key: %s\n",
> > + strerror(errno));
> > + exitcode = 1;
> > + return 0;
> > + }
> > + if (arg.removal_status_flags &
> > + FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS) {
> > + printf("Removed user's claim to encryption key with %s %s\n",
> > + keyspectype(&arg.key_spec), keyspec2str(&arg.key_spec));
> > + } else if (arg.removal_status_flags &
> > + FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY) {
> > + printf("Removed encryption key with %s %s, but files still busy\n",
> > + keyspectype(&arg.key_spec), keyspec2str(&arg.key_spec));
> > + } else {
> > + printf("Removed encryption key with %s %s\n",
> > + keyspectype(&arg.key_spec), keyspec2str(&arg.key_spec));
> > + }
> > + return 0;
> > +}
> > +
> > void
> > encrypt_init(void)
> > {
> > @@ -726,7 +790,18 @@ encrypt_init(void)
> > add_enckey_cmd.oneline = _("add an encryption key to the filesystem");
> > add_enckey_cmd.help = add_enckey_help;
> >
> > + rm_enckey_cmd.name = "rm_enckey";
> > + rm_enckey_cmd.cfunc = rm_enckey_f;
> > + rm_enckey_cmd.args = _("keyspec");
>
> can you add "-a" to the args for the shorthelp/args here please?
Will do.
>
> I don't know anything about this stuff. :( Is it to be used as:
>
> rm_enckey -a <keyspec> ?
Yes, -a is just an optional argument. Nothing special.
>
> > + rm_enckey_cmd.argmin = 0;
> > + rm_enckey_cmd.argmax = -1;
>
> I wonder if min/max should be 1/2 but eh, I think you catch wrong counts
> in the function itself, just without the explicit message the built-in
> checkers would give.
Well since there's only one option, we *could* pretend that it's an optional
positional argument, and do argmin=1, argmax=2, and
if (argc == 2) {
if (strcmp(argv[1], "-a") != 0)
return command_usage(&rm_enckey_cmd);
ioc = FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS;
argv++;
}
But all that would need to be changed if/when a second option is added.
IMO it's better to handle it in the standard way.
>
> > + rm_enckey_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
> > + rm_enckey_cmd.oneline =
> > + _("remove an encryption key from the filesystem");
> > + rm_enckey_cmd.help = rm_enckey_help;
> > +
> > add_command(&get_encpolicy_cmd);
> > add_command(&set_encpolicy_cmd);
> > add_command(&add_enckey_cmd);
> > + add_command(&rm_enckey_cmd);
> > }
> > diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> > index 7d6a23fe..a6894778 100644
> > --- a/man/man8/xfs_io.8
> > +++ b/man/man8/xfs_io.8
> > @@ -764,6 +764,21 @@ Otherwise, the key is added as a v2 policy key, and on success the resulting
> > .RE
> > .PD
> > .TP
> > +.BI "rm_enckey " keyspec
>
> show [-a] here as well?
>
Will do.
- Eric
