libzfs: zfs_mount_at(): load key for encryption root if MS_CRYPT

zfs_crypto_load_key() only works on encryption roots,
and zfs mount -la would fail if it encounters a datasets that
is sorted before their encroots.

To trigger:
  truncate -s 40G /tmp/test
  dd if=/dev/urandom of=/tmp/k bs=128 count=1 status=none
  zpool create -O encryption=on -O keylocation=file:///tmp/k \
               -O keyformat=passphrase test /tmp/test
  zfs create -o mountpoint=/a test/a
  zfs create -o mountpoint=/b test/b
  zfs umount test
  zfs unload-key test
  zfs mount -la

The final mount errored out with:
  Key load error: Keys must be loaded for
    encryption root of 'test/a' (test).
  Key load error: Keys must be loaded for
    encryption root of 'test/b' (test).

And only /test was mounted

This technically breaks the libzfs API, but the previous behavior was
decidedly a bug.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #11870 
Closes #11875
This commit is contained in:
наб 2021-04-13 06:26:55 +02:00 committed by GitHub
parent 93f81eb721
commit b3530c4262
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23

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@ -385,6 +385,9 @@ zfs_mount_at(zfs_handle_t *zhp, const char *options, int flags,
struct stat buf;
char mntopts[MNT_LINE_MAX];
char overlay[ZFS_MAXPROPLEN];
char prop_encroot[MAXNAMELEN];
boolean_t is_encroot;
zfs_handle_t *encroot_hp = zhp;
libzfs_handle_t *hdl = zhp->zfs_hdl;
uint64_t keystatus;
int remount = 0, rc;
@ -443,7 +446,27 @@ zfs_mount_at(zfs_handle_t *zhp, const char *options, int flags,
*/
if (keystatus == ZFS_KEYSTATUS_UNAVAILABLE) {
if (flags & MS_CRYPT) {
rc = zfs_crypto_load_key(zhp, B_FALSE, NULL);
rc = zfs_crypto_get_encryption_root(zhp,
&is_encroot, prop_encroot);
if (rc) {
zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
"Failed to get encryption root for "
"'%s'."), zfs_get_name(zhp));
return (rc);
}
if (!is_encroot) {
encroot_hp = zfs_open(hdl, prop_encroot,
ZFS_TYPE_DATASET);
if (encroot_hp == NULL)
return (hdl->libzfs_error);
}
rc = zfs_crypto_load_key(encroot_hp,
B_FALSE, NULL);
if (!is_encroot)
zfs_close(encroot_hp);
if (rc)
return (rc);
} else {