Fix UTF-16 result handling for efibootmgrstable/zed

The tl;dr is that UEFI NVRAM is in encoded
in UTF-16, and when we run the efibootmgr command,
we can get unicode characters back.

Except we previously were forcing everything to be
treated as UTF-8 due to the way oslo.concurrency's
processutils module works.

This could be observed with UTF character 0x00FF
which raises up a nice exception when we try to
decode it.

Anyhow! while fixing handling of this, we discovered
we could get basically the cruft out of the NVRAM,
by getting what was most likey a truncated string
out of our own test VMs. As such, we need to also
permit decoding to be tollerant of failures.
This could be binary data or as simple as flipped
bits which get interpretted invalid characters.
As such, we have introduced such data into one of our
tests involving UEFI record de-duplication.

Closes-Bug: 2015602
Change-Id: I006535bf124379ed65443c7b283bc99ecc95568b
(cherry picked from commit 76accfb880474445a5dcb07825889123b3dd0237)

4 files changed, 91 insertions, 63 deletions

diff --git a/ironic_python_agent/efi_utils.py b/ironic_python_agent/efi_utils.py
index 48e643d3..6fc8dff1 100644
--- a/ironic_python_agent/efi_utils.py
+++ b/ironic_python_agent/efi_utils.py
@@ -275,8 +275,15 @@ def get_boot_records():
 
     :return: an iterator yielding pairs (boot number, boot record).
     """
-    efi_output = utils.execute('efibootmgr', '-v')
-    for line in efi_output[0].split('\n'):
+    # Invokes binary=True so we get a bytestream back.
+    efi_output = utils.execute('efibootmgr', '-v', binary=True)
+    # Bytes must be decoded before regex can be run and
+    # matching to work as intended.
+    # Also ignore errors on decoding, as we can basically get
+    # garbage out of the nvram record, this way we don't fail
+    # hard on unrelated records.
+    cmd_output = efi_output[0].decode('utf-16', errors='ignore')
+    for line in cmd_output.split('\n'):
         match = _ENTRY_LABEL.match(line)
         if match is not None:
             yield (match[1], match[2])
@@ -293,7 +300,7 @@ def add_boot_record(device, efi_partition, loader, label):
     # https://linux.die.net/man/8/efibootmgr
     utils.execute('efibootmgr', '-v', '-c', '-d', device,
                   '-p', str(efi_partition), '-w', '-L', label,
-                  '-l', loader)
+                  '-l', loader, binary=True)
 
 
 def remove_boot_record(boot_num):
@@ -301,7 +308,7 @@ def remove_boot_record(boot_num):
 
     :param boot_num: the number of the boot record
     """
-    utils.execute('efibootmgr', '-b', boot_num, '-B')
+    utils.execute('efibootmgr', '-b', boot_num, '-B', binary=True)
 
 
 def _run_efibootmgr(valid_efi_bootloaders, device, efi_partition,
diff --git a/ironic_python_agent/tests/unit/extensions/test_image.py b/ironic_python_agent/tests/unit/extensions/test_image.py
index e488b74f..32f4addb 100644
--- a/ironic_python_agent/tests/unit/extensions/test_image.py
+++ b/ironic_python_agent/tests/unit/extensions/test_image.py
@@ -32,6 +32,9 @@ from ironic_python_agent.tests.unit import base
 from ironic_python_agent.tests.unit.samples import hardware_samples as hws
 
 
+EFI_RESULT = ''.encode('utf-16')
+
+
 @mock.patch.object(hardware, 'dispatch_to_managers', autospec=True)
 @mock.patch.object(ilib_utils, 'execute', autospec=True)
 @mock.patch.object(tempfile, 'mkdtemp', lambda *_: '/tmp/fake-dir')
@@ -231,7 +234,7 @@ class TestImageExtension(base.IronicAgentTest):
 
         mock_execute.side_effect = iter([('', ''), ('', ''),
                                          ('', ''), ('', ''),
-                                         ('', ''), ('', ''),
+                                         (EFI_RESULT, ''), (EFI_RESULT, ''),
                                          ('', ''), ('', '')])
 
         expected = [mock.call('efibootmgr', '--version'),
@@ -240,11 +243,11 @@ class TestImageExtension(base.IronicAgentTest):
                     mock.call('udevadm', 'settle'),
                     mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -279,7 +282,7 @@ class TestImageExtension(base.IronicAgentTest):
         mock_efi_bl.return_value = ['EFI/BOOT/BOOTX64.EFI']
         mock_execute.side_effect = iter([('', ''), ('', ''),
                                          ('', ''), ('', ''),
-                                         ('', ''), ('', ''),
+                                         (EFI_RESULT, ''), (EFI_RESULT, ''),
                                          ('', ''), ('', '')])
 
         expected = [mock.call('efibootmgr', '--version'),
@@ -288,11 +291,11 @@ class TestImageExtension(base.IronicAgentTest):
                     mock.call('udevadm', 'settle'),
                     mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -333,10 +336,11 @@ Boot0000 ironic1 HD(1,GPT,4f3c6294-bf9b-4208-9808-be45dfc34b5c)File(\EFI\Boot\BO
 Boot0001 ironic2 HD(1,GPT,4f3c6294-bf9b-4208-9808-111111111112)File(\EFI\Boot\BOOTX64.EFI)
 Boot0002 VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
 """  # noqa This is a giant literal string for testing.
+        stdout_msg = stdout_msg.encode('utf-16')
         mock_execute.side_effect = iter([('', ''), ('', ''),
                                          ('', ''), ('', ''),
-                                         (stdout_msg, ''), ('', ''),
-                                         ('', ''), ('', ''),
+                                         (stdout_msg, ''), (EFI_RESULT, ''),
+                                         (EFI_RESULT, ''), (EFI_RESULT, ''),
                                          ('', ''), ('', '')])
 
         expected = [mock.call('efibootmgr', '--version'),
@@ -345,12 +349,12 @@ Boot0002 VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
                     mock.call('udevadm', 'settle'),
                     mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
-                    mock.call('efibootmgr', '-b', '0000', '-B'),
+                    mock.call('efibootmgr', '-v', binary=True),
+                    mock.call('efibootmgr', '-b', '0000', '-B', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -396,6 +400,7 @@ Boot0002* Hard Disk     VenHw(1fad3248-0000-7950-2166-a1e506fdb83a,01000000)..GO
 Boot0003* Network       VenHw(1fad3248-0000-7950-2166-a1e506fdb83a,05000000)..GO..NO............U.E.F.I.:. . . .S.L.O.T.2. .(.2.F./.0./.0.). .P.X.E. .I.P.4. . .Q.L.o.g.i.c. .Q.L.4.1.2.6.2. .P.C.I.e. .2.5.G.b. .2.-.P.o.r.t. .S.F.P.2.8. .E.t.h.e.r.n.e.t. .A.d.a.p.t.e.r. .-. .P.X.E........A....................%.4..Z...............................................................Gd-.;.A..MQ..L.P.X.E. .I.P.4. .Q.L.o.g.i.c. .Q.L.4.1.2.6.2. .P.C.I.e. .2.5.G.b. .2.-.P.o.r.t. .S.F.P.2.8. .E.t.h.e.r.n.e.t. .A.d.a.p.t.e.r. .-. .P.X.E.......BO..NO............U.E.F.I.:. . . .S.L.O.T.1. .(.3.0./.0./.0.). .P.X.E. .I.P.4. . .Q.L.o.g.i.c. .Q.L.4.1.2.6.2. .P.C.I.e. .2.5.G.b. .2.-.P.o.r.t. .S.F.P.2.8. .E.t.h.e.r.n.e.t. .A.d.a.p.t.e.r. .-.
 Boot0004* ironic1      HD(1,GPT,55db8d03-c8f6-4a5b-9155-790dddc348fa,0x800,0x64000)/File(\EFI\boot\shimx64.efi)
 """  # noqa This is a giant literal string for testing.
+        stdout_msg = stdout_msg.encode('utf-16')
         mock_execute.side_effect = iter([('', ''), ('', ''),
                                          ('', ''), ('', ''),
                                          (stdout_msg, ''), ('', ''),
@@ -407,13 +412,13 @@ Boot0004* ironic1      HD(1,GPT,55db8d03-c8f6-4a5b-9155-790dddc348fa,0x800,0x640
                     mock.call('udevadm', 'settle'),
                     mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
-                    mock.call('efibootmgr', '-b', '0000', '-B'),
-                    mock.call('efibootmgr', '-b', '0004', '-B'),
+                    mock.call('efibootmgr', '-v', binary=True),
+                    mock.call('efibootmgr', '-b', '0000', '-B', binary=True),
+                    mock.call('efibootmgr', '-b', '0004', '-B', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -450,8 +455,8 @@ Boot0004* ironic1      HD(1,GPT,55db8d03-c8f6-4a5b-9155-790dddc348fa,0x800,0x640
 
         mock_execute.side_effect = iter([('', ''), ('', ''),
                                          ('', ''), ('', ''),
-                                         ('', ''), ('', ''),
-                                         ('', ''), ('', ''),
+                                         (EFI_RESULT, ''), (EFI_RESULT, ''),
+                                         (EFI_RESULT, ''), ('', ''),
                                          ('', '')])
 
         expected = [mock.call('efibootmgr', '--version'),
@@ -460,15 +465,15 @@ Boot0004* ironic1      HD(1,GPT,55db8d03-c8f6-4a5b-9155-790dddc348fa,0x800,0x640
                     mock.call('udevadm', 'settle'),
                     mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'ironic2', '-l',
-                              '\\WINDOWS\\system32\\winload.efi'),
+                              '\\WINDOWS\\system32\\winload.efi', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
diff --git a/ironic_python_agent/tests/unit/test_efi_utils.py b/ironic_python_agent/tests/unit/test_efi_utils.py
index 64de61bc..09e89796 100644
--- a/ironic_python_agent/tests/unit/test_efi_utils.py
+++ b/ironic_python_agent/tests/unit/test_efi_utils.py
@@ -28,6 +28,9 @@ from ironic_python_agent.tests.unit.samples import hardware_samples
 from ironic_python_agent import utils
 
 
+EFI_RESULT = ''.encode('utf-16')
+
+
 @mock.patch.object(os, 'walk', autospec=True)
 @mock.patch.object(os, 'access', autospec=False)
 class TestGetEfiBootloaders(base.IronicAgentTest):
@@ -115,16 +118,16 @@ class TestRunEfiBootmgr(base.IronicAgentTest):
         mock_execute.assert_has_calls(expected)
 
     def test__run_efibootmgr(self, mock_execute):
-        mock_execute.return_value = ('', '')
+        mock_execute.return_value = (''.encode('utf-16'), '')
         result = efi_utils._run_efibootmgr(['EFI/BOOT/BOOTX64.EFI'],
                                            self.fake_dev,
                                            self.fake_efi_system_part,
                                            self.fake_dir)
-        expected = [mock.call('efibootmgr', '-v'),
+        expected = [mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', self.fake_efi_system_part, '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI')]
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True)]
         self.assertIsNone(result)
         mock_execute.assert_has_calls(expected)
 
@@ -176,19 +179,18 @@ class TestManageUefi(base.IronicAgentTest):
         mock_is_md_device.return_value = False
 
         mock_efi_bl.return_value = ['EFI/BOOT/BOOTX64.EFI']
-
-        mock_execute.side_effect = iter([('', ''), ('', ''),
-                                         ('', ''), ('', ''),
+        mock_execute.side_effect = iter([('', ''), (EFI_RESULT, ''),
+                                         (EFI_RESULT, ''), ('', ''),
                                          ('', ''), ('', ''),
                                          ('', '')])
 
         expected = [mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -219,30 +221,34 @@ class TestManageUefi(base.IronicAgentTest):
         # at the start of the file, where as Red Hat *does*
         csv_file_data = u'shimx64.efi,Vendor String,,Grub2MadeUSDoThis\n'
         # This test also handles deleting a pre-existing matching vendor
-        # string in advance.
+        # string in advance. This string also includes a UTF16 character
+        # *on* purpose, to force proper decoding to be tested and garbage
+        # characters which can be found in OVMF test VM NVRAM records.
         dupe_entry = """
 BootCurrent: 0001
 Timeout: 0 seconds
 BootOrder: 0000,00001
-Boot0000* Vendor String HD(1,GPT,4f3c6294-bf9b-4208-9808-be45dfc34b5c)File(\EFI\Boot\BOOTX64.EFI)
-Boot0001 Vendor String HD(2,GPT,4f3c6294-bf9b-4208-9808-be45dfc34b5c)File(\EFI\Boot\BOOTX64.EFI)
-Boot0002: VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
+Boot0000 UTF16ÿ HD(1,GPT,4f3c6294-bf9b-4208-9808-be45dfc34b5c)File(\EFI\Boot\BOOTX64.EFI)
+Boot0001* Vendor String HD(1,GPT,4f3c6294-bf9b-4208-9808-be45dfc34b5c)File(\EFI\Boot\BOOTX64.EFI)
+Boot0002 Vendor String HD(2,GPT,4f3c6294-bf9b-4208-9808-be45dfc34b5c)File(\EFI\Boot\BOOTX64.EFI)
+Boot0003: VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)N.....YM....R,Y.
 """  # noqa This is a giant literal string for testing.
-
-        mock_execute.side_effect = iter([('', ''), (dupe_entry, ''),
+        dupe_entry = dupe_entry.encode('utf-16')
+        mock_execute.side_effect = iter([('', ''),
+                                         (dupe_entry, ''),
                                          ('', ''), ('', ''),
                                          ('', ''), ('', ''),
                                          ('', '')])
 
         expected = [mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
-                    mock.call('efibootmgr', '-b', '0000', '-B'),
-                    mock.call('efibootmgr', '-b', '0001', '-B'),
+                    mock.call('efibootmgr', '-v', binary=True),
+                    mock.call('efibootmgr', '-b', '0001', '-B', binary=True),
+                    mock.call('efibootmgr', '-b', '0002', '-B', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'Vendor String', '-l',
-                              '\\EFI\\vendor\\shimx64.efi'),
+                              '\\EFI\\vendor\\shimx64.efi', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -266,19 +272,18 @@ Boot0002: VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
         mock_is_md_device.return_value = False
 
         mock_efi_bl.return_value = ['EFI/BOOT/BOOTX64.EFI']
-
-        mock_execute.side_effect = iter([('', ''), ('', ''),
-                                         ('', ''), ('', ''),
+        mock_execute.side_effect = iter([('', ''), (EFI_RESULT, ''),
+                                         (EFI_RESULT, ''), ('', ''),
                                          ('', ''), ('', ''),
                                          ('', '')])
 
         expected = [mock.call('mount', '/dev/fakenvme0p1',
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', '/dev/fakenvme0',
                               '-p', '1', '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -301,19 +306,18 @@ Boot0002: VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
         mock_is_md_device.return_value = False
 
         mock_efi_bl.return_value = ['EFI/BOOT/BOOTX64.EFI']
-
-        mock_execute.side_effect = iter([('', ''), ('', ''),
-                                         ('', ''), ('', ''),
+        mock_execute.side_effect = iter([('', ''), (EFI_RESULT, ''),
+                                         (EFI_RESULT, ''), ('', ''),
                                          ('', ''), ('', ''),
                                          ('', '')])
 
         expected = [mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', self.fake_dev,
                               '-p', '1', '-w',
                               '-L', 'ironic1', '-l',
-                              '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -347,11 +351,14 @@ Boot0002: VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
         mock_get_component_devices.return_value = ['/dev/sda3', '/dev/sdb3']
 
         mock_efi_bl.return_value = ['EFI/BOOT/BOOTX64.EFI']
-
-        mock_execute.side_effect = iter([('', ''), ('', ''),
-                                         ('', ''), ('', ''),
-                                         ('', ''), ('', ''),
-                                         ('', ''), ('', ''),
+        mock_execute.side_effect = iter([('', ''),
+                                         ('', ''),
+                                         ('', ''),
+                                         (EFI_RESULT, ''),
+                                         (EFI_RESULT, ''),
+                                         (EFI_RESULT, ''),
+                                         (EFI_RESULT, ''),
+                                         ('', ''),
                                          ('', '')])
 
         expected = [mock.call('mount', self.fake_efi_system_part,
@@ -360,14 +367,14 @@ Boot0002: VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
                               attempts=3, delay_on_retry=True),
                     mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', '/dev/sda3',
                               '-p', '3', '-w', '-L', 'ironic1 (RAID, part0)',
-                              '-l', '\\EFI\\BOOT\\BOOTX64.EFI'),
-                    mock.call('efibootmgr', '-v'),
+                              '-l', '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('efibootmgr', '-v', '-c', '-d', '/dev/sdb3',
                               '-p', '3', '-w', '-L', 'ironic1 (RAID, part1)',
-                              '-l', '\\EFI\\BOOT\\BOOTX64.EFI'),
+                              '-l', '\\EFI\\BOOT\\BOOTX64.EFI', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -425,7 +432,7 @@ Boot0002: VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
 
         expected = [mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True),
                     mock.call('sync')]
@@ -462,7 +469,7 @@ Boot0002: VENDMAGIC FvFile(9f3c6294-bf9b-4208-9808-be45dfc34b51)
 
         expected = [mock.call('mount', self.fake_efi_system_part,
                               self.fake_dir + '/boot/efi'),
-                    mock.call('efibootmgr', '-v'),
+                    mock.call('efibootmgr', '-v', binary=True),
                     mock.call('umount', self.fake_dir + '/boot/efi',
                               attempts=3, delay_on_retry=True)]
 
diff --git a/releasenotes/notes/fixes-efibootmgr-character-encoding-19e531ba694824c1.yaml b/releasenotes/notes/fixes-efibootmgr-character-encoding-19e531ba694824c1.yaml
new file mode 100644
index 00000000..b4c3270c
--- /dev/null
+++ b/releasenotes/notes/fixes-efibootmgr-character-encoding-19e531ba694824c1.yaml
@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Fixes UEFI NVRAM record handling with efibootmgr so we can accept and
+    handle UTF-16 encoded data which is to be expected in UEFI NVRAM as
+    the records are UTF-16 encoded.
+  - |
+    Fixes handling of UEFI NVRAM records to allow for unexpected characters
+    in the response, so it is non-fatal to Ironic.