Update the user manual to address TPM2 key protector including the two
related commands, tpm2_key_protector_init and tpm2_key_protector_clear,
and the user-space utility: grub-protect.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
For the tpm2_key_protector module, the TCG2 command submission function
is the only difference between a QEMU instance and grub-emu. To test
TPM2 key unsealing with a QEMU instance, it requires an extra OS image
to invoke grub-protect to seal the LUKS key, rather than a simple
grub-shell rescue CD image. On the other hand, grub-emu can share the
emulated TPM2 device with the host, so that we can seal the LUKS key on
host and test key unsealing with grub-emu.
This test script firstly creates a simple LUKS image to be loaded as a
loopback device in grub-emu. Then an emulated TPM2 device is created by
"swtpm chardev" and PCR 0 and 1 are extended.
There are several test cases in the script to test various settings. Each
test case uses grub-protect or tpm2-tools to seal the LUKS password
with PCR 0 and PCR 1. Then grub-emu is launched to load the LUKS image,
try to mount the image with tpm2_key_protector_init and cryptomount, and
verify the result.
Based on the idea from Michael Chang.
Cc: Michael Chang <mchang@suse.com>
Cc: Stefan Berger <stefanb@linux.ibm.com>
Cc: Glenn Washburn <development@efficientek.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
As a preparation to test tpm2_key_protector with grub-emu, the new
option, --tpm-device, is introduced to specify the TPM device for
grub-emu so that grub-emu can access an emulated TPM device from
the host.
Since grub-emu can directly access the device on host, it's easy to
implement the essential TCG2 command submission function with the
read/write functions and enable tpm2_key_protector module for grub-emu,
so that we can further test TPM2 key unsealing with grub-emu.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
When using disk auto-unlocking with TPM 2.0, the typical grub.cfg may
look like this:
tpm2_key_protector_init --tpm2key=(hd0,gpt1)/boot/grub/sealed.tpm
cryptomount -u <PART-UUID> -P tpm2
search --fs-uuid --set=root <FS-UUID>
Since the disk search order is based on the order of module loading, the
attacker could insert a malicious disk with the same FS-UUID root to
trick GRUB to boot into the malicious root and further dump memory to
steal the unsealed key.
Do defend against such an attack, we can specify the hint provided by
"grub-probe" to search the encrypted partition first:
search --fs-uuid --set=root --hint='cryptouuid/<PART-UUID>' <FS-UUID>
However, for LVM on an encrypted partition, the search hint provided by
"grub-probe" is:
--hint='lvmid/<VG-UUID>/<LV-UUID>'
It doesn't guarantee to look up the logical volume from the encrypted
partition, so the attacker may have the chance to fool GRUB to boot
into the malicious disk.
To minimize the attack surface, this commit tweaks the disk device search
in diskfilter to look up cryptodisk devices first and then others, so
that the auto-unlocked disk will be found first, not the attacker's disk.
Cc: Fabian Vogt <fvogt@suse.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
An attacker may insert a malicious disk with the same crypto UUID and
trick GRUB to mount the fake root. Even though the key from the key
protector fails to unlock the fake root, it's not wiped out cleanly so
the attacker could dump the memory to retrieve the secret key. To defend
such attack, wipe out the cached key when we don't need it.
Cc: Fabian Vogt <fvogt@suse.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
This commit handles the TPM2_PolicyAuthorize command from the key file
in TPM 2.0 Key File format.
TPM2_PolicyAuthorize is the essential command to support authorized
policy which allows the users to sign TPM policies with their own keys.
Per TPM 2.0 Key File [1], CommandPolicy for TPM2_PolicyAuthorize
comprises "TPM2B_PUBLIC pubkey", "TPM2B_DIGEST policy_ref", and
"TPMT_SIGNATURE signature". To verify the signature, the current policy
digest is hashed with the hash algorithm written in "signature", and then
"signature" is verified with the hashed policy digest and "pubkey". Once
TPM accepts "signature", TPM2_PolicyAuthorize is invoked to authorize the
signed policy.
To create the key file with authorized policy, here are the pcr-oracle [2]
commands:
# Generate the RSA key and create the authorized policy file
$ pcr-oracle \
--rsa-generate-key \
--private-key policy-key.pem \
--auth authorized.policy \
create-authorized-policy 0,2,4,7,9
# Seal the secret with the authorized policy
$ pcr-oracle \
--key-format tpm2.0 \
--auth authorized.policy \
--input disk-secret.txt \
--output sealed.key \
seal-secret
# Sign the predicted PCR policy
$ pcr-oracle \
--key-format tpm2.0 \
--private-key policy-key.pem \
--from eventlog \
--stop-event "grub-file=grub.cfg" \
--after \
--input sealed.key \
--output /boot/efi/efi/grub/sealed.tpm \
sign 0,2,4,7,9
Then specify the key file and the key protector to grub.cfg in the EFI
system partition:
tpm2_key_protector_init -a RSA --tpm2key=(hd0,gpt1)/efi/grub/sealed.tpm
cryptomount -u <PART_UUID> -P tpm2
For any change in the boot components, just run the "sign" command again
to update the signature in sealed.tpm, and TPM can unseal the key file
with the updated PCR policy.
[1] https://www.hansenpartnership.com/draft-bottomley-tpm2-keys.html
[2] https://github.com/okirch/pcr-oracle
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
A Trusted Platform Module (TPM) Software Stack (TSS) provides logic to
compose and submit TPM commands and parse responses.
A limited number of TPM commands may be accessed via the EFI TCG2
protocol. This protocol exposes functionality that is primarily geared
toward TPM usage within the context of Secure Boot. For all other TPM
commands, however, such as sealing and unsealing, this protocol does not
provide any help, with the exception of passthrough command submission.
The SubmitCommand method allows a caller to send raw commands to the
system's TPM and to receive the corresponding response. These
command/response pairs are formatted using the TPM wire protocol. To
construct commands in this way, and to parse the TPM's response, it is
necessary to, first, possess knowledge of the various TPM structures, and,
second, of the TPM wire protocol itself.
As such, this patch includes implementations of various grub_tpm2_* functions
(inventoried below), and logic to write and read command and response
buffers, respectively, using the TPM wire protocol.
Functions:
- grub_tpm2_create(),
- grub_tpm2_createprimary(),
- grub_tpm2_evictcontrol(),
- grub_tpm2_flushcontext(),
- grub_tpm2_load(),
- grub_tpm2_pcr_read(),
- grub_tpm2_policygetdigest(),
- grub_tpm2_policypcr(),
- grub_tpm2_readpublic(),
- grub_tpm2_startauthsession(),
- grub_tpm2_unseal(),
- grub_tpm2_loadexternal(),
- grub_tpm2_hash(),
- grub_tpm2_verifysignature(),
- grub_tpm2_policyauthorize(),
- grub_tpm2_testparms().
Signed-off-by: Hernan Gatta <hegatta@linux.microsoft.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
This commit adds the necessary TPM2 types and structs as the preparation
for the TPM2 Software Stack (TSS2) support. The Marshal/Unmarshal
functions are also added to handle the data structure to be submitted to
TPM2 commands and to be received from the response.
Signed-off-by: Hernan Gatta <hegatta@linux.microsoft.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
As the preparation to support TPM2 Software Stack (TSS2), this commit
implements the TPM2 buffer handling functions to pack data for the TPM2
commands and unpack the data from the response.
Cc: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Hernan Gatta <hegatta@linux.microsoft.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Document libtasn1 in docs/grub-dev.texi and add the upgrade steps.
Also add the patches to make libtasn1 compatible with GRUB code.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
There is a testcase to test the values larger than "int" but smaller
than "long". However, for some architectures, "long" and "int" are the
same and the compiler may issue a warning like this:
grub-core/tests/asn1/tests/Test_overflow.c:48:50: error: left shift of negative value [-Werror=shift-negative-value]
unsigned long num = ((long) GRUB_UINT_MAX) << 2;
^~
To avoid unnecessary error the testcase is enabled only when
GRUB_LONG_MAX is larger than GRUB_INT_MAX.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
This commit replaces printf() and fprintf() with grub_printf() to print
the error messages for the testcases. Besides, asn1_strerror() is used
to convert the result code to strings instead of asn1_perror().
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Some testcases use exit() to end the test. Since all the asn1 testcases
are invoked as functions, this commit replaces exit() with return to
reflect the test results, so that the main test function can check the
results.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
This commit changes the main functions in the testcases to the test
names so that the real "main" test function can invokes them.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
This commit removes all the headers and only uses asn1_test.h.
To avoid including int.h from grub-core/lib/libtasn1-grub/lib,
CONST_DOWN is defined in reproducers.c.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
In _asn1_tag_der(), the first while loop for the long form may end up
with a "k" value with "ASN1_MAX_TAG_SIZE" and cause the buffer overrun
in the second while loop. This commit tweaks the conditional check to
avoid producing a too large "k".
This is a quick fix and may differ from the official upstream fix.
libtasn1 issue: https://gitlab.com/gnutls/libtasn1/-/issues/49
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Replace a 64-bit division with a call to grub_divmod64(), preventing
creation of __udivdi3() calls on 32-bit platforms.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Since libtasn1.h is the header to be included by users, including the
standard POSIX headers in libtasn1.h would force the user to add the
CFLAGS/CPPFLAGS for the POSIX headers.
This commit adjusts the header paths to use the grub headers instead of
the standard POSIX headers, so that users only need to include
libtasn1.h to use libtasn1 functions.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
strcat() is not available in GRUB. This commit replaces strcat() and
_asn1_strcat() with the bounds-checking _asn1_str_cat().
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
strcat() is not available in GRUB. This commit replaces strcat() with
strcpy() in _asn1_str_cat() as the preparation to replace other strcat()
with the bounds-checking _asn1_str_cat().
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
We don't expect to be able to write ASN.1, only read it,
so we can disable some code.
Do that with #if 0/#endif, rather than deletion. This means
that the difference between upstream and GRUB is smaller,
which should make updating libtasn1 easier in the future.
With these exclusions we also avoid the need for minmax.h,
which is convenient because it means we don't have to
import it from gnulib.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
_split_longopt() was the bash-completion private API and removed since
bash-completion 2.12. This commit initializes the bash-completion
general variables with _init_completion() to avoid the potential
"command not found" error.
Although bash-completion 2.12 introduces _comp_initialize() to deprecate
_init_completion(), _init_completion() is still chosen for the better
backward compatibility.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
There are two system directories for bash-completion scripts. One is
/usr/share/bash-completion/completions/ and the other is
/etc/bash_completion.d/. The "etc" scripts are loaded in advance and
for backward compatibility while the "usr" scripts are loaded on demand.
To load scripts on demand it requires a corresponding script for every
command. So, the main bash-completion script is split into several
subscripts for different "grub-*" commands. To share the code the real
completion functions are still implemented in "grub" and each
subscript sources "grub" and invokes the corresponding function.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When adding/changing the password for the luks2 partition, cryptsetup
may reject the command due to the weak password. Since this is only for
testing, add "--force-password" to switch password quality check off to
avoid the unexpected failure.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Per "man 5 cpio", the namesize in the cpio header includes the trailing
NUL byte of the pathname and the pathname is followed by NUL bytes, but
the current implementation ignores the trailing NUL byte when making
the newc header. Although make_header() tries to pad the pathname string,
the padding won't happen when strlen(name) + sizeof(struct newc_head)
is a multiple of 4, and the non-NULL-terminated pathname may lead to
unexpected results.
Assume that a file is created with 'echo -n aaaa > /boot/test12' and
loaded by grub2:
linux /boot/vmlinuz
initrd newc:test12:/boot/test12 /boot/initrd
The initrd command eventually invoked grub_initrd_load() and sent
't''e''s''t''1''2' to make_header() to generate the header:
00000070 30 37 30 37 30 31 33 30 31 43 41 30 44 45 30 30 |070701301CA0DE00|
00000080 30 30 38 31 41 34 30 30 30 30 30 33 45 38 30 30 |0081A4000003E800|
00000090 30 30 30 30 36 34 30 30 30 30 30 30 30 31 36 33 |0000640000000163|
000000a0 37 36 45 34 35 32 30 30 30 30 30 30 30 34 30 30 |76E4520000000400|
000000b0 30 30 30 30 30 38 30 30 30 30 30 30 31 33 30 30 |0000080000001300|
000000c0 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
000000d0 30 30 30 30 30 36 30 30 30 30 30 30 30 30 74 65 |00000600000000te|
^namesize
000000e0 73 74 31 32 61 61 61 61 30 37 30 37 30 31 30 30 |st12aaaa07070100|
^^ end of the pathname
Since strlen("test12") + sizeof(struct newc_head) is 116 = 29 * 4,
make_header() didn't pad the pathname, and the file content followed
"test12" immediately. This violates the cpio format and may trigger such
error during linux boot:
Initramfs unpacking failed: ZSTD-compressed data is trunc
To avoid the potential problems, this commit counts the trailing NUL byte
in when calling make_header() and adjusts the initrd size accordingly.
Now the header becomes
00000070 30 37 30 37 30 31 33 30 31 43 41 30 44 45 30 30 |070701301CA0DE00|
00000080 30 30 38 31 41 34 30 30 30 30 30 33 45 38 30 30 |0081A4000003E800|
00000090 30 30 30 30 36 34 30 30 30 30 30 30 30 31 36 33 |0000640000000163|
000000a0 37 36 45 34 35 32 30 30 30 30 30 30 30 34 30 30 |76E4520000000400|
000000b0 30 30 30 30 30 38 30 30 30 30 30 30 31 33 30 30 |0000080000001300|
000000c0 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
000000d0 30 30 30 30 30 37 30 30 30 30 30 30 30 30 74 65 |00000700000000te|
^namesize
000000e0 73 74 31 32 00 00 00 00 61 61 61 61 30 37 30 37 |st12....aaaa0707|
^^ end of the pathname
Besides the trailing NUL byte, make_header() pads 3 more NUL bytes, and
the user can safely read the pathname without a further check.
To conform to the cpio format, the headers for "TRAILER!!!" are also
adjusted to include the trailing NUL byte, not ignore it.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Gary Lin