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[PATCH v18 20/25] tpm2_key_protector: Implement NV index
From: |
Gary Lin |
Subject: |
[PATCH v18 20/25] tpm2_key_protector: Implement NV index |
Date: |
Fri, 28 Jun 2024 16:19:03 +0800 |
From: Patrick Colp <patrick.colp@oracle.com>
Currently with the TPM2 protector, only SRK mode is supported and
NV index support is just a stub. Implement the NV index option.
Note: This only extends support on the unseal path. grub2_protect
has not been updated. tpm2-tools can be used to insert a key into
the NV index.
An example of inserting a key using tpm2-tools:
# Get random key.
tpm2_getrandom 32 > key.dat
# Create primary object.
tpm2_createprimary -C o -g sha256 -G ecc -c primary.ctx
# Create policy object. `pcrs.dat` contains the PCR values to seal against.
tpm2_startauthsession -S session.dat
tpm2_policypcr -S session.dat -l sha256:7,11 -f pcrs.dat -L policy.dat
tpm2_flushcontext session.dat
# Seal key into TPM.
cat key.dat | tpm2_create -C primary.ctx -u key.pub -r key.priv -L policy.dat
-i-
tpm2_load -C primary.ctx -u key.pub -r key.priv -n sealing.name -c sealing.ctx
tpm2_evictcontrol -C o -c sealing.ctx 0x81000000
Then to unseal the key in grub, add this to grub.cfg:
tpm2_key_protector_init --mode=nv --nvindex=0x81000000 --pcrs=7,11
cryptomount -u <UUID> --protector tpm2
Signed-off-by: Patrick Colp <patrick.colp@oracle.com>
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
---
.../commands/tpm2_key_protector/module.c | 27 ++++++++++++++++---
1 file changed, 23 insertions(+), 4 deletions(-)
diff --git a/grub-core/commands/tpm2_key_protector/module.c
b/grub-core/commands/tpm2_key_protector/module.c
index a98109c43..ae412e6f4 100644
--- a/grub-core/commands/tpm2_key_protector/module.c
+++ b/grub-core/commands/tpm2_key_protector/module.c
@@ -981,11 +981,30 @@ grub_tpm2_protector_srk_recover (const struct
grub_tpm2_protector_context *ctx,
}
static grub_err_t
-grub_tpm2_protector_nv_recover (const struct grub_tpm2_protector_context *ctx
__attribute__ ((unused)),
- grub_uint8_t **key __attribute__ ((unused)),
- grub_size_t *key_size __attribute__ ((unused)))
+grub_tpm2_protector_nv_recover (const struct grub_tpm2_protector_context *ctx,
+ grub_uint8_t **key, grub_size_t *key_size)
{
- return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, N_("NV Index mode is not
implemented yet"));
+ TPM_HANDLE sealed_handle = ctx->nv;
+ tpm2key_policy_t policy_seq = NULL;
+ grub_err_t err;
+
+ /* Create a basic policy sequence based on the given PCR selection */
+ err = grub_tpm2_protector_simple_policy_seq (ctx, &policy_seq);
+ if (err != GRUB_ERR_NONE)
+ goto exit;
+
+ err = grub_tpm2_protector_unseal (policy_seq, sealed_handle, key, key_size);
+
+ /* Pop error messages on success */
+ if (err == GRUB_ERR_NONE)
+ while (grub_error_pop ());
+
+ exit:
+ TPM2_FlushContext (sealed_handle);
+
+ grub_tpm2key_free_policy_seq (policy_seq);
+
+ return err;
}
static grub_err_t
--
2.35.3
- Re: [PATCH v18 12/25] key_protector: Add key protectors framework, (continued)
- [PATCH v18 13/25] tss2: Add TPM2 buffer handling functions, Gary Lin, 2024/06/28
- [PATCH v18 14/25] tss2: Add TPM2 types and Marshal/Unmarshal functions, Gary Lin, 2024/06/28
- [PATCH v18 15/25] tss2: Add TPM2 Software Stack (TSS2) support, Gary Lin, 2024/06/28
- [PATCH v18 16/25] key_protector: Add TPM2 Key Protector, Gary Lin, 2024/06/28
- [PATCH v18 17/25] cryptodisk: Support key protectors, Gary Lin, 2024/06/28
- [PATCH v18 18/25] util/grub-protect: Add new tool, Gary Lin, 2024/06/28
- [PATCH v18 19/25] tpm2_key_protector: Support authorized policy, Gary Lin, 2024/06/28
- [PATCH v18 21/25] cryptodisk: Fallback to passphrase, Gary Lin, 2024/06/28
- [PATCH v18 20/25] tpm2_key_protector: Implement NV index,
Gary Lin <=
- [PATCH v18 22/25] cryptodisk: wipe out the cached keys from protectors, Gary Lin, 2024/06/28
- [PATCH v18 25/25] tests: Add tpm2_key_protector_test, Gary Lin, 2024/06/28
- [PATCH v18 23/25] diskfilter: look up cryptodisk devices first, Gary Lin, 2024/06/28
- [PATCH v18 24/25] tpm2_key_protector: Add grub-emu support, Gary Lin, 2024/06/28