81 lines
2.5 KiB
Diff
81 lines
2.5 KiB
Diff
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From c3efb4ecbe91b63c127b92122dad3fa53d4efc69 Mon Sep 17 00:00:00 2001
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From: Patrick Colp <patrick.colp@oracle.com>
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Date: Mon, 31 Jul 2023 07:01:45 -0700
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Subject: [PATCH 1/4] protectors: Implement NV index
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Currently with the TPM2 protector, only SRK mode is supported and
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NV index support is just a stub. Implement the NV index option.
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Note: This only extends support on the unseal path. grub2_protect
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has not been updated. tpm2-tools can be used to insert a key into
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the NV index.
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An example of inserting a key using tpm2-tools:
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# Get random key.
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tpm2_getrandom 32 > key.dat
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# Create primary object.
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tpm2_createprimary -C o -g sha256 -G rsa -c primary.ctx
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# Create policy object. `pcrs.dat` contains the PCR values to seal against.
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tpm2_startauthsession -S session.dat
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tpm2_policypcr -S session.dat -l sha256:7,11 -f pcrs.dat -L policy.dat
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tpm2_flushcontext session.dat
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# Seal key into TPM.
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cat key.dat | tpm2_create -C primary.ctx -u key.pub -r key.priv -L policy.dat -i-
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tpm2_load -C primary.ctx -u key.pub -r key.priv -n sealing.name -c sealing.ctx
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tpm2_evictcontrol -C o -c sealing.ctx 0x81000000
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Then to unseal the key in grub, add this to grub.cfg:
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tpm2_key_protector_init --mode=nv --nvindex=0x81000000 --pcrs=7,11
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cryptomount -u <UUID> --protector tpm2
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Signed-off-by: Patrick Colp <patrick.colp@oracle.com>
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---
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grub-core/tpm2/module.c | 25 ++++++++++++++++++++-----
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1 file changed, 20 insertions(+), 5 deletions(-)
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diff --git a/grub-core/tpm2/module.c b/grub-core/tpm2/module.c
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index 5274296b7..d3a64187a 100644
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--- a/grub-core/tpm2/module.c
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+++ b/grub-core/tpm2/module.c
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@@ -757,12 +757,27 @@ static grub_err_t
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grub_tpm2_protector_nv_recover (const struct grub_tpm2_protector_context *ctx,
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grub_uint8_t **key, grub_size_t *key_size)
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{
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- (void)ctx;
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- (void)key;
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- (void)key_size;
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+ TPM_HANDLE sealed_handle = ctx->nv;
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+ tpm2key_policy_t policy_seq = NULL;
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+ grub_err_t err;
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+
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+ /* Create a basic policy sequence based on the given PCR selection */
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+ err = grub_tpm2_protector_simple_policy_seq (ctx, &policy_seq);
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+ if (err != GRUB_ERR_NONE)
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+ goto exit;
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+
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+ err = grub_tpm2_protector_unseal (policy_seq, sealed_handle, key, key_size);
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+
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+ /* Pop error messages on success */
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+ if (err == GRUB_ERR_NONE)
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+ while (grub_error_pop ());
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+
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+exit:
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+ TPM2_FlushContext (sealed_handle);
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- return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
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- N_("NV Index mode is not implemented yet"));
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+ grub_tpm2key_free_policy_seq (policy_seq);
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+
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+ return err;
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}
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static grub_err_t
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--
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2.35.3
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