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25 #include <sys/cdefs.h>
26 __FBSDID("$FreeBSD$");
28 #include "libsecureboot-priv.h"
31 * To support measured boot without putting a ton
32 * of extra code in the loader, we just maintain
33 * a hash of all the hashes we (attempt to) verify.
34 * The loader can export this for kernel or rc script
35 * to feed to a TPM pcr register - hence the name ve_pcr.
37 * NOTE: in the current standard the TPM pcr register size is for SHA1,
38 * the fact that we provide a SHA256 hash should not matter
39 * as long as we are consistent - it can be truncated or hashed
40 * before feeding to TPM.
43 static const br_hash_class *pcr_md = NULL;
44 static br_hash_compat_context pcr_ctx;
45 static size_t pcr_hlen = 0;
46 static int pcr_updating;
49 * @brief initialize pcr context
51 * Real TPM registers only hold a SHA1 hash
58 pcr_hlen = br_sha256_SIZE;
59 pcr_md = &br_sha256_vtable;
60 pcr_md->init(&pcr_ctx.vtable);
64 * @brief get pcr_updating state
67 ve_pcr_updating_get(void)
69 return (pcr_updating);
73 * @brief set pcr_updating state
76 ve_pcr_updating_set(int updating)
78 pcr_updating = updating;
82 * @brief update pcr context
85 ve_pcr_update(unsigned char *data, size_t dlen)
87 if (pcr_updating != 0 && pcr_md != NULL)
88 pcr_md->update(&pcr_ctx.vtable, data, dlen);
92 * @brief get pcr result
95 ve_pcr_get(unsigned char *buf, size_t sz)
101 pcr_md->out(&pcr_ctx.vtable, buf);