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25 #include <sys/cdefs.h>
26 __FBSDID("$FreeBSD$");
28 #include <sys/queue.h>
29 #include "libsecureboot-priv.h"
32 * To support measured boot without putting a ton
33 * of extra code in the loader, we just maintain
34 * a hash of all the hashes we (attempt to) verify.
35 * The loader can export this for kernel or rc script
36 * to feed to a TPM pcr register - hence the name ve_pcr.
38 * NOTE: in the current standard the TPM pcr register size is for SHA1,
39 * the fact that we provide a SHA256 hash should not matter
40 * as long as we are consistent - it can be truncated or hashed
41 * before feeding to TPM.
44 static const br_hash_class *pcr_md = NULL;
45 static br_hash_compat_context pcr_ctx;
46 static size_t pcr_hlen = 0;
47 static int pcr_updating = -1;
51 const char *hi_basename;
52 STAILQ_ENTRY(hashed_info) entries;
55 static STAILQ_HEAD(, hashed_info) hi_list;
59 * @brief initialize pcr context
61 * Real TPM registers only hold a SHA1 hash
67 if (pcr_updating < 0) {
69 pcr_hlen = br_sha256_SIZE;
70 pcr_md = &br_sha256_vtable;
71 pcr_md->init(&pcr_ctx.vtable);
72 STAILQ_INIT(&hi_list);
77 * @brief get pcr_updating state
80 ve_pcr_updating_get(void)
82 return (pcr_updating);
86 * @brief set pcr_updating state
89 ve_pcr_updating_set(int updating)
91 pcr_updating = updating;
95 * @brief update pcr context
98 ve_pcr_update(const char *path, unsigned char *data, size_t dlen)
100 struct hashed_info *hip;
102 if (pcr_updating > 0 && pcr_md != NULL) {
103 pcr_md->update(&pcr_ctx.vtable, data, dlen);
104 /* if mallocs fail, measured boot will likely fail too */
105 if ((hip = malloc(sizeof(struct hashed_info)))) {
106 hip->hi_path = strdup(path);
111 hip->hi_basename = strrchr(hip->hi_path, '/');
112 if (hip->hi_basename) {
115 hip->hi_basename = hip->hi_path;
117 STAILQ_INSERT_TAIL(&hi_list, hip, entries);
123 * @brief get pcr result
126 ve_pcr_get(unsigned char *buf, size_t sz)
132 pcr_md->out(&pcr_ctx.vtable, buf);
137 * @brief get list of paths in prc
140 ve_pcr_hashed_get(int flags)
144 struct hashed_info *hip;
152 STAILQ_FOREACH(hip, &hi_list, entries) {
153 nbytes += 1 + strlen(flags ? hip->hi_basename : hip->hi_path);
156 hinfo = malloc(nbytes + 2);
158 STAILQ_FOREACH(hip, &hi_list, entries) {
159 cp = flags ? hip->hi_basename : hip->hi_path;
160 n = snprintf(&hinfo[x], nbytes - x, "%s,", cp);