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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
commit55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch)
tree33f869f55a1b149e9b7c2b7e201867ca5dd52992 /src/libsystemd/sd-journal/journal-authenticate.c
parentInitial commit. (diff)
downloadsystemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.tar.xz
systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.zip
Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/libsystemd/sd-journal/journal-authenticate.c')
-rw-r--r--src/libsystemd/sd-journal/journal-authenticate.c525
1 files changed, 525 insertions, 0 deletions
diff --git a/src/libsystemd/sd-journal/journal-authenticate.c b/src/libsystemd/sd-journal/journal-authenticate.c
new file mode 100644
index 0000000..8e7533e
--- /dev/null
+++ b/src/libsystemd/sd-journal/journal-authenticate.c
@@ -0,0 +1,525 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#include "fd-util.h"
+#include "fsprg.h"
+#include "gcrypt-util.h"
+#include "hexdecoct.h"
+#include "journal-authenticate.h"
+#include "journal-def.h"
+#include "journal-file.h"
+#include "memory-util.h"
+#include "time-util.h"
+
+static void* fssheader_free(FSSHeader *p) {
+ /* mmap() returns MAP_FAILED on error and sets the errno */
+ if (!p || p == MAP_FAILED)
+ return NULL;
+
+ assert_se(munmap(p, PAGE_ALIGN(sizeof(FSSHeader))) >= 0);
+ return NULL;
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(FSSHeader*, fssheader_free);
+
+static uint64_t journal_file_tag_seqnum(JournalFile *f) {
+ uint64_t r;
+
+ assert(f);
+
+ r = le64toh(f->header->n_tags) + 1;
+ f->header->n_tags = htole64(r);
+
+ return r;
+}
+
+int journal_file_append_tag(JournalFile *f) {
+ Object *o;
+ uint64_t p;
+ int r;
+
+ assert(f);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ if (!f->hmac_running) {
+ r = journal_file_hmac_start(f);
+ if (r < 0)
+ return r;
+ }
+
+ assert(f->hmac);
+
+ r = journal_file_append_object(f, OBJECT_TAG, sizeof(struct TagObject), &o, &p);
+ if (r < 0)
+ return r;
+
+ o->tag.seqnum = htole64(journal_file_tag_seqnum(f));
+ o->tag.epoch = htole64(FSPRG_GetEpoch(f->fsprg_state));
+
+ log_debug("Writing tag %"PRIu64" for epoch %"PRIu64"",
+ le64toh(o->tag.seqnum),
+ FSPRG_GetEpoch(f->fsprg_state));
+
+ /* Add the tag object itself, so that we can protect its
+ * header. This will exclude the actual hash value in it */
+ r = journal_file_hmac_put_object(f, OBJECT_TAG, o, p);
+ if (r < 0)
+ return r;
+
+ /* Get the HMAC tag and store it in the object */
+ memcpy(o->tag.tag, gcry_md_read(f->hmac, 0), TAG_LENGTH);
+ f->hmac_running = false;
+
+ return 0;
+}
+
+int journal_file_hmac_start(JournalFile *f) {
+ uint8_t key[256 / 8]; /* Let's pass 256 bit from FSPRG to HMAC */
+ gcry_error_t err;
+
+ assert(f);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ if (f->hmac_running)
+ return 0;
+
+ /* Prepare HMAC for next cycle */
+ gcry_md_reset(f->hmac);
+ FSPRG_GetKey(f->fsprg_state, key, sizeof(key), 0);
+ err = gcry_md_setkey(f->hmac, key, sizeof(key));
+ if (gcry_err_code(err) != GPG_ERR_NO_ERROR)
+ return log_debug_errno(SYNTHETIC_ERRNO(EIO),
+ "gcry_md_setkey() failed with error code: %s",
+ gcry_strerror(err));
+
+ f->hmac_running = true;
+
+ return 0;
+}
+
+static int journal_file_get_epoch(JournalFile *f, uint64_t realtime, uint64_t *epoch) {
+ uint64_t t;
+
+ assert(f);
+ assert(epoch);
+ assert(JOURNAL_HEADER_SEALED(f->header));
+
+ if (f->fss_start_usec == 0 || f->fss_interval_usec == 0)
+ return -EOPNOTSUPP;
+
+ if (realtime < f->fss_start_usec)
+ return -ESTALE;
+
+ t = realtime - f->fss_start_usec;
+ t = t / f->fss_interval_usec;
+
+ *epoch = t;
+
+ return 0;
+}
+
+static int journal_file_fsprg_need_evolve(JournalFile *f, uint64_t realtime) {
+ uint64_t goal, epoch;
+ int r;
+
+ assert(f);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ r = journal_file_get_epoch(f, realtime, &goal);
+ if (r < 0)
+ return r;
+
+ epoch = FSPRG_GetEpoch(f->fsprg_state);
+ if (epoch > goal)
+ return -ESTALE;
+
+ return epoch != goal;
+}
+
+int journal_file_fsprg_evolve(JournalFile *f, uint64_t realtime) {
+ uint64_t goal, epoch;
+ int r;
+
+ assert(f);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ r = journal_file_get_epoch(f, realtime, &goal);
+ if (r < 0)
+ return r;
+
+ epoch = FSPRG_GetEpoch(f->fsprg_state);
+ if (epoch < goal)
+ log_debug("Evolving FSPRG key from epoch %"PRIu64" to %"PRIu64".", epoch, goal);
+
+ for (;;) {
+ if (epoch > goal)
+ return -ESTALE;
+ if (epoch == goal)
+ return 0;
+
+ FSPRG_Evolve(f->fsprg_state);
+ epoch = FSPRG_GetEpoch(f->fsprg_state);
+ if (epoch < goal) {
+ r = journal_file_append_tag(f);
+ if (r < 0)
+ return r;
+ }
+ }
+}
+
+int journal_file_fsprg_seek(JournalFile *f, uint64_t goal) {
+ void *msk;
+ uint64_t epoch;
+
+ assert(f);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ assert(f->fsprg_seed);
+
+ if (f->fsprg_state) {
+ /* Cheaper... */
+
+ epoch = FSPRG_GetEpoch(f->fsprg_state);
+ if (goal == epoch)
+ return 0;
+
+ if (goal == epoch + 1) {
+ FSPRG_Evolve(f->fsprg_state);
+ return 0;
+ }
+ } else {
+ f->fsprg_state_size = FSPRG_stateinbytes(FSPRG_RECOMMENDED_SECPAR);
+ f->fsprg_state = malloc(f->fsprg_state_size);
+ if (!f->fsprg_state)
+ return -ENOMEM;
+ }
+
+ log_debug("Seeking FSPRG key to %"PRIu64".", goal);
+
+ msk = alloca_safe(FSPRG_mskinbytes(FSPRG_RECOMMENDED_SECPAR));
+ FSPRG_GenMK(msk, NULL, f->fsprg_seed, f->fsprg_seed_size, FSPRG_RECOMMENDED_SECPAR);
+ FSPRG_Seek(f->fsprg_state, goal, msk, f->fsprg_seed, f->fsprg_seed_size);
+
+ return 0;
+}
+
+int journal_file_maybe_append_tag(JournalFile *f, uint64_t realtime) {
+ int r;
+
+ assert(f);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ if (realtime <= 0)
+ realtime = now(CLOCK_REALTIME);
+
+ r = journal_file_fsprg_need_evolve(f, realtime);
+ if (r <= 0)
+ return 0;
+
+ r = journal_file_append_tag(f);
+ if (r < 0)
+ return r;
+
+ r = journal_file_fsprg_evolve(f, realtime);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int journal_file_hmac_put_object(JournalFile *f, ObjectType type, Object *o, uint64_t p) {
+ int r;
+
+ assert(f);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ r = journal_file_hmac_start(f);
+ if (r < 0)
+ return r;
+
+ if (!o) {
+ r = journal_file_move_to_object(f, type, p, &o);
+ if (r < 0)
+ return r;
+ } else if (type > OBJECT_UNUSED && o->object.type != type)
+ return -EBADMSG;
+
+ gcry_md_write(f->hmac, o, offsetof(ObjectHeader, payload));
+
+ switch (o->object.type) {
+
+ case OBJECT_DATA:
+ /* All but hash and payload are mutable */
+ gcry_md_write(f->hmac, &o->data.hash, sizeof(o->data.hash));
+ gcry_md_write(f->hmac, journal_file_data_payload_field(f, o), le64toh(o->object.size) - journal_file_data_payload_offset(f));
+ break;
+
+ case OBJECT_FIELD:
+ /* Same here */
+ gcry_md_write(f->hmac, &o->field.hash, sizeof(o->field.hash));
+ gcry_md_write(f->hmac, o->field.payload, le64toh(o->object.size) - offsetof(Object, field.payload));
+ break;
+
+ case OBJECT_ENTRY:
+ /* All */
+ gcry_md_write(f->hmac, &o->entry.seqnum, le64toh(o->object.size) - offsetof(Object, entry.seqnum));
+ break;
+
+ case OBJECT_FIELD_HASH_TABLE:
+ case OBJECT_DATA_HASH_TABLE:
+ case OBJECT_ENTRY_ARRAY:
+ /* Nothing: everything is mutable */
+ break;
+
+ case OBJECT_TAG:
+ /* All but the tag itself */
+ gcry_md_write(f->hmac, &o->tag.seqnum, sizeof(o->tag.seqnum));
+ gcry_md_write(f->hmac, &o->tag.epoch, sizeof(o->tag.epoch));
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int journal_file_hmac_put_header(JournalFile *f) {
+ int r;
+
+ assert(f);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ r = journal_file_hmac_start(f);
+ if (r < 0)
+ return r;
+
+ /* All but state+reserved, boot_id, arena_size,
+ * tail_object_offset, n_objects, n_entries,
+ * tail_entry_seqnum, head_entry_seqnum, entry_array_offset,
+ * head_entry_realtime, tail_entry_realtime,
+ * tail_entry_monotonic, n_data, n_fields, n_tags,
+ * n_entry_arrays. */
+
+ gcry_md_write(f->hmac, f->header->signature, offsetof(Header, state) - offsetof(Header, signature));
+ gcry_md_write(f->hmac, &f->header->file_id, offsetof(Header, tail_entry_boot_id) - offsetof(Header, file_id));
+ gcry_md_write(f->hmac, &f->header->seqnum_id, offsetof(Header, arena_size) - offsetof(Header, seqnum_id));
+ gcry_md_write(f->hmac, &f->header->data_hash_table_offset, offsetof(Header, tail_object_offset) - offsetof(Header, data_hash_table_offset));
+
+ return 0;
+}
+
+int journal_file_fss_load(JournalFile *f) {
+ _cleanup_close_ int fd = -EBADF;
+ _cleanup_free_ char *path = NULL;
+ _cleanup_(fssheader_freep) FSSHeader *header = NULL;
+ struct stat st;
+ sd_id128_t machine;
+ int r;
+
+ assert(f);
+
+ /* This function is used to determine whether sealing should be enabled in the journal header so we
+ * can't check the header to check if sealing is enabled here. */
+
+ r = sd_id128_get_machine(&machine);
+ if (r < 0)
+ return r;
+
+ if (asprintf(&path, "/var/log/journal/" SD_ID128_FORMAT_STR "/fss",
+ SD_ID128_FORMAT_VAL(machine)) < 0)
+ return -ENOMEM;
+
+ fd = open(path, O_RDWR|O_CLOEXEC|O_NOCTTY, 0600);
+ if (fd < 0) {
+ if (errno != ENOENT)
+ log_error_errno(errno, "Failed to open %s: %m", path);
+
+ return -errno;
+ }
+
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ if (st.st_size < (off_t) sizeof(FSSHeader))
+ return -ENODATA;
+
+ header = mmap(NULL, PAGE_ALIGN(sizeof(FSSHeader)), PROT_READ, MAP_SHARED, fd, 0);
+ if (header == MAP_FAILED)
+ return -errno;
+
+ if (memcmp(header->signature, FSS_HEADER_SIGNATURE, 8) != 0)
+ return -EBADMSG;
+
+ if (header->incompatible_flags != 0)
+ return -EPROTONOSUPPORT;
+
+ if (le64toh(header->header_size) < sizeof(FSSHeader))
+ return -EBADMSG;
+
+ if (le64toh(header->fsprg_state_size) != FSPRG_stateinbytes(le16toh(header->fsprg_secpar)))
+ return -EBADMSG;
+
+ f->fss_file_size = le64toh(header->header_size) + le64toh(header->fsprg_state_size);
+ if ((uint64_t) st.st_size < f->fss_file_size)
+ return -ENODATA;
+
+ if (!sd_id128_equal(machine, header->machine_id))
+ return -EHOSTDOWN;
+
+ if (le64toh(header->start_usec) <= 0 || le64toh(header->interval_usec) <= 0)
+ return -EBADMSG;
+
+ size_t sz = PAGE_ALIGN(f->fss_file_size);
+ assert(sz < SIZE_MAX);
+ f->fss_file = mmap(NULL, sz, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+ if (f->fss_file == MAP_FAILED) {
+ f->fss_file = NULL;
+ return -errno;
+ }
+
+ f->fss_start_usec = le64toh(f->fss_file->start_usec);
+ f->fss_interval_usec = le64toh(f->fss_file->interval_usec);
+
+ f->fsprg_state = (uint8_t*) f->fss_file + le64toh(f->fss_file->header_size);
+ f->fsprg_state_size = le64toh(f->fss_file->fsprg_state_size);
+
+ return 0;
+}
+
+int journal_file_hmac_setup(JournalFile *f) {
+ gcry_error_t e;
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ initialize_libgcrypt(true);
+
+ e = gcry_md_open(&f->hmac, GCRY_MD_SHA256, GCRY_MD_FLAG_HMAC);
+ if (e != 0)
+ return -EOPNOTSUPP;
+
+ return 0;
+}
+
+int journal_file_append_first_tag(JournalFile *f) {
+ uint64_t p;
+ int r;
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return 0;
+
+ log_debug("Calculating first tag...");
+
+ r = journal_file_hmac_put_header(f);
+ if (r < 0)
+ return r;
+
+ p = le64toh(f->header->field_hash_table_offset);
+ if (p < offsetof(Object, hash_table.items))
+ return -EINVAL;
+ p -= offsetof(Object, hash_table.items);
+
+ r = journal_file_hmac_put_object(f, OBJECT_FIELD_HASH_TABLE, NULL, p);
+ if (r < 0)
+ return r;
+
+ p = le64toh(f->header->data_hash_table_offset);
+ if (p < offsetof(Object, hash_table.items))
+ return -EINVAL;
+ p -= offsetof(Object, hash_table.items);
+
+ r = journal_file_hmac_put_object(f, OBJECT_DATA_HASH_TABLE, NULL, p);
+ if (r < 0)
+ return r;
+
+ r = journal_file_append_tag(f);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int journal_file_parse_verification_key(JournalFile *f, const char *key) {
+ _cleanup_free_ uint8_t *seed = NULL;
+ size_t seed_size;
+ const char *k;
+ unsigned long long start, interval;
+ int r;
+
+ assert(f);
+ assert(key);
+
+ seed_size = FSPRG_RECOMMENDED_SEEDLEN;
+ seed = malloc(seed_size);
+ if (!seed)
+ return -ENOMEM;
+
+ k = key;
+ for (size_t c = 0; c < seed_size; c++) {
+ int x, y;
+
+ k = skip_leading_chars(k, "-");
+
+ x = unhexchar(*k);
+ if (x < 0)
+ return -EINVAL;
+ k++;
+
+ y = unhexchar(*k);
+ if (y < 0)
+ return -EINVAL;
+ k++;
+
+ seed[c] = (uint8_t) (x * 16 + y);
+ }
+
+ if (*k != '/')
+ return -EINVAL;
+ k++;
+
+ r = sscanf(k, "%llx-%llx", &start, &interval);
+ if (r != 2)
+ return -EINVAL;
+
+ f->fsprg_seed = TAKE_PTR(seed);
+ f->fsprg_seed_size = seed_size;
+
+ f->fss_start_usec = start * interval;
+ f->fss_interval_usec = interval;
+
+ return 0;
+}
+
+bool journal_file_next_evolve_usec(JournalFile *f, usec_t *u) {
+ uint64_t epoch;
+
+ assert(f);
+ assert(u);
+
+ if (!JOURNAL_HEADER_SEALED(f->header))
+ return false;
+
+ epoch = FSPRG_GetEpoch(f->fsprg_state);
+
+ *u = (usec_t) (f->fss_start_usec + f->fss_interval_usec * epoch + f->fss_interval_usec);
+
+ return true;
+}