mount-encrypted: expprt nvram contents to tmpfs
Export the NVRAM contents to tmpfs (/tmp) for use during boot without
incurring the cost of repeated trips through the TPM.
Signed-off-by: Will Drewry <wad@chromium.org>
BUG=chromium-os:37367
TEST=builds, boots, emits lockbox.nvram which validates using in-progress lockbox-cache
BRANCH=none
Change-Id: I8b1103f4bd22bd75e98a7617a571bdb3a06d2914
Previous-Reviewed-on: https://gerrit.chromium.org/gerrit/41433
Commit-Queue: Will Drewry <wad@chromium.org>
(cherry picked from commit 265e2f78dd46845253b683ca8367483c31ba3f4a)
Reviewed-on: https://gerrit.chromium.org/gerrit/42114
Commit-Queue: Mattias Nissler <mnissler@chromium.org>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
Tested-by: Mattias Nissler <mnissler@chromium.org>
diff --git a/utility/mount-encrypted.c b/utility/mount-encrypted.c
index a97db0c..98e63e7 100644
--- a/utility/mount-encrypted.c
+++ b/utility/mount-encrypted.c
@@ -41,6 +41,7 @@
#define ENCRYPTED_MNT STATEFUL_MNT "/encrypted"
#define BUF_SIZE 1024
#define PROP_SIZE 64
+#define LOCKBOX_SIZE_MAX 0x45
static const gchar * const kKernelCmdline = "/proc/cmdline";
static const gchar * const kKernelCmdlineOption = " encrypted-stateful-key=";
@@ -48,11 +49,12 @@
static const gchar * const kCryptDevName = "encstateful";
static const gchar * const kTpmDev = "/dev/tpm0";
static const gchar * const kNullDev = "/dev/null";
+static const gchar * const kNvramExport = "/tmp/lockbox.nvram";
static const float kSizePercent = 0.3;
static const float kMigrationSizeMultiplier = 1.1;
static const uint32_t kLockboxIndex = 0x20000004;
static const uint32_t kLockboxSizeV1 = 0x2c;
-static const uint32_t kLockboxSizeV2 = 0x45;
+static const uint32_t kLockboxSizeV2 = LOCKBOX_SIZE_MAX;
static const uint32_t kLockboxSaltOffset = 0x5;
static const uint64_t kSectorSize = 512;
static const uint64_t kExt4BlockSize = 4096;
@@ -111,6 +113,8 @@
static gchar *dmcrypt_dev = NULL;
static int has_tpm = 0;
static int tpm_init_called = 0;
+static uint8_t nvram_data[LOCKBOX_SIZE_MAX];
+static uint32_t nvram_size = 0;
static void tpm_init(void)
{
@@ -352,6 +356,12 @@
return 0;
}
+ /* "Export" nvram data for use after the helper. */
+ if (size <= sizeof(nvram_data)) {
+ nvram_size = size;
+ memcpy(nvram_data, value, size);
+ }
+
/* Choose random bytes to use based on NVRAM version. */
if (*migrate) {
rand_bytes = value;
@@ -1271,6 +1281,25 @@
exit(1);
}
+/* Exports NVRAM contents to tmpfs for use by install attributes */
+void nvram_export(uint8_t *data, uint32_t size)
+{
+ int fd;
+ DEBUG("Export NVRAM contents");
+ if (!size || !data)
+ return;
+ fd = open(kNvramExport, O_WRONLY|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
+ if (fd < 0) {
+ perror("open(nvram_export)");
+ return;
+ }
+ if (write(fd, data, size) != size) {
+ /* Don't leave broken files around */
+ unlink(kNvramExport);
+ }
+ close(fd);
+}
+
int main(int argc, char *argv[])
{
int okay;
@@ -1301,6 +1330,9 @@
okay = setup_encrypted(mode);
/* If we fail, let chromeos_startup handle the stateful wipe. */
+ if (okay)
+ nvram_export(nvram_data, nvram_size);
+
INFO_DONE("Done.");
/* Continue boot. */
