usb_updater: when communicating over tpm treat upgrades differently

All extension and vendor commands' payloads need to be passed to the
processing functions the same way, whether they arrive over /dev/tpm0
or over USB. The upgrade PDUs sent over USB need to include two
additional fields which are stripped off by the reassembly layer on
the Cr50.

This patch makes sure that none of other than EXTENSION_FW_UPGRADE
commands sent over /dev/tpm0 by usb_updater have the extra
encapsulation.

BRANCH=cr50
BUG=b:62106898
TEST=verified that updates work the same way over TPM and USB (which
     includes sending the 'turn_update_on' commands. Before this patch
     the turn_update_on command sent by usb_updater over TPM was not
     processed properly (the timeout value was wrong).

Change-Id: I3f4ab7330037f6eb1ce8bac7c63faa5d7c309c94
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/517416
Reviewed-by: Andrey Pronin <apronin@chromium.org>
(cherry picked from commit bd0f74a6f49cd3dcbed81738e376a8b05868b4f5)
Reviewed-on: https://chromium-review.googlesource.com/658348
Reviewed-by: Philip Chen <philipchen@chromium.org>
Commit-Queue: Philip Chen <philipchen@chromium.org>
Tested-by: Philip Chen <philipchen@chromium.org>

1 files changed, 34 insertions, 13 deletions

diff --git a/extra/usb_updater/usb_updater.c b/extra/usb_updater/usb_updater.c
index 951b26507b..c39673535a 100644
--- a/extra/usb_updater/usb_updater.c
+++ b/extra/usb_updater/usb_updater.c
@@ -176,9 +176,20 @@ struct upgrade_pkt {
 	__be32	length;
 	__be32	ordinal;
 	__be16	subcmd;
-	__be32	digest;
-	__be32	address;
-	char data[0];
+	union {
+		/*
+		 * Upgrade PDUs as opposed to all other vendor and extension
+		 * commands include two additional fields in the header.
+		 */
+		struct {
+			__be32	digest;
+			__be32	address;
+			char data[0];
+		} upgrade;
+		struct {
+			char data[0];
+		} command;
+	};
 } __packed;
 
 #define MAX_BUF_SIZE	(SIGNED_TRANSFER_SIZE + sizeof(struct upgrade_pkt))
@@ -241,26 +252,37 @@ static int tpm_send_pkt(int fd, unsigned int digest, unsigned int addr,
 {
 	/* Used by transfer to /dev/tpm0 */
 	static uint8_t outbuf[MAX_BUF_SIZE];
-
 	struct upgrade_pkt *out = (struct upgrade_pkt *)outbuf;
 	/* Use the same structure, it will not be filled completely. */
 	int len, done;
-	int response_offset = offsetof(struct upgrade_pkt, digest);
+	int response_offset = offsetof(struct upgrade_pkt, command.data);
+	void *payload;
+	size_t header_size;
 
 	debug("%s: sending to %#x %d bytes\n", __func__, addr, size);
 
-	len = size + sizeof(struct upgrade_pkt);
-
 	out->tag = htobe16(0x8001);
-	out->length = htobe32(len);
+	out->subcmd = htobe16(subcmd);
+
 	if (subcmd <= LAST_EXTENSION_COMMAND)
 		out->ordinal = htobe32(CONFIG_EXTENSION_COMMAND);
 	else
 		out->ordinal = htobe32(TPM_CC_VENDOR_BIT_MASK);
-	out->subcmd = htobe16(subcmd);
-	out->digest = digest;
-	out->address = htobe32(addr);
-	memcpy(out->data, data, size);
+
+	if (subcmd == EXTENSION_FW_UPGRADE) {
+		/* FW Upgrade PDU header includes a couple of extra fields. */
+		out->upgrade.digest = digest;
+		out->upgrade.address = htobe32(addr);
+		header_size = offsetof(struct upgrade_pkt, upgrade.data);
+	} else {
+		header_size = offsetof(struct upgrade_pkt, command.data);
+	}
+
+	payload = outbuf + header_size;
+	len = size + header_size;
+
+	out->length = htobe32(len);
+	memcpy(payload, data, size);
 #ifdef DEBUG
 	{
 		int i;
@@ -1113,7 +1135,6 @@ static void generate_reset_request(struct transfer_descriptor *td)
 			fprintf(stderr, "Failed to request posted reboot\n");
 			exit(update_error);
 		}
-
 	}
 
 	printf("reboot %s\n", subcommand == EXTENSION_POST_RESET ?