tpm: add TPM2_PCR_Extend command support

Add support for the TPM2_PCR_Extend command.

Change the command file and the help accordingly.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

diff --git a/cmd/tpm-v2.c b/cmd/tpm-v2.c
index 6f34987037a93dd3e82c4743d4ec85308e906330..0a7a5c807412789d876126d1a78f9e61e6beeb7c 100644 (file)
--- a/cmd/tpm-v2.c
+++ b/cmd/tpm-v2.c
@@ -7,6 +7,7 @@
 #include <common.h>
 #include <dm.h>
 #include <log.h>
+#include <mapmem.h>
 #include <tpm-common.h>
 #include <tpm-v2.h>
 #include "tpm-user-utils.h"
@@ -74,12 +75,44 @@ static int do_tpm2_clear(cmd_tbl_t *cmdtp, int flag, int argc,
        return report_return_code(tpm2_clear(handle, pw, pw_sz));
 }
 
+static int do_tpm2_pcr_extend(cmd_tbl_t *cmdtp, int flag, int argc,
+                             char * const argv[])
+{
+       struct udevice *dev;
+       struct tpm_chip_priv *priv;
+       u32 index = simple_strtoul(argv[1], NULL, 0);
+       void *digest = map_sysmem(simple_strtoul(argv[2], NULL, 0), 0);
+       int ret;
+       u32 rc;
+
+       if (argc != 3)
+               return CMD_RET_USAGE;
+
+       ret = uclass_first_device_err(UCLASS_TPM, &dev);
+       if (ret)
+               return ret;
+
+       priv = dev_get_uclass_priv(dev);
+       if (!priv)
+               return -EINVAL;
+
+       if (index >= priv->pcr_count)
+               return -EINVAL;
+
+       rc = tpm2_pcr_extend(index, digest);
+
+       unmap_sysmem(digest);
+
+       return report_return_code(rc);
+}
+
 static cmd_tbl_t tpm2_commands[] = {
        U_BOOT_CMD_MKENT(info, 0, 1, do_tpm_info, "", ""),
        U_BOOT_CMD_MKENT(init, 0, 1, do_tpm_init, "", ""),
        U_BOOT_CMD_MKENT(startup, 0, 1, do_tpm2_startup, "", ""),
        U_BOOT_CMD_MKENT(self_test, 0, 1, do_tpm2_self_test, "", ""),
        U_BOOT_CMD_MKENT(clear, 0, 1, do_tpm2_clear, "", ""),
+       U_BOOT_CMD_MKENT(pcr_extend, 0, 1, do_tpm2_pcr_extend, "", ""),
 };
 
 cmd_tbl_t *get_tpm_commands(unsigned int *size)
@@ -111,4 +144,8 @@ U_BOOT_CMD(tpm, CONFIG_SYS_MAXARGS, 1, do_tpm, "Issue a TPMv2.x command",
 "    <hierarchy> is one of:\n"
 "        * TPM2_RH_LOCKOUT\n"
 "        * TPM2_RH_PLATFORM\n"
+"pcr_extend <pcr> <digest_addr>\n"
+"    Extend PCR #<pcr> with digest at <digest_addr>.\n"
+"    <pcr>: index of the PCR\n"
+"    <digest_addr>: address of a 32-byte SHA256 digest\n"
 );

diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index cf5dae0a82b074b61fc7fc64088a30e129390ec0..25bb15af393f7dd20c8543186a3c90bb55194909 100644 (file)
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -154,4 +154,14 @@ u32 tpm2_self_test(enum tpm2_yes_no full_test);
  */
 u32 tpm2_clear(u32 handle, const char *pw, const ssize_t pw_sz);
 
+/**
+ * Issue a TPM2_PCR_Extend command.
+ *
+ * @index      Index of the PCR
+ * @digest     Value representing the event to be recorded
+ *
+ * @return code of the operation
+ */
+u32 tpm2_pcr_extend(u32 index, const uint8_t *digest);
+
 #endif /* __TPM_V2_H */

diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 34a93ab06717abcfdcfdc03083a9ff9df260336d..476b4ee0d083bd4f136e6a9c840a7ab0826ba343 100644 (file)
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -77,3 +77,41 @@ u32 tpm2_clear(u32 handle, const char *pw, const ssize_t pw_sz)
 
        return tpm_sendrecv_command(command_v2, NULL, NULL);
 }
+
+u32 tpm2_pcr_extend(u32 index, const uint8_t *digest)
+{
+       u8 command_v2[COMMAND_BUFFER_SIZE] = {
+               tpm_u16(TPM2_ST_SESSIONS),      /* TAG */
+               tpm_u32(33 + TPM2_DIGEST_LEN),  /* Length */
+               tpm_u32(TPM2_CC_PCR_EXTEND),    /* Command code */
+
+               /* HANDLE */
+               tpm_u32(index),                 /* Handle (PCR Index) */
+
+               /* AUTH_SESSION */
+               tpm_u32(9),                     /* Authorization size */
+               tpm_u32(TPM2_RS_PW),            /* Session handle */
+               tpm_u16(0),                     /* Size of <nonce> */
+                                               /* <nonce> (if any) */
+               0,                              /* Attributes: Cont/Excl/Rst */
+               tpm_u16(0),                     /* Size of <hmac/password> */
+                                               /* <hmac/password> (if any) */
+               tpm_u32(1),                     /* Count (number of hashes) */
+               tpm_u16(TPM2_ALG_SHA256),       /* Algorithm of the hash */
+               /* STRING(digest)                  Digest */
+       };
+       unsigned int offset = 33;
+       int ret;
+
+       /*
+        * Fill the command structure starting from the first buffer:
+        *     - the digest
+        */
+       ret = pack_byte_string(command_v2, sizeof(command_v2), "s",
+                              offset, digest, TPM2_DIGEST_LEN);
+       offset += TPM2_DIGEST_LEN;
+       if (ret)
+               return TPM_LIB_ERROR;
+
+       return tpm_sendrecv_command(command_v2, NULL, NULL);
+}