[PATCH] Add support for TSS2 for PCR reading

[PATCH] Add support for TSS2 for PCR reading

[Patrick Uiterwijk]

Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>
---
 configure.ac |   5 +++
 src/evmctl.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 118 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index eedf90e..58a7fee 100644
--- a/configure.ac
+++ b/configure.ac
@@ -35,6 +35,9 @@ if test "x$TSSPCRREAD" = "xyes"; then
 	AC_DEFINE(HAVE_TSSPCRREAD, 1, [Define to 1 if you have tsspcrread
binary installed])],
 fi

+AC_CHECK_LIB([tss2-esys], [Esys_PCR_Read])
+AC_CHECK_LIB([tss2-rc], [Tss2_RC_Decode])
+
 AC_CHECK_HEADERS(sys/xattr.h, , [AC_MSG_ERROR([sys/xattr.h header not
found. You need the c-library development package.])])
 AC_CHECK_HEADERS(keyutils.h, , [AC_MSG_ERROR([keyutils.h header not
found. You need the libkeyutils development package.])])

@@ -78,4 +81,6 @@ echo	"Configuration:"
 echo	"          debug: $pkg_cv_enable_debug"
 echo	"   openssl-conf: $enable_openssl_conf"
 echo	"     tsspcrread: $TSSPCRREAD"
+echo	"      tss2-esys: $ac_cv_lib_tss2_esys_Esys_PCR_Read"
+echo	" tss2-rc-decode: $ac_cv_lib_tss2_rc_Tss2_RC_Decode"
 echo
diff --git a/src/evmctl.c b/src/evmctl.c
index b02be8b..5bc6773 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -69,6 +69,15 @@
 #define XATTR_NAME_APPARMOR XATTR_SECURITY_PREFIX XATTR_APPARMOR_SUFFIX
 #endif

+#ifdef HAVE_LIBTSS2_ESYS
+#include <tss2/tss2_esys.h>
+
+#ifdef HAVE_LIBTSS2_RC
+#include <tss2/tss2_rc.h>
+#endif
+#endif
+
+
 #define USE_FPRINTF

 #include "imaevm.h"
@@ -1407,9 +1416,110 @@ static int tpm_pcr_read(int idx, uint8_t *pcr, int len)
 	return result;
 }

-#ifdef HAVE_TSSPCRREAD
+#ifdef HAVE_LIBTSS2_ESYS
+static int pcr_selections_match(TPML_PCR_SELECTION *a, TPML_PCR_SELECTION *b)
+{
+	if (a->count != b->count)
+		return 0;
+	for (int i = 0; i < a->count; i++) {
+		if (a->pcrSelections[i].hash != b->pcrSelections[i].hash)
+			return 0;
+		if (a->pcrSelections[i].sizeofSelect != b->pcrSelections[i].sizeofSelect)
+			return 0;
+		for (int j = 0; j < a->pcrSelections[i].sizeofSelect; j++) {
+			if (a->pcrSelections[i].pcrSelect[j] != b->pcrSelections[i].pcrSelect[j])
+				return 0;
+		}
+	}
+
+	return 1;
+}
+
+static inline int tpm2_set_errmsg(char **errmsg, const char *message,
TSS2_RC ret)
+{
+#ifdef HAVE_LIBTSS2_RC
+		ret = asprintf(errmsg, "%s: %s", message, Tss2_RC_Decode(ret));
+#else
+		ret = asprintf(errmsg, "%s: #%d", message, ret);
+#endif
+}
+#endif
+
 static int tpm2_pcr_read(int idx, uint8_t *hwpcr, int len, char **errmsg)
 {
+#if defined(HAVE_LIBTSS2_ESYS)
+	TSS2_ABI_VERSION abi_version = {
+		.tssCreator = 1,
+		.tssFamily = 2,
+		.tssLevel = 1,
+		.tssVersion = 108,
+	};
+	ESYS_CONTEXT *ctx = NULL;
+	TSS2_RC ret = 0;
+	TPML_PCR_SELECTION pcr_select_in = {
+		.count = 1,
+		.pcrSelections = {
+			{
+				.hash = TPM2_ALG_SHA1,
+				.sizeofSelect = 3,
+				.pcrSelect = { 0x00, 0x00, 0x00 },
+			}
+		}
+	};
+	TPML_PCR_SELECTION *pcr_select_out;
+	TPML_DIGEST *pcr_digests;
+	UINT32 pcr_update_counter;
+
+	pcr_select_in.pcrSelections[0].pcrSelect[idx / 8] = (1 << (idx % 8));
+
+	ret = Esys_Initialize(&ctx, NULL, &abi_version);
+	if (ret != 0) {
+		ret = tpm2_set_errmsg(errmsg, "esys initialize failed", ret);
+		if (ret == -1)	/* the contents of errmsg are undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+
+	ret = Esys_PCR_Read(ctx,
+			    ESYS_TR_NONE,
+			    ESYS_TR_NONE,
+			    ESYS_TR_NONE,
+			    &pcr_select_in,
+			    &pcr_update_counter,
+			    &pcr_select_out,
+			    &pcr_digests);
+	Esys_Finalize(&ctx);
+	if (ret != 0) {
+		ret = tpm2_set_errmsg(errmsg, "esys PCR reading failed", ret);
+		if (ret == -1)	/* the contents of errmsg is undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+
+	if (!pcr_selections_match(&pcr_select_in, pcr_select_out)) {
+		Esys_Free(pcr_select_out);
+		Esys_Free(pcr_digests);
+
+		ret = asprintf(errmsg, "TPM returned incorrect PCRs");
+		if (ret == -1)	/* the contents of errmsg are undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+	Esys_Free(pcr_select_out);
+
+	if (pcr_digests->count != 1 || pcr_digests->digests[0].size !=
SHA_DIGEST_LENGTH) {
+		Esys_Free(pcr_digests);
+		ret = asprintf(errmsg, "TPM returned incorrect digests");
+		if (ret == -1)	/* the contents of errmsg is undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+
+	memcpy(hwpcr, pcr_digests->digests[0].buffer, len);
+	Esys_Free(pcr_digests);
+	return 0;
+
+#elif defined(HAVE_TSSPCRREAD)
 	FILE *fp;
 	char pcr[100];	/* may contain an error */
 	char cmd[50];
@@ -1441,8 +1551,8 @@ static int tpm2_pcr_read(int idx, uint8_t
*hwpcr, int len, char **errmsg)
 		*errmsg = strndup(pcr, strlen(pcr) - 1); /* remove newline */

 	return ret;
-}
 #endif
+}

 #define TCG_EVENT_NAME_LEN_MAX	255

@@ -1701,7 +1811,7 @@ static int ima_measurement(const char *file)
 		log_dump(pcr[i], SHA_DIGEST_LENGTH);

 		if (tpm_pcr_read(i, hwpcr, sizeof(hwpcr))) {
-#ifdef HAVE_TSSPCRREAD
+#if defined(HAVE_TSSPCRREAD) || defined(HAVE_LIBTSS2_ESYS)
 			char *errmsg = NULL;

 			err = tpm2_pcr_read(i, hwpcr, sizeof(hwpcr), &errmsg);
-- 
2.24.1

Re: [PATCH] Add support for TSS2 for PCR reading

[Mimi Zohar]

Hi Patrick,

On Sat, 2020-01-25 at 02:15 -0800, Patrick Uiterwijk wrote:
> Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>

Sorry for the long delay in reviewing the posted ima-evm-utils
patches, including yours.  I'm hoping to get back to working on ima-
evm-utils soon.

Mimi
 
> ---
>  configure.ac |   5 +++
>  src/evmctl.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++--
>  2 files changed, 118 insertions(+), 3 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index eedf90e..58a7fee 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -35,6 +35,9 @@ if test "x$TSSPCRREAD" = "xyes"; then
>  	AC_DEFINE(HAVE_TSSPCRREAD, 1, [Define to 1 if you have tsspcrread
> binary installed])],
>  fi
> 
> +AC_CHECK_LIB([tss2-esys], [Esys_PCR_Read])
> +AC_CHECK_LIB([tss2-rc], [Tss2_RC_Decode])
> +
>  AC_CHECK_HEADERS(sys/xattr.h, , [AC_MSG_ERROR([sys/xattr.h header not
> found. You need the c-library development package.])])
>  AC_CHECK_HEADERS(keyutils.h, , [AC_MSG_ERROR([keyutils.h header not
> found. You need the libkeyutils development package.])])
> 
> @@ -78,4 +81,6 @@ echo	"Configuration:"
>  echo	"          debug: $pkg_cv_enable_debug"
>  echo	"   openssl-conf: $enable_openssl_conf"
>  echo	"     tsspcrread: $TSSPCRREAD"
> +echo	"      tss2-esys: $ac_cv_lib_tss2_esys_Esys_PCR_Read"
> +echo	" tss2-rc-decode: $ac_cv_lib_tss2_rc_Tss2_RC_Decode"
>  echo
> diff --git a/src/evmctl.c b/src/evmctl.c
> index b02be8b..5bc6773 100644
> --- a/src/evmctl.c
> +++ b/src/evmctl.c
> @@ -69,6 +69,15 @@
>  #define XATTR_NAME_APPARMOR XATTR_SECURITY_PREFIX XATTR_APPARMOR_SUFFIX
>  #endif
> 
> +#ifdef HAVE_LIBTSS2_ESYS
> +#include <tss2/tss2_esys.h>
> +
> +#ifdef HAVE_LIBTSS2_RC
> +#include <tss2/tss2_rc.h>
> +#endif
> +#endif
> +
> +
>  #define USE_FPRINTF
> 
>  #include "imaevm.h"
> @@ -1407,9 +1416,110 @@ static int tpm_pcr_read(int idx, uint8_t *pcr, int len)
>  	return result;
>  }
> 
> -#ifdef HAVE_TSSPCRREAD
> +#ifdef HAVE_LIBTSS2_ESYS
> +static int pcr_selections_match(TPML_PCR_SELECTION *a, TPML_PCR_SELECTION *b)
> +{
> +	if (a->count != b->count)
> +		return 0;
> +	for (int i = 0; i < a->count; i++) {
> +		if (a->pcrSelections[i].hash != b->pcrSelections[i].hash)
> +			return 0;
> +		if (a->pcrSelections[i].sizeofSelect != b->pcrSelections[i].sizeofSelect)
> +			return 0;
> +		for (int j = 0; j < a->pcrSelections[i].sizeofSelect; j++) {
> +			if (a->pcrSelections[i].pcrSelect[j] != b->pcrSelections[i].pcrSelect[j])
> +				return 0;
> +		}
> +	}
> +
> +	return 1;
> +}
> +
> +static inline int tpm2_set_errmsg(char **errmsg, const char *message,
> TSS2_RC ret)
> +{
> +#ifdef HAVE_LIBTSS2_RC
> +		ret = asprintf(errmsg, "%s: %s", message, Tss2_RC_Decode(ret));
> +#else
> +		ret = asprintf(errmsg, "%s: #%d", message, ret);
> +#endif
> +}
> +#endif
> +
>  static int tpm2_pcr_read(int idx, uint8_t *hwpcr, int len, char **errmsg)
>  {
> +#if defined(HAVE_LIBTSS2_ESYS)
> +	TSS2_ABI_VERSION abi_version = {
> +		.tssCreator = 1,
> +		.tssFamily = 2,
> +		.tssLevel = 1,
> +		.tssVersion = 108,
> +	};
> +	ESYS_CONTEXT *ctx = NULL;
> +	TSS2_RC ret = 0;
> +	TPML_PCR_SELECTION pcr_select_in = {
> +		.count = 1,
> +		.pcrSelections = {
> +			{
> +				.hash = TPM2_ALG_SHA1,
> +				.sizeofSelect = 3,
> +				.pcrSelect = { 0x00, 0x00, 0x00 },
> +			}
> +		}
> +	};
> +	TPML_PCR_SELECTION *pcr_select_out;
> +	TPML_DIGEST *pcr_digests;
> +	UINT32 pcr_update_counter;
> +
> +	pcr_select_in.pcrSelections[0].pcrSelect[idx / 8] = (1 << (idx % 8));
> +
> +	ret = Esys_Initialize(&ctx, NULL, &abi_version);
> +	if (ret != 0) {
> +		ret = tpm2_set_errmsg(errmsg, "esys initialize failed", ret);
> +		if (ret == -1)	/* the contents of errmsg are undefined */
> +			*errmsg = NULL;
> +		return -1;
> +	}
> +
> +	ret = Esys_PCR_Read(ctx,
> +			    ESYS_TR_NONE,
> +			    ESYS_TR_NONE,
> +			    ESYS_TR_NONE,
> +			    &pcr_select_in,
> +			    &pcr_update_counter,
> +			    &pcr_select_out,
> +			    &pcr_digests);
> +	Esys_Finalize(&ctx);
> +	if (ret != 0) {
> +		ret = tpm2_set_errmsg(errmsg, "esys PCR reading failed", ret);
> +		if (ret == -1)	/* the contents of errmsg is undefined */
> +			*errmsg = NULL;
> +		return -1;
> +	}
> +
> +	if (!pcr_selections_match(&pcr_select_in, pcr_select_out)) {
> +		Esys_Free(pcr_select_out);
> +		Esys_Free(pcr_digests);
> +
> +		ret = asprintf(errmsg, "TPM returned incorrect PCRs");
> +		if (ret == -1)	/* the contents of errmsg are undefined */
> +			*errmsg = NULL;
> +		return -1;
> +	}
> +	Esys_Free(pcr_select_out);
> +
> +	if (pcr_digests->count != 1 || pcr_digests->digests[0].size !=
> SHA_DIGEST_LENGTH) {
> +		Esys_Free(pcr_digests);
> +		ret = asprintf(errmsg, "TPM returned incorrect digests");
> +		if (ret == -1)	/* the contents of errmsg is undefined */
> +			*errmsg = NULL;
> +		return -1;
> +	}
> +
> +	memcpy(hwpcr, pcr_digests->digests[0].buffer, len);
> +	Esys_Free(pcr_digests);
> +	return 0;
> +
> +#elif defined(HAVE_TSSPCRREAD)
>  	FILE *fp;
>  	char pcr[100];	/* may contain an error */
>  	char cmd[50];
> @@ -1441,8 +1551,8 @@ static int tpm2_pcr_read(int idx, uint8_t
> *hwpcr, int len, char **errmsg)
>  		*errmsg = strndup(pcr, strlen(pcr) - 1); /* remove newline */
> 
>  	return ret;
> -}
>  #endif
> +}
> 
>  #define TCG_EVENT_NAME_LEN_MAX	255
> 
> @@ -1701,7 +1811,7 @@ static int ima_measurement(const char *file)
>  		log_dump(pcr[i], SHA_DIGEST_LENGTH);
> 
>  		if (tpm_pcr_read(i, hwpcr, sizeof(hwpcr))) {
> -#ifdef HAVE_TSSPCRREAD
> +#if defined(HAVE_TSSPCRREAD) || defined(HAVE_LIBTSS2_ESYS)
>  			char *errmsg = NULL;
> 
>  			err = tpm2_pcr_read(i, hwpcr, sizeof(hwpcr), &errmsg);

Re: [PATCH] Add support for TSS2 for PCR reading

[Mimi Zohar]

Hi Patrick,

On Sat, 2020-01-25 at 02:15 -0800, Patrick Uiterwijk wrote:
> Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>

The new ifdef in tpm2_pcr_read() is rather long, cluttering evmctl.c.
 Moving tpm2_pcr_read() to it's own file, perhaps naming it tpmtss.c,
will help.

thanks,
  
Mimi

> ---
>  configure.ac |   5 +++
>  src/evmctl.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++--
>  2 files changed, 118 insertions(+), 3 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index eedf90e..58a7fee 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -35,6 +35,9 @@ if test "x$TSSPCRREAD" = "xyes"; then
>  	AC_DEFINE(HAVE_TSSPCRREAD, 1, [Define to 1 if you have tsspcrread
> binary installed])],
>  fi
> 
> +AC_CHECK_LIB([tss2-esys], [Esys_PCR_Read])
> +AC_CHECK_LIB([tss2-rc], [Tss2_RC_Decode])
> +
>  AC_CHECK_HEADERS(sys/xattr.h, , [AC_MSG_ERROR([sys/xattr.h header not
> found. You need the c-library development package.])])
>  AC_CHECK_HEADERS(keyutils.h, , [AC_MSG_ERROR([keyutils.h header not
> found. You need the libkeyutils development package.])])
> 
> @@ -78,4 +81,6 @@ echo	"Configuration:"
>  echo	"          debug: $pkg_cv_enable_debug"
>  echo	"   openssl-conf: $enable_openssl_conf"
>  echo	"     tsspcrread: $TSSPCRREAD"
> +echo	"      tss2-esys: $ac_cv_lib_tss2_esys_Esys_PCR_Read"
> +echo	" tss2-rc-decode: $ac_cv_lib_tss2_rc_Tss2_RC_Decode"
>  echo
> diff --git a/src/evmctl.c b/src/evmctl.c
> index b02be8b..5bc6773 100644
> --- a/src/evmctl.c
> +++ b/src/evmctl.c
> @@ -69,6 +69,15 @@
>  #define XATTR_NAME_APPARMOR XATTR_SECURITY_PREFIX XATTR_APPARMOR_SUFFIX
>  #endif
> 
> +#ifdef HAVE_LIBTSS2_ESYS
> +#include <tss2/tss2_esys.h>
> +
> +#ifdef HAVE_LIBTSS2_RC
> +#include <tss2/tss2_rc.h>
> +#endif
> +#endif
> +
> +
>  #define USE_FPRINTF
> 
>  #include "imaevm.h"
> @@ -1407,9 +1416,110 @@ static int tpm_pcr_read(int idx, uint8_t *pcr, int len)
>  	return result;
>  }
> 
> -#ifdef HAVE_TSSPCRREAD
> +#ifdef HAVE_LIBTSS2_ESYS
> +static int pcr_selections_match(TPML_PCR_SELECTION *a, TPML_PCR_SELECTION *b)
> +{
> +	if (a->count != b->count)
> +		return 0;
> +	for (int i = 0; i < a->count; i++) {
> +		if (a->pcrSelections[i].hash != b->pcrSelections[i].hash)
> +			return 0;
> +		if (a->pcrSelections[i].sizeofSelect != b->pcrSelections[i].sizeofSelect)
> +			return 0;
> +		for (int j = 0; j < a->pcrSelections[i].sizeofSelect; j++) {
> +			if (a->pcrSelections[i].pcrSelect[j] != b->pcrSelections[i].pcrSelect[j])
> +				return 0;
> +		}
> +	}
> +
> +	return 1;
> +}
> +
> +static inline int tpm2_set_errmsg(char **errmsg, const char *message,
> TSS2_RC ret)
> +{
> +#ifdef HAVE_LIBTSS2_RC
> +		ret = asprintf(errmsg, "%s: %s", message, Tss2_RC_Decode(ret));
> +#else
> +		ret = asprintf(errmsg, "%s: #%d", message, ret);
> +#endif
> +}
> +#endif
> +
>  static int tpm2_pcr_read(int idx, uint8_t *hwpcr, int len, char **errmsg)
>  {
> +#if defined(HAVE_LIBTSS2_ESYS)
> +	TSS2_ABI_VERSION abi_version = {
> +		.tssCreator = 1,
> +		.tssFamily = 2,
> +		.tssLevel = 1,
> +		.tssVersion = 108,
> +	};
> +	ESYS_CONTEXT *ctx = NULL;
> +	TSS2_RC ret = 0;
> +	TPML_PCR_SELECTION pcr_select_in = {
> +		.count = 1,
> +		.pcrSelections = {
> +			{
> +				.hash = TPM2_ALG_SHA1,
> +				.sizeofSelect = 3,
> +				.pcrSelect = { 0x00, 0x00, 0x00 },
> +			}
> +		}
> +	};
> +	TPML_PCR_SELECTION *pcr_select_out;
> +	TPML_DIGEST *pcr_digests;
> +	UINT32 pcr_update_counter;
> +
> +	pcr_select_in.pcrSelections[0].pcrSelect[idx / 8] = (1 << (idx % 8));
> +
> +	ret = Esys_Initialize(&ctx, NULL, &abi_version);
> +	if (ret != 0) {
> +		ret = tpm2_set_errmsg(errmsg, "esys initialize failed", ret);
> +		if (ret == -1)	/* the contents of errmsg are undefined */
> +			*errmsg = NULL;
> +		return -1;
> +	}
> +
> +	ret = Esys_PCR_Read(ctx,
> +			    ESYS_TR_NONE,
> +			    ESYS_TR_NONE,
> +			    ESYS_TR_NONE,
> +			    &pcr_select_in,
> +			    &pcr_update_counter,
> +			    &pcr_select_out,
> +			    &pcr_digests);
> +	Esys_Finalize(&ctx);
> +	if (ret != 0) {
> +		ret = tpm2_set_errmsg(errmsg, "esys PCR reading failed", ret);
> +		if (ret == -1)	/* the contents of errmsg is undefined */
> +			*errmsg = NULL;
> +		return -1;
> +	}
> +
> +	if (!pcr_selections_match(&pcr_select_in, pcr_select_out)) {
> +		Esys_Free(pcr_select_out);
> +		Esys_Free(pcr_digests);
> +
> +		ret = asprintf(errmsg, "TPM returned incorrect PCRs");
> +		if (ret == -1)	/* the contents of errmsg are undefined */
> +			*errmsg = NULL;
> +		return -1;
> +	}
> +	Esys_Free(pcr_select_out);
> +
> +	if (pcr_digests->count != 1 || pcr_digests->digests[0].size !=
> SHA_DIGEST_LENGTH) {
> +		Esys_Free(pcr_digests);
> +		ret = asprintf(errmsg, "TPM returned incorrect digests");
> +		if (ret == -1)	/* the contents of errmsg is undefined */
> +			*errmsg = NULL;
> +		return -1;
> +	}
> +
> +	memcpy(hwpcr, pcr_digests->digests[0].buffer, len);
> +	Esys_Free(pcr_digests);
> +	return 0;
> +
> +#elif defined(HAVE_TSSPCRREAD)
>  	FILE *fp;
>  	char pcr[100];	/* may contain an error */
>  	char cmd[50];
> @@ -1441,8 +1551,8 @@ static int tpm2_pcr_read(int idx, uint8_t
> *hwpcr, int len, char **errmsg)
>  		*errmsg = strndup(pcr, strlen(pcr) - 1); /* remove newline */
> 
>  	return ret;
> -}
>  #endif
> +}
> 
>  #define TCG_EVENT_NAME_LEN_MAX	255
> 
> @@ -1701,7 +1811,7 @@ static int ima_measurement(const char *file)
>  		log_dump(pcr[i], SHA_DIGEST_LENGTH);
> 
>  		if (tpm_pcr_read(i, hwpcr, sizeof(hwpcr))) {
> -#ifdef HAVE_TSSPCRREAD
> +#if defined(HAVE_TSSPCRREAD) || defined(HAVE_LIBTSS2_ESYS)
>  			char *errmsg = NULL;
> 
>  			err = tpm2_pcr_read(i, hwpcr, sizeof(hwpcr), &errmsg);

Re: [PATCH] Add support for TSS2 for PCR reading

[Mimi Zohar]

Hi Patrick,

On Sun, 2020-02-16 at 21:10 -0500, Mimi Zohar wrote:
> On Sat, 2020-01-25 at 02:15 -0800, Patrick Uiterwijk wrote:
> > Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>
> 
> The new ifdef in tpm2_pcr_read() is rather long, cluttering evmctl.c.
>  Moving tpm2_pcr_read() to it's own file, perhaps naming it tpmtss.c,
> will help.

Could you make this change based on top of the patch set "[RFC PATCH
0/8] ima-evm-utils: calculate per TPM bank template digest" I posted
late last week?

thanks,

Mimi

[PATCH v2] ima-evm-utils: Add support for Intel TSS2 for PCR reading

[patrick]

From: Patrick Uiterwijk <patrick@puiterwijk.org>

This patch makes it possible to use the Intel TSS2 for getting
PCR values from the SHA1/SHA256 banks on a TPM2.
It is somewhat naive as it doesn't use the multi-PCR selection
that TSS2 is capable of, that is for a future patch.

Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>
---
 configure.ac         |   7 ++
 src/Makefile.am      |  12 ++-
 src/evmctl.c         |  85 +--------------------
 src/pcr.h            |   3 +
 src/pcr_none.c       |  52 +++++++++++++
 src/pcr_tss.c        | 178 +++++++++++++++++++++++++++++++++++++++++++
 src/pcr_tsspcrread.c |  94 +++++++++++++++++++++++
 src/utils.c          |  32 ++++++++
 src/utils.h          |   5 ++
 9 files changed, 385 insertions(+), 83 deletions(-)
 create mode 100644 src/pcr.h
 create mode 100644 src/pcr_none.c
 create mode 100644 src/pcr_tss.c
 create mode 100644 src/pcr_tsspcrread.c
 create mode 100644 src/utils.c
 create mode 100644 src/utils.h

diff --git a/configure.ac b/configure.ac
index eedf90e..09b24fc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -34,6 +34,11 @@ AC_CHECK_PROG(TSSPCRREAD, [tsspcrread], yes, no)
 if test "x$TSSPCRREAD" = "xyes"; then
 	AC_DEFINE(HAVE_TSSPCRREAD, 1, [Define to 1 if you have tsspcrread
binary installed])],
 fi
+AM_CONDITIONAL([USE_PCRTSSPCRREAD], [test "x$TSSPCRREAD" = "xyes"])
+
+AC_CHECK_LIB([tss2-esys], [Esys_PCR_Read])
+AC_CHECK_LIB([tss2-rc], [Tss2_RC_Decode])
+AM_CONDITIONAL([USE_PCRTSS], [test
"x$ac_cv_lib_tss2_esys_Esys_PCR_Read" = "xyes"])

 AC_CHECK_HEADERS(sys/xattr.h, , [AC_MSG_ERROR([sys/xattr.h header not
found. You need the c-library development package.])])
 AC_CHECK_HEADERS(keyutils.h, , [AC_MSG_ERROR([keyutils.h header not
found. You need the libkeyutils development package.])])
@@ -78,4 +83,6 @@ echo	"Configuration:"
 echo	"          debug: $pkg_cv_enable_debug"
 echo	"   openssl-conf: $enable_openssl_conf"
 echo	"     tsspcrread: $TSSPCRREAD"
+echo	"      tss2-esys: $ac_cv_lib_tss2_esys_Esys_PCR_Read"
+echo	" tss2-rc-decode: $ac_cv_lib_tss2_rc_Tss2_RC_Decode"
 echo
diff --git a/src/Makefile.am b/src/Makefile.am
index b794c50..3665242 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -17,11 +17,21 @@ hash_info.h: Makefile

 bin_PROGRAMS = evmctl

-evmctl_SOURCES = evmctl.c
+evmctl_SOURCES = evmctl.c utils.c
 evmctl_CPPFLAGS = $(AM_CPPFLAGS) $(LIBCRYPTO_CFLAGS)
 evmctl_LDFLAGS = $(LDFLAGS_READLINE)
 evmctl_LDADD =  $(LIBCRYPTO_LIBS) -lkeyutils libimaevm.la

+if USE_PCRTSS
+evmctl_SOURCES += pcr_tss.c
+else
+if USE_PCRTSSPCRREAD
+evmctl_SOURCES += pcr_tsspcrread.c
+else
+evmctl_SOURCES += pcr_none.c
+endif
+endif
+
 AM_CPPFLAGS = -I$(top_srcdir) -include config.h

 CLEANFILES = hash_info.h
diff --git a/src/evmctl.c b/src/evmctl.c
index 27df8ee..97f9c6e 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -64,6 +64,8 @@
 #include <openssl/rsa.h>
 #include <openssl/engine.h>
 #include "hash_info.h"
+#include "pcr.h"
+#include "utils.h"

 #ifndef XATTR_APPAARMOR_SUFFIX
 #define XATTR_APPARMOR_SUFFIX "apparmor"
@@ -230,35 +232,6 @@ static int find_xattr(const char *list, int
list_size, const char *xattr)
 	return 0;
 }

-static int hex_to_bin(char ch)
-{
-	if ((ch >= '0') && (ch <= '9'))
-		return ch - '0';
-	ch = tolower(ch);
-	if ((ch >= 'a') && (ch <= 'f'))
-		return ch - 'a' + 10;
-	return -1;
-}
-
-static int hex2bin(void *dst, const char *src, size_t count)
-{
-	int hi, lo;
-
-	while (count--) {
-		if (*src == ' ')
-			src++;
-
-		hi = hex_to_bin(*src++);
-		lo = hex_to_bin(*src++);
-
-		if ((hi < 0) || (lo < 0))
-			return -1;
-
-		*(uint8_t *)dst++ = (hi << 4) | lo;
-	}
-	return 0;
-}
-
 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]

@@ -1408,58 +1381,6 @@ static int tpm_pcr_read(int idx, uint8_t *pcr, int len)
 	return result;
 }

-#ifdef HAVE_TSSPCRREAD
-static int tpm2_pcrread = 1;
-static int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
-			 int len, char **errmsg)
-{
-	FILE *fp;
-	char pcr[100];	/* may contain an error */
-	char cmd[50];
-	int ret;
-
-	sprintf(cmd, "tsspcrread -halg %s -ha %d -ns 2> /dev/null",
-		algo_name, idx);
-	fp = popen(cmd, "r");
-	if (!fp) {
-		ret = asprintf(errmsg, "popen failed: %s", strerror(errno));
-		if (ret == -1)	/* the contents of errmsg is undefined */
-			*errmsg = NULL;
-		return -1;
-	}
-
-	if (fgets(pcr, sizeof(pcr), fp) == NULL) {
-		ret = asprintf(errmsg, "tsspcrread failed: %s",
-			       strerror(errno));
-		if (ret == -1)	/* the contents of errmsg is undefined */
-			*errmsg = NULL;
-		ret = pclose(fp);
-		return -1;
-	}
-
-	/* get the popen "cmd" return code */
-	ret = pclose(fp);
-
-	/* Treat an unallocated bank as an error */
-	if (!ret && (strlen(pcr) < SHA_DIGEST_LENGTH))
-		ret = -1;
-
-	if (!ret)
-		hex2bin(hwpcr, pcr, len);
-	else
-		*errmsg = strndup(pcr, strlen(pcr) - 1); /* remove newline */
-
-	return ret;
-}
-#else
-static int tpm2_pcrread = 0;
-static int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
-			 int len, char **errmsg)
-{
-	return -1;
-}
-#endif
-
 #define TCG_EVENT_NAME_LEN_MAX	255

 struct template_entry {
@@ -1852,7 +1773,7 @@ static int read_tpm_banks(int num_banks, struct
tpm_bank_info *bank)
 		return 0;

 	/* Any userspace applications available for reading TPM 2.0 PCRs? */
-	if (!tpm2_pcrread) {
+	if (!tpm2_pcr_supported()) {
 		log_debug("Failed to read TPM 2.0 PCRs\n");
 		return 1;
 	}
diff --git a/src/pcr.h b/src/pcr.h
new file mode 100644
index 0000000..79547bd
--- /dev/null
+++ b/src/pcr.h
@@ -0,0 +1,3 @@
+int tpm2_pcr_supported(void);
+int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
+		 int len, char **errmsg);
diff --git a/src/pcr_none.c b/src/pcr_none.c
new file mode 100644
index 0000000..43d053d
--- /dev/null
+++ b/src/pcr_none.c
@@ -0,0 +1,52 @@
+/*
+ * ima-evm-utils - IMA/EVM support utilities
+ *
+ * Copyright (C) 2011 Nokia Corporation
+ * Copyright (C) 2011,2012,2013 Intel Corporation
+ * Copyright (C) 2013,2014 Samsung Electronics
+ *
+ * Authors:
+ * Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
+ *                 <dmitry.kasatkin@intel.com>
+ *                 <d.kasatkin@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ *
+ * File: pcr_none.c
+ *	 PCR reading implementation that always fails
+ */
+
+#include <stdint.h>
+
+int tpm2_pcr_supported(void)
+{
+	return 0;
+}
+
+int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
+		 int len, char **errmsg)
+{
+	return -1;
+}
diff --git a/src/pcr_tss.c b/src/pcr_tss.c
new file mode 100644
index 0000000..da7be2e
--- /dev/null
+++ b/src/pcr_tss.c
@@ -0,0 +1,178 @@
+/*
+ * ima-evm-utils - IMA/EVM support utilities
+ *
+ * Copyright (C) 2011 Nokia Corporation
+ * Copyright (C) 2011,2012,2013 Intel Corporation
+ * Copyright (C) 2013,2014 Samsung Electronics
+ *
+ * Authors:
+ * Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
+ *                 <dmitry.kasatkin@intel.com>
+ *                 <d.kasatkin@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ *
+ * File: pcr_tss.c
+ *	 PCR reading implementation based on Intel TSS2
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include <openssl/sha.h>
+
+#ifdef HAVE_LIBTSS2_ESYS
+#include <tss2/tss2_esys.h>
+
+#ifdef HAVE_LIBTSS2_RC
+#include <tss2/tss2_rc.h>
+#endif
+#endif
+
+int tpm2_pcr_supported(void)
+{
+	return 1;
+}
+
+static int pcr_selections_match(TPML_PCR_SELECTION *a, TPML_PCR_SELECTION *b)
+{
+	if (a->count != b->count)
+		return 0;
+	for (int i = 0; i < a->count; i++) {
+		if (a->pcrSelections[i].hash != b->pcrSelections[i].hash)
+			return 0;
+		if (a->pcrSelections[i].sizeofSelect != b->pcrSelections[i].sizeofSelect)
+			return 0;
+		for (int j = 0; j < a->pcrSelections[i].sizeofSelect; j++) {
+			if (a->pcrSelections[i].pcrSelect[j] != b->pcrSelections[i].pcrSelect[j])
+				return 0;
+		}
+	}
+
+	return 1;
+}
+
+static inline int tpm2_set_errmsg(char **errmsg, const char *message,
TSS2_RC ret)
+{
+#ifdef HAVE_LIBTSS2_RC
+		return asprintf(errmsg, "%s: %s", message, Tss2_RC_Decode(ret));
+#else
+		return asprintf(errmsg, "%s: #%d", message, ret);
+#endif
+}
+
+static TPM2_ALG_ID algo_to_tss2(const char *algo_name)
+{
+	if (!strcmp(algo_name, "sha1"))
+		return TPM2_ALG_SHA1;
+	else if (!strcmp(algo_name, "sha256"))
+		return TPM2_ALG_SHA256;
+
+	return TPM2_ALG_ERROR;
+}
+
+int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
+		 int len, char **errmsg)
+{
+	TSS2_ABI_VERSION abi_version = {
+		.tssCreator = 1,
+		.tssFamily = 2,
+		.tssLevel = 1,
+		.tssVersion = 108,
+	};
+	ESYS_CONTEXT *ctx = NULL;
+	TSS2_RC ret = 0;
+	TPML_PCR_SELECTION *pcr_select_out;
+	TPML_DIGEST *pcr_digests;
+	UINT32 pcr_update_counter;
+
+	TPM2_ALG_ID algid = algo_to_tss2(algo_name);
+	if (algid == TPM2_ALG_ERROR) {
+		ret = asprintf(errmsg, "unsupported tss2 algorithm");
+		if (ret == -1)	/* the contents of errmsg are undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+
+	TPML_PCR_SELECTION pcr_select_in = {
+		.count = 1,
+		.pcrSelections = {
+			{
+				.hash = algid,
+				.sizeofSelect = 3,
+				.pcrSelect = { 0x00, 0x00, 0x00 },
+			}
+		}
+	};
+
+	pcr_select_in.pcrSelections[0].pcrSelect[idx / 8] = (1 << (idx % 8));
+
+	ret = Esys_Initialize(&ctx, NULL, &abi_version);
+	if (ret != TPM2_RC_SUCCESS) {
+		ret = tpm2_set_errmsg(errmsg, "esys initialize failed", ret);
+		if (ret == -1)	/* the contents of errmsg are undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+
+	ret = Esys_PCR_Read(ctx,
+			    ESYS_TR_NONE,
+			    ESYS_TR_NONE,
+			    ESYS_TR_NONE,
+			    &pcr_select_in,
+			    &pcr_update_counter,
+			    &pcr_select_out,
+			    &pcr_digests);
+	Esys_Finalize(&ctx);
+	if (ret != TPM2_RC_SUCCESS) {
+		ret = tpm2_set_errmsg(errmsg, "esys PCR reading failed", ret);
+		if (ret == -1)	/* the contents of errmsg is undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+
+	if (!pcr_selections_match(&pcr_select_in, pcr_select_out)) {
+		Esys_Free(pcr_select_out);
+		Esys_Free(pcr_digests);
+
+		ret = asprintf(errmsg, "TPM returned incorrect PCRs");
+		if (ret == -1)	/* the contents of errmsg are undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+	Esys_Free(pcr_select_out);
+
+	if (pcr_digests->count != 1 || pcr_digests->digests[0].size != len) {
+		Esys_Free(pcr_digests);
+		ret = asprintf(errmsg, "TPM returned incorrect digests");
+		if (ret == -1)	/* the contents of errmsg is undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+
+	memcpy(hwpcr, pcr_digests->digests[0].buffer, len);
+	Esys_Free(pcr_digests);
+	return 0;
+}
diff --git a/src/pcr_tsspcrread.c b/src/pcr_tsspcrread.c
new file mode 100644
index 0000000..f6c6fc5
--- /dev/null
+++ b/src/pcr_tsspcrread.c
@@ -0,0 +1,94 @@
+/*
+ * ima-evm-utils - IMA/EVM support utilities
+ *
+ * Copyright (C) 2011 Nokia Corporation
+ * Copyright (C) 2011,2012,2013 Intel Corporation
+ * Copyright (C) 2013,2014 Samsung Electronics
+ *
+ * Authors:
+ * Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
+ *                 <dmitry.kasatkin@intel.com>
+ *                 <d.kasatkin@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ *
+ * File: pcr_tsspcrread.c
+ *	 PCR reading implementation based on IBM TSS2
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <openssl/sha.h>
+
+#include "utils.h"
+
+int tpm2_pcr_supported(void)
+{
+	return 1;
+}
+
+int tpm2_pcr_read(const char *algo_name, int idx, uint8_t *hwpcr,
+		 int len, char **errmsg)
+{
+	FILE *fp;
+	char pcr[100];	/* may contain an error */
+	char cmd[50];
+	int ret;
+
+	sprintf(cmd, "tsspcrread -halg %s -ha %d -ns 2> /dev/null",
+		algo_name, idx);
+	fp = popen(cmd, "r");
+	if (!fp) {
+		ret = asprintf(errmsg, "popen failed: %s", strerror(errno));
+		if (ret == -1)	/* the contents of errmsg is undefined */
+			*errmsg = NULL;
+		return -1;
+	}
+
+	if (fgets(pcr, sizeof(pcr), fp) == NULL) {
+		ret = asprintf(errmsg, "tsspcrread failed: %s",
+			       strerror(errno));
+		if (ret == -1)	/* the contents of errmsg is undefined */
+			*errmsg = NULL;
+		ret = pclose(fp);
+		return -1;
+	}
+
+	/* get the popen "cmd" return code */
+	ret = pclose(fp);
+
+	/* Treat an unallocated bank as an error */
+	if (!ret && (strlen(pcr) < SHA_DIGEST_LENGTH))
+		ret = -1;
+
+	if (!ret)
+		hex2bin(hwpcr, pcr, len);
+	else
+		*errmsg = strndup(pcr, strlen(pcr) - 1); /* remove newline */
+
+	return ret;
+}
diff --git a/src/utils.c b/src/utils.c
new file mode 100644
index 0000000..22702ed
--- /dev/null
+++ b/src/utils.c
@@ -0,0 +1,32 @@
+#include <stdint.h>
+
+#include "utils.h"
+
+int hex_to_bin(char ch)
+{
+	if ((ch >= '0') && (ch <= '9'))
+		return ch - '0';
+	ch = tolower(ch);
+	if ((ch >= 'a') && (ch <= 'f'))
+		return ch - 'a' + 10;
+	return -1;
+}
+
+int hex2bin(void *dst, const char *src, size_t count)
+{
+	int hi, lo;
+
+	while (count--) {
+		if (*src == ' ')
+			src++;
+
+		hi = hex_to_bin(*src++);
+		lo = hex_to_bin(*src++);
+
+		if ((hi < 0) || (lo < 0))
+			return -1;
+
+		*(uint8_t *)dst++ = (hi << 4) | lo;
+	}
+	return 0;
+}
diff --git a/src/utils.h b/src/utils.h
new file mode 100644
index 0000000..7c0ce15
--- /dev/null
+++ b/src/utils.h
@@ -0,0 +1,5 @@
+#include <ctype.h>
+#include <sys/types.h>
+
+int hex_to_bin(char ch);
+int hex2bin(void *dst, const char *src, size_t count);
-- 
2.24.1

Re: [PATCH v2] ima-evm-utils: Add support for Intel TSS2 for PCR reading

[Mimi Zohar]

On Mon, 2020-02-24 at 15:04 -0800, patrick@puiterwijk.org wrote:
> From: Patrick Uiterwijk <patrick@puiterwijk.org>
> 
> This patch makes it possible to use the Intel TSS2 for getting
> PCR values from the SHA1/SHA256 banks on a TPM2.
> It is somewhat naive as it doesn't use the multi-PCR selection
> that TSS2 is capable of, that is for a future patch.
> 
> Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>

Thanks, Patrick.  There was a missing include in pcr_tsspcrread.c,
which I've included.  This patch is now in the ima-evm-utils next-
testing branch.  I'd appreciate some Review/Test tags for at least the
pcr_tss.c aspect.

IMA support for extending the TPM 2.0 banks with the hash appropriate
algorithm will, hopefully, be upstreamed in Linux 5.8  The new
"boot_aggregate" test calculates a per TPM bank "boot_aggregate"
value.  One of which should match the "boot_aggregate" value in the
IMA measurement list.

Please note that the new "boot_aggregate" test[1] can be run as root,
which accesses the exported TPM securityfs event log, or as a user,
which uses the sample TPM 2.0 sample event log and associated IMA
measurement list.  To calculate the "boot_aggregate" based on the
sample TPM 2.0 event log, requires starting a software TPM and
initializing it based on the TPM event log.  The code currently
initializes the TPM using tsseventextend.

Testing ima-evm-utils support for multiple crypto and TSS packages
requires building a matrix.  As I'm new to travis, the travis code is
in the next-testing-travis branch, but will not be upstreamed at this
point.  To prevent running the "boot_aggregate" test when using the
tpm2-tss, the software TPM is not installed.

Mimi

[1] VERBOSE=1 make check TESTS=boot_aggregate.test
[2] tsseventextend" -tpm -if "${BINARY_BIOS_MEASUREMENTS}" -v