Pull request #236: Add code signature verification to HSS Payload Gen…

…erator (SAR 138991)

Merge in FPGA_PFSOC_ES/hart-software-services from next-feature-payload-gen-code-sign-verify to next

* commit 'aec7250e2e1337bb05676e68f9a8f664f3ddb6e4':
  feat(hss-payload-gen): Update README
  feat(hss-payload-gen): Add verify to code signing

tools/hss-payload-generator/Makefile

@@ -75,6 +75,7 @@ SRCS=\
 	generate_payload.c \
 	dump_payload.c \
 	debug_printf.c \
+	verify_payload.c \
 
 OBJS := $(patsubst %.c,$(build_dir)/%.o,$(SRCS))
 

tools/hss-payload-generator/README.md

@@ -1,5 +1,5 @@
 % HSS Payload Generator
-% 2022-09-02
+% 2024-10-14
 
 # Introduction 
 
@@ -21,10 +21,17 @@ To print diagnostics about a pre-existing image, use `-d`:
 
 To enable secure boot authentication (via image signing), use `-p` to specify the location of an X.509 Private Key for the Elliptic Curve P-384 (SECP384r1):
 
-    $ ./hss-payload-generator -c test/config.yaml payload.bin -p /path/to/private.pem
+    $ ./hss-payload-generator -c test/config.yaml -p /path/to/private.pem payload.bin
 
 See the documentation on secure boot authentication for more details.
 
+To verify secure boot code signing, use the `-u` option to specify the location of a DER format Public Key for the Elliptic Curve P-384 (SECP384r1). This option is compatible with either `-p` (during generation) or `-d` during image inspection - for example:
+
+    $ ./hss-payload-generator -p x509-ec-secp384r1-private.pem -c config.yaml -u x509-ec-secp384r1-public.der payload.bin
+    $ ./hss-payload-generator -u x509-ec-secp384r1-public.der -d payload.bin
+
+NOTE: specifically when on Microsoft Windows, ensure that the `payload.bin` argument is at the end of the command line when creating a payload image. We recommend also making the `payload.bin` argument the last argument on Linux.
+
 ## Config File example
 
 First, we can optionally set a name for our image, otherwise one will be created dynamically:

tools/hss-payload-generator/blob_handler.c

@@ -2,7 +2,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/blob_handler.h

@@ -5,7 +5,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/crc32.c

@@ -2,7 +2,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/crc32.h

@@ -5,7 +5,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/debug_printf.c

@@ -2,7 +2,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/debug_printf.h

@@ -5,7 +5,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/dump_payload.c

@@ -2,7 +2,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -43,6 +43,7 @@
 #include "debug_printf.h"
 #include "dump_payload.h"
 #include "crc32.h"
+#include "verify_payload.h"
 
 #define PRV_U (0u)
 #define PRV_S (1u)
@@ -85,7 +86,7 @@ static char const * privModeToString(uint8_t privMode)
 	return result;
 }
 
-void dump_payload(const char *filename_input)
+void dump_payload(const char *filename_input, const char *public_key_filename)
 {
 	printf("opening >>%s<<\n", filename_input);
 	int fdIn = open(filename_input, O_RDONLY);
@@ -94,8 +95,12 @@ void dump_payload(const char *filename_input)
 	size_t fileSize = getFileSize(filename_input);
 
 	struct HSS_BootImage *pBootImage;
+	void *raw_image;
 
-	pBootImage = mmap(NULL, fileSize, PROT_READ, MAP_PRIVATE, fdIn, 0);
+	raw_image = mmap(NULL, fileSize, PROT_READ, MAP_PRIVATE, fdIn, 0);
+	debug_printf(6, "Mapped %d (%x) bytes at %p (to %p)\n", fileSize, fileSize, raw_image, ((uint8_t*)raw_image) + fileSize);
+
+	pBootImage = (struct HSS_BootImage *)raw_image;
 	assert(pBootImage);
 	if (pBootImage == MAP_FAILED) {
 		perror("mmap()");
@@ -236,6 +241,11 @@ void dump_payload(const char *filename_input)
 
 	// skipping binary file array
 
+	if (public_key_filename) {
+		bool result = HSS_Boot_Secure_CheckCodeSigning(raw_image, public_key_filename);
+		printf("Public Key Specified so verifying signature... %s\n\n", result ? "passed" : "failed");
+	}
+
 	munmap(pBootImage, fileSize);
 	close(fdIn);
 }

tools/hss-payload-generator/dump_payload.h

@@ -5,7 +5,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -32,6 +32,6 @@
 #include <stddef.h>
 #include <stdint.h>
 
-void dump_payload(char const * filename);
+void dump_payload(char const * filename, char const * public_key_filename);
 
 #endif

tools/hss-payload-generator/elf_parser.c

@@ -2,7 +2,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/elf_parser.h

@@ -5,7 +5,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/elf_strings.c

@@ -2,7 +2,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/elf_strings.h

@@ -5,7 +5,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *

tools/hss-payload-generator/generate_payload.c

@@ -2,7 +2,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -35,6 +35,7 @@
 #include <libgen.h>
 #include "crc32.h"
 #include "debug_printf.h"
+#include "verify_payload.h"
 
 #include <openssl/ec.h>
 #include <openssl/ecdsa.h>
@@ -118,7 +119,8 @@ static void generate_header(FILE *pFileOut, struct HSS_BootImage *pBootImage) __
 static void generate_chunks(FILE *pFileOut) __attribute__((nonnull));
 static void generate_ziChunks(FILE *pFileOut) __attribute__((nonnull));
 static void generate_blobs(FILE *pFileOut) __attribute__((nonnull));
-static void sign_payload(FILE *pFileOut, char const * const private_key_filename) __attribute__((nonnull(1)));
+static void sign_payload(FILE *pFileOut, char const * const private_key_filename,
+	char const * const public_key_filename) __attribute__((nonnull(1)));
 
 extern struct HSS_BootImage bootImage;
 
@@ -210,7 +212,7 @@ static void generate_chunks(FILE *pFileOut)
 		cumulativeBlobSize += chunkTable[i].chunk.size
 			+ calculate_padding(chunkTable[i].chunk.size, PAD_SIZE);
 
-        	off_t posn = ftello(pFileOut);
+		off_t posn = ftello(pFileOut);
 		debug_printf(4, "\t- Processing chunk %lu (%lu bytes) at file position %lu "
 			"(blob is expected at %lu)\n",
 			i, chunkTable[i].chunk.size, posn, chunkTable[i].chunk.loadAddr);
@@ -259,7 +261,7 @@ static void generate_ziChunks(FILE *pFileOut)
 			+ calculate_padding(sizeof(struct HSS_BootChunkDesc) * (numChunks+1), PAD_SIZE));
 
 	for (size_t i = 0u; i < numZIChunks; i++) {
-        	off_t posn = ftello(pFileOut);
+		off_t posn = ftello(pFileOut);
 		debug_printf(4, "\t- Processing ziChunk %lu (%lu bytes) at file position %lu\n",
 			i, ziChunkTable[i].ziChunk.size, posn);
 
@@ -302,7 +304,7 @@ static void generate_blobs(FILE *pFileOut)
 			+ calculate_padding(sizeof(struct HSS_BootZIChunkDesc) * (numZIChunks +1), PAD_SIZE));
 
 	for (size_t i = 0u; i < numChunks; i++) {
-        	off_t posn = ftello(pFileOut);
+		off_t posn = ftello(pFileOut);
 		debug_printf(4, "\t- Processing blob %lu (%lu bytes) at file position %lu\n",
 			i, chunkTable[i].chunk.size, posn);
 		debug_printf(4, "\t\tCRC32: %x\n",
@@ -323,7 +325,8 @@ static void generate_blobs(FILE *pFileOut)
 	assert(pFileOut);
 }
 
-static void sign_payload(FILE *pFileOut, char const * const private_key_filename)
+static void sign_payload(FILE *pFileOut, char const * const private_key_filename,
+	char const * const public_key_filename)
 {
 	if (private_key_filename) {
 		//
@@ -352,22 +355,29 @@ static void sign_payload(FILE *pFileOut, char const * const private_key_filename
 
 		EVP_PKEY *pPrivKey = PEM_read_PrivateKey(privKeyFileIn, NULL, NULL, NULL);
 		assert(pPrivKey != NULL);
-                fclose(privKeyFileIn);
+		fclose(privKeyFileIn);
 
 		// create the signature by using SHA384 digest and signing with our SECP384r1 private key
 		//
 		EVP_MD_CTX *pCtx = EVP_MD_CTX_new();
 		assert(pCtx != NULL);
 
+		assert(EVP_DigestInit_ex(pCtx, EVP_sha384(), NULL) == 1);
+
+		uint8_t digest[EVP_MAX_MD_SIZE];
+		unsigned int digest_len = 0;
+		assert(EVP_DigestUpdate(pCtx, pEntirePayloadBuffer, bootImage.bootImageLength) == 1);
+		assert(EVP_DigestFinal_ex(pCtx, digest, &digest_len) == 1);
+
 		assert(EVP_DigestSignInit(pCtx, NULL, EVP_sha384(), NULL, pPrivKey) == 1);
+
 		size_t sigLen = 0u;
 		assert(EVP_DigestSign(pCtx, NULL, &sigLen, pEntirePayloadBuffer, bootImage.bootImageLength) == 1);
+
 		unsigned char *pSignatureBuffer = OPENSSL_malloc(sigLen);
 		assert(pSignatureBuffer);
 		assert(EVP_DigestSign(pCtx, pSignatureBuffer, &sigLen, pEntirePayloadBuffer, bootImage.bootImageLength) == 1);
 
-		free(pEntirePayloadBuffer);
-
 		// copy the signature to the boot image header...
 		// OpenSSL will output the signature is in ASN.1 format, as described in
 		// https://datatracker.ietf.org/doc/html/rfc5480
@@ -403,24 +413,26 @@ static void sign_payload(FILE *pFileOut, char const * const private_key_filename
 		ECDSA_SIG *pSig = d2i_ECDSA_SIG(NULL, &sig_ptr, (long)sigLen);
 		assert(pSig != NULL);
 
-                // the signature is in an opaque ECDSA_SIG structure, which contains two
-                // BIGNUMs, r and s.  These are max half the curve size in bytes
-                // => 384 / (8*2) = 48 bytes each... but they may be less, and need to be
-                // zero padded, so extract separately...
-                const BIGNUM *pR = NULL;
-                const BIGNUM *pS = NULL;
-                ECDSA_SIG_get0(pSig, &pR, &pS);
+		// the signature is in an opaque ECDSA_SIG structure, which contains two
+		// BIGNUMs, r and s.  These are max half the curve size in bytes
+		// => 384 / (8*2) = 48 bytes each... but they may be less, and need to be
+		// zero padded, so extract separately...
+		const BIGNUM *pR = NULL;
+		const BIGNUM *pS = NULL;
+		ECDSA_SIG_get0(pSig, &pR, &pS);
 
-                const int rBytes = BN_num_bytes(pR);
-                const int sBytes = BN_num_bytes(pS);
+		const int rBytes = BN_num_bytes(pR);
+		const int sBytes = BN_num_bytes(pS);
 
 		assert(rBytes == sBytes);
 		assert(rBytes == 48);
 
-                memset(pSignatureBuffer, 0, 96);
-                BN_bn2bin(pR, pSignatureBuffer + 48 - rBytes);
-                BN_bn2bin(pS, pSignatureBuffer + 96 - sBytes);
+		memset(pSignatureBuffer, 0, 96);
+		BN_bn2bin(pR, pSignatureBuffer + 48 - rBytes);
+		BN_bn2bin(pS, pSignatureBuffer + 96 - sBytes);
+		//
 
+		memcpy(bootImage.signature.digest, digest, 48u);
 		memcpy(bootImage.signature.ecdsaSig, pSignatureBuffer, 48u);
 		memcpy(bootImage.signature.ecdsaSig + 48u, pSignatureBuffer + 48u, 48u);
 
@@ -435,13 +447,40 @@ static void sign_payload(FILE *pFileOut, char const * const private_key_filename
 		EVP_MD_CTX_free(pCtx);
 		EVP_PKEY_free(pPrivKey);
 		OPENSSL_free(pSignatureBuffer);
+
+		// if a public key was provided, we'll cross-check the signature against it
+		//
+		if (public_key_filename) {
+			// refresh payload from file, as we just rewrote the header to include the signature
+			if (fseek(pFileOut, 0, SEEK_SET) != 0) {
+				perror("fseek()");
+				exit(EXIT_SUCCESS);
+			}
+
+			fileSize = fread((void *)pEntirePayloadBuffer, 1u, bootImage.bootImageLength, pFileOut);
+			assert(fileSize == bootImage.bootImageLength);
+
+			// now perform the cross-check
+			bool result = HSS_Boot_Secure_CheckCodeSigning((struct HSS_BootImage *)pEntirePayloadBuffer, public_key_filename);
+
+			printf("Signature validation using public key ... %s\n\n", result ? "passed":"failed");
+
+		}
+
+		free(pEntirePayloadBuffer);
 	}
 }
 
-void generate_payload(char const * const filename_output, char const * const private_key_filename)
+void generate_payload(char const * const filename_output, char const * const private_key_filename, char const * const public_key_filename)
 {
 	assert(filename_output);
 	printf("Output filename is >>%s<<\n", filename_output);
+	if (private_key_filename) {
+		printf("private_key_filename is >>%s<<\n", private_key_filename);
+	}
+	if (public_key_filename) {
+		printf("public_key_filename is >>%s<<\n", public_key_filename);
+	}
 
 	FILE *pFileOut = fopen(filename_output, "w+");
 	if (!pFileOut) {
@@ -466,7 +505,7 @@ void generate_payload(char const * const filename_output, char const * const pri
 
 	generate_header(pFileOut, &bootImage); // rewrite header for CRC...
 
-	sign_payload(pFileOut, private_key_filename);
+	sign_payload(pFileOut, private_key_filename, public_key_filename);
 
 	if (fclose(pFileOut) != 0) {
 		perror("fclose()");

tools/hss-payload-generator/generate_payload.h

@@ -5,7 +5,7 @@
  *
  * MPFS HSS Embedded Software - tools/hss-payload-generator
  *
- * Copyright 2020-2022 Microchip FPGA Embedded Systems Solutions.
+ * Copyright 2020-2024 Microchip FPGA Embedded Systems Solutions.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -34,7 +34,7 @@
 
 #include "hss_types.h"
 
-void generate_payload(char const * const filename_output, char const * const private_key_filename);
+void generate_payload(char const * const filename_output, char const * const private_key_filename, char const * const public_key_filename);
 void generate_init(void);
 
 size_t generate_add_chunk(struct HSS_BootChunkDesc chunk, void *buffer) __attribute__((nonnull));