Merge tag 'efi-2022-07-rc7' of https://source.denx.de/u-boot/custodians/u-boot-efi

Pull request efi-2022-07-rc7

UEFI:

* correct verification of signed UEFI binaries

7 files changed, 273 insertions, 30 deletions

diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
index 1c04a7ec5f4..c3f563b2e17 100644
--- a/lib/crypto/Kconfig
+++ b/lib/crypto/Kconfig
@@ -82,4 +82,13 @@ config PKCS7_MESSAGE_PARSER
 config PKCS7_VERIFY
 	bool
 
+config MSCODE_PARSER
+	bool "MS authenticode parser"
+	select ASN1_DECODER
+	select ASN1_COMPILER
+	select OID_REGISTRY
+	help
+	  This option provides support for parsing MicroSoft's Authenticode
+	  in pkcs7 message.
+
 endif # ASYMMETRIC_KEY_TYPE
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index 6792b1d4f00..bec1bc95a65 100644
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -55,3 +55,15 @@ obj-$(CONFIG_$(SPL_)PKCS7_VERIFY) += pkcs7_verify.o
 
 $(obj)/pkcs7_parser.o: $(obj)/pkcs7.asn1.h
 $(obj)/pkcs7.asn1.o: $(obj)/pkcs7.asn1.c $(obj)/pkcs7.asn1.h
+
+#
+# Signed PE binary-wrapped key handling
+#
+obj-$(CONFIG_$(SPL_)MSCODE_PARSER) += mscode.o
+
+mscode-y := \
+	mscode_parser.o \
+	mscode.asn1.o
+
+$(obj)/mscode_parser.o: $(obj)/mscode.asn1.h $(obj)/mscode.asn1.h
+$(obj)/mscode.asn1.o: $(obj)/mscode.asn1.c $(obj)/mscode.asn1.h
diff --git a/lib/crypto/mscode.asn1 b/lib/crypto/mscode.asn1
new file mode 100644
index 00000000000..6d09ba48c41
--- /dev/null
+++ b/lib/crypto/mscode.asn1
@@ -0,0 +1,28 @@
+--- Microsoft individual code signing data blob parser
+---
+--- Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+--- Written by David Howells ([email protected])
+---
+--- This program is free software; you can redistribute it and/or
+--- modify it under the terms of the GNU General Public Licence
+--- as published by the Free Software Foundation; either version
+--- 2 of the Licence, or (at your option) any later version.
+---
+
+MSCode ::= SEQUENCE {
+	type			SEQUENCE {
+		contentType	ContentType,
+		parameters	ANY
+	},
+	content			SEQUENCE {
+		digestAlgorithm	DigestAlgorithmIdentifier,
+		digest		OCTET STRING ({ mscode_note_digest })
+	}
+}
+
+ContentType ::= OBJECT IDENTIFIER ({ mscode_note_content_type })
+
+DigestAlgorithmIdentifier ::= SEQUENCE {
+	algorithm   OBJECT IDENTIFIER ({ mscode_note_digest_algo }),
+	parameters  ANY OPTIONAL
+}
diff --git a/lib/crypto/mscode_parser.c b/lib/crypto/mscode_parser.c
new file mode 100644
index 00000000000..90d5b37a6cf
--- /dev/null
+++ b/lib/crypto/mscode_parser.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Parse a Microsoft Individual Code Signing blob
+ *
+ * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells ([email protected])
+ */
+
+#define pr_fmt(fmt) "MSCODE: "fmt
+#include <linux/kernel.h>
+#ifndef __UBOOT__
+#include <linux/slab.h>
+#endif
+#include <linux/err.h>
+#include <linux/oid_registry.h>
+#include <crypto/pkcs7.h>
+#ifdef __UBOOT__
+#include <crypto/mscode.h>
+#else
+#include "verify_pefile.h"
+#endif
+#include "mscode.asn1.h"
+
+/*
+ * Parse a Microsoft Individual Code Signing blob
+ */
+int mscode_parse(void *_ctx, const void *content_data, size_t data_len,
+		 size_t asn1hdrlen)
+{
+	struct pefile_context *ctx = _ctx;
+
+	content_data -= asn1hdrlen;
+	data_len += asn1hdrlen;
+	pr_devel("Data: %zu [%*ph]\n", data_len, (unsigned)(data_len),
+		 content_data);
+
+	return asn1_ber_decoder(&mscode_decoder, ctx, content_data, data_len);
+}
+
+/*
+ * Check the content type OID
+ */
+int mscode_note_content_type(void *context, size_t hdrlen,
+			     unsigned char tag,
+			     const void *value, size_t vlen)
+{
+	enum OID oid;
+
+	oid = look_up_OID(value, vlen);
+	if (oid == OID__NR) {
+		char buffer[50];
+
+		sprint_oid(value, vlen, buffer, sizeof(buffer));
+		pr_err("Unknown OID: %s\n", buffer);
+		return -EBADMSG;
+	}
+
+	/*
+	 * pesign utility had a bug where it was putting
+	 * OID_msIndividualSPKeyPurpose instead of OID_msPeImageDataObjId
+	 * So allow both OIDs.
+	 */
+	if (oid != OID_msPeImageDataObjId &&
+	    oid != OID_msIndividualSPKeyPurpose) {
+		pr_err("Unexpected content type OID %u\n", oid);
+		return -EBADMSG;
+	}
+
+	return 0;
+}
+
+/*
+ * Note the digest algorithm OID
+ */
+int mscode_note_digest_algo(void *context, size_t hdrlen,
+			    unsigned char tag,
+			    const void *value, size_t vlen)
+{
+	struct pefile_context *ctx = context;
+	char buffer[50];
+	enum OID oid;
+
+	oid = look_up_OID(value, vlen);
+	switch (oid) {
+	case OID_md4:
+		ctx->digest_algo = "md4";
+		break;
+	case OID_md5:
+		ctx->digest_algo = "md5";
+		break;
+	case OID_sha1:
+		ctx->digest_algo = "sha1";
+		break;
+	case OID_sha256:
+		ctx->digest_algo = "sha256";
+		break;
+	case OID_sha384:
+		ctx->digest_algo = "sha384";
+		break;
+	case OID_sha512:
+		ctx->digest_algo = "sha512";
+		break;
+	case OID_sha224:
+		ctx->digest_algo = "sha224";
+		break;
+
+	case OID__NR:
+		sprint_oid(value, vlen, buffer, sizeof(buffer));
+		pr_err("Unknown OID: %s\n", buffer);
+		return -EBADMSG;
+
+	default:
+		pr_err("Unsupported content type: %u\n", oid);
+		return -ENOPKG;
+	}
+
+	return 0;
+}
+
+/*
+ * Note the digest we're guaranteeing with this certificate
+ */
+int mscode_note_digest(void *context, size_t hdrlen,
+		       unsigned char tag,
+		       const void *value, size_t vlen)
+{
+	struct pefile_context *ctx = context;
+
+	ctx->digest = kmemdup(value, vlen, GFP_KERNEL);
+	if (!ctx->digest)
+		return -ENOMEM;
+
+	ctx->digest_len = vlen;
+
+	return 0;
+}
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index e2a1a5a69a2..e3f2402d0e8 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -366,6 +366,7 @@ config EFI_SECURE_BOOT
 	select X509_CERTIFICATE_PARSER
 	select PKCS7_MESSAGE_PARSER
 	select PKCS7_VERIFY
+	select MSCODE_PARSER
 	select EFI_SIGNATURE_SUPPORT
 	help
 	  Select this option to enable EFI secure boot support.
diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
index 96113988850..eaf75a5803d 100644
--- a/lib/efi_loader/efi_image_loader.c
+++ b/lib/efi_loader/efi_image_loader.c
@@ -16,6 +16,7 @@
 #include <malloc.h>
 #include <pe.h>
 #include <sort.h>
+#include <crypto/mscode.h>
 #include <crypto/pkcs7_parser.h>
 #include <linux/err.h>
 
@@ -238,7 +239,7 @@ efi_status_t efi_image_region_add(struct efi_image_regions *regs,
 	int i, j;
 
 	if (regs->num >= regs->max) {
-		EFI_PRINT("%s: no more room for regions\n", __func__);
+		log_err("%s: no more room for regions\n", __func__);
 		return EFI_OUT_OF_RESOURCES;
 	}
 
@@ -263,7 +264,7 @@ efi_status_t efi_image_region_add(struct efi_image_regions *regs,
 		}
 
 		/* new data overlapping registered region */
-		EFI_PRINT("%s: new region already part of another\n", __func__);
+		log_err("%s: new region already part of another\n", __func__);
 		return EFI_INVALID_PARAMETER;
 	}
 
@@ -434,8 +435,8 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
 		bytes_hashed = opt->SizeOfHeaders;
 		align = opt->FileAlignment;
 	} else {
-		EFI_PRINT("%s: Invalid optional header magic %x\n", __func__,
-			  nt->OptionalHeader.Magic);
+		log_err("%s: Invalid optional header magic %x\n", __func__,
+			nt->OptionalHeader.Magic);
 		goto err;
 	}
 
@@ -445,7 +446,7 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
 			    nt->FileHeader.SizeOfOptionalHeader);
 	sorted = calloc(sizeof(IMAGE_SECTION_HEADER *), num_sections);
 	if (!sorted) {
-		EFI_PRINT("%s: Out of memory\n", __func__);
+		log_err("%s: Out of memory\n", __func__);
 		goto err;
 	}
 
@@ -464,7 +465,7 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
 		efi_image_region_add(regs, efi + sorted[i]->PointerToRawData,
 				     efi + sorted[i]->PointerToRawData + size,
 				     0);
-		EFI_PRINT("section[%d](%s): raw: 0x%x-0x%x, virt: %x-%x\n",
+		log_debug("section[%d](%s): raw: 0x%x-0x%x, virt: %x-%x\n",
 			  i, sorted[i]->Name,
 			  sorted[i]->PointerToRawData,
 			  sorted[i]->PointerToRawData + size,
@@ -478,7 +479,7 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
 
 	/* 3. Extra data excluding Certificates Table */
 	if (bytes_hashed + authsz < len) {
-		EFI_PRINT("extra data for hash: %zu\n",
+		log_debug("extra data for hash: %zu\n",
 			  len - (bytes_hashed + authsz));
 		efi_image_region_add(regs, efi + bytes_hashed,
 				     efi + len - authsz, 0);
@@ -487,18 +488,18 @@ bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,
 	/* Return Certificates Table */
 	if (authsz) {
 		if (len < authoff + authsz) {
-			EFI_PRINT("%s: Size for auth too large: %u >= %zu\n",
-				  __func__, authsz, len - authoff);
+			log_err("%s: Size for auth too large: %u >= %zu\n",
+				__func__, authsz, len - authoff);
 			goto err;
 		}
 		if (authsz < sizeof(*auth)) {
-			EFI_PRINT("%s: Size for auth too small: %u < %zu\n",
-				  __func__, authsz, sizeof(*auth));
+			log_err("%s: Size for auth too small: %u < %zu\n",
+				__func__, authsz, sizeof(*auth));
 			goto err;
 		}
 		*auth = efi + authoff;
 		*auth_len = authsz;
-		EFI_PRINT("WIN_CERTIFICATE: 0x%x, size: 0x%x\n", authoff,
+		log_debug("WIN_CERTIFICATE: 0x%x, size: 0x%x\n", authoff,
 			  authsz);
 	} else {
 		*auth = NULL;
@@ -517,6 +518,51 @@ err:
 
 #ifdef CONFIG_EFI_SECURE_BOOT
 /**
+ * efi_image_verify_digest - verify image's message digest
+ * @regs:	Array of memory regions to digest
+ * @msg:	Signature in pkcs7 structure
+ *
+ * @regs contains all the data in a PE image to digest. Calculate
+ * a hash value based on @regs and compare it with a messaged digest
+ * in the content (SpcPeImageData) of @msg's contentInfo.
+ *
+ * Return:	true if verified, false if not
+ */
+static bool efi_image_verify_digest(struct efi_image_regions *regs,
+				    struct pkcs7_message *msg)
+{
+	struct pefile_context ctx;
+	void *hash;
+	int hash_len, ret;
+
+	const void *data;
+	size_t data_len;
+	size_t asn1hdrlen;
+
+	/* get pkcs7's contentInfo */
+	ret = pkcs7_get_content_data(msg, &data, &data_len, &asn1hdrlen);
+	if (ret < 0 || !data)
+		return false;
+
+	/* parse data and retrieve a message digest into ctx */
+	ret = mscode_parse(&ctx, data, data_len, asn1hdrlen);
+	if (ret < 0)
+		return false;
+
+	/* calculate a hash value of PE image */
+	hash = NULL;
+	if (!efi_hash_regions(regs->reg, regs->num, &hash, ctx.digest_algo,
+			      &hash_len))
+		return false;
+
+	/* match the digest */
+	if (ctx.digest_len != hash_len || memcmp(ctx.digest, hash, hash_len))
+		return false;
+
+	return true;
+}
+
+/**
  * efi_image_authenticate() - verify a signature of signed image
  * @efi:	Pointer to image
  * @efi_size:	Size of @efi
@@ -549,7 +595,7 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
 	size_t auth_size;
 	bool ret = false;
 
-	EFI_PRINT("%s: Enter, %d\n", __func__, ret);
+	log_debug("%s: Enter, %d\n", __func__, ret);
 
 	if (!efi_secure_boot_enabled())
 		return true;
@@ -560,7 +606,7 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
 
 	if (!efi_image_parse(new_efi, efi_size, &regs, &wincerts,
 			     &wincerts_len)) {
-		EFI_PRINT("Parsing PE executable image failed\n");
+		log_err("Parsing PE executable image failed\n");
 		goto out;
 	}
 
@@ -569,18 +615,18 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
 	 */
 	db = efi_sigstore_parse_sigdb(u"db");
 	if (!db) {
-		EFI_PRINT("Getting signature database(db) failed\n");
+		log_err("Getting signature database(db) failed\n");
 		goto out;
 	}
 
 	dbx = efi_sigstore_parse_sigdb(u"dbx");
 	if (!dbx) {
-		EFI_PRINT("Getting signature database(dbx) failed\n");
+		log_err("Getting signature database(dbx) failed\n");
 		goto out;
 	}
 
 	if (efi_signature_lookup_digest(regs, dbx, true)) {
-		EFI_PRINT("Image's digest was found in \"dbx\"\n");
+		log_debug("Image's digest was found in \"dbx\"\n");
 		goto out;
 	}
 
@@ -602,12 +648,12 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
 			break;
 
 		if (wincert->dwLength <= sizeof(*wincert)) {
-			EFI_PRINT("dwLength too small: %u < %zu\n",
+			log_debug("dwLength too small: %u < %zu\n",
 				  wincert->dwLength, sizeof(*wincert));
 			continue;
 		}
 
-		EFI_PRINT("WIN_CERTIFICATE_TYPE: 0x%x\n",
+		log_debug("WIN_CERTIFICATE_TYPE: 0x%x\n",
 			  wincert->wCertificateType);
 
 		auth = (u8 *)wincert + sizeof(*wincert);
@@ -617,12 +663,12 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
 				break;
 
 			if (auth_size <= sizeof(efi_guid_t)) {
-				EFI_PRINT("dwLength too small: %u < %zu\n",
+				log_debug("dwLength too small: %u < %zu\n",
 					  wincert->dwLength, sizeof(*wincert));
 				continue;
 			}
 			if (guidcmp(auth, &efi_guid_cert_type_pkcs7)) {
-				EFI_PRINT("Certificate type not supported: %pUs\n",
+				log_debug("Certificate type not supported: %pUs\n",
 					  auth);
 				ret = false;
 				goto out;
@@ -632,19 +678,22 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
 			auth_size -= sizeof(efi_guid_t);
 		} else if (wincert->wCertificateType
 				!= WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
-			EFI_PRINT("Certificate type not supported\n");
+			log_debug("Certificate type not supported\n");
 			ret = false;
 			goto out;
 		}
 
 		msg = pkcs7_parse_message(auth, auth_size);
 		if (IS_ERR(msg)) {
-			EFI_PRINT("Parsing image's signature failed\n");
+			log_err("Parsing image's signature failed\n");
 			msg = NULL;
 			continue;
 		}
 
 		/*
+		 * verify signatures in pkcs7's signedInfos which are
+		 * to authenticate the integrity of pkcs7's contentInfo.
+		 *
 		 * NOTE:
 		 * UEFI specification defines two signature types possible
 		 * in signature database:
@@ -666,23 +715,32 @@ static bool efi_image_authenticate(void *efi, size_t efi_size)
 		/* try black-list first */
 		if (efi_signature_verify_one(regs, msg, dbx)) {
 			ret = false;
-			EFI_PRINT("Signature was rejected by \"dbx\"\n");
+			log_debug("Signature was rejected by \"dbx\"\n");
 			goto out;
 		}
 
 		if (!efi_signature_check_signers(msg, dbx)) {
 			ret = false;
-			EFI_PRINT("Signer(s) in \"dbx\"\n");
+			log_debug("Signer(s) in \"dbx\"\n");
 			goto out;
 		}
 
 		/* try white-list */
-		if (efi_signature_verify(regs, msg, db, dbx)) {
+		if (!efi_signature_verify(regs, msg, db, dbx)) {
+			log_debug("Signature was not verified by \"db\"\n");
+			continue;
+		}
+
+		/*
+		 * now calculate an image's hash value and compare it with
+		 * a messaged digest embedded in pkcs7's contentInfo
+		 */
+		if (efi_image_verify_digest(regs, msg)) {
 			ret = true;
 			continue;
 		}
 
-		EFI_PRINT("Signature was not verified by \"db\"\n");
+		log_debug("Message digest doesn't match\n");
 	}
 
 
@@ -698,7 +756,7 @@ out:
 	if (new_efi != efi)
 		free(new_efi);
 
-	EFI_PRINT("%s: Exit, %d\n", __func__, ret);
+	log_debug("%s: Exit, %d\n", __func__, ret);
 	return ret;
 }
 #else
diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c
index ddac751d128..742d8919402 100644
--- a/lib/efi_loader/efi_signature.c
+++ b/lib/efi_loader/efi_signature.c
@@ -125,8 +125,8 @@ struct pkcs7_message *efi_parse_pkcs7_header(const void *buf,
  *
  * Return:	true on success, false on error
  */
-static bool efi_hash_regions(struct image_region *regs, int count,
-			     void **hash, const char *hash_algo, int *len)
+bool efi_hash_regions(struct image_region *regs, int count,
+		      void **hash, const char *hash_algo, int *len)
 {
 	int ret, hash_len;