On 12/18/19 1:44 AM, AKASHI Takahiro wrote:

In this commit, implemented are a couple of helper functions which will be used to materialize variable authentication as well as image authentication in later patches.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org

include/efi_api.h | 87 +++++ include/efi_loader.h | 72 ++++ lib/efi_loader/Makefile | 1 + lib/efi_loader/efi_signature.c | 584 +++++++++++++++++++++++++++++++++ 4 files changed, 744 insertions(+) create mode 100644 lib/efi_loader/efi_signature.c

diff --git a/include/efi_api.h b/include/efi_api.h index 22396172e15f..47f24fc90873 100644 --- a/include/efi_api.h +++ b/include/efi_api.h @@ -18,6 +18,7 @@

#include <efi.h> #include <charset.h> +#include <pe.h>

#ifdef CONFIG_EFI_LOADER #include <asm/setjmp.h> @@ -307,6 +308,10 @@ struct efi_runtime_services { EFI_GUID(0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, \ 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c)

+#define EFI_IMAGE_SECURITY_DATABASE_GUID \

• EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, \

•  0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f)
  

• #define EFI_FDT_GUID \ EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0)

@@ -1616,4 +1621,86 @@ struct efi_unicode_collation_protocol { #define LOAD_OPTION_CATEGORY_BOOT 0x00000000 #define LOAD_OPTION_CATEGORY_APP 0x00000100

+/* Certificate types in signature database */ +#define EFI_CERT_SHA256_GUID \

• EFI_GUID(0xc1c41626, 0x504c, 0x4092, 0xac, 0xa9, \

•  0x41, 0xf9, 0x36, 0x93, 0x43, 0x28)
  

+#define EFI_CERT_RSA2048_GUID \

• EFI_GUID(0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, \

•  0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6)
  

+#define EFI_CERT_X509_GUID \

• EFI_GUID(0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, \

•  0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72)
  

+#define EFI_CERT_X509_SHA256_GUID \

• EFI_GUID(0x3bd2a492, 0x96c0, 0x4079, 0xb4, 0x20, \

•  0xfc, 0xf9, 0x8e, 0xf1, 0x03, 0xed)
  

+#define EFI_CERT_TYPE_PKCS7_GUID \

• EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \

•  0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7)
  

+/**

• • win_certificate_uefi_guid - A certificate that encapsulates
• • a GUID-specific signature
• • @hdr: Windows certificate header
• • @cert_type: Certificate type
• • @cert_data: Certificate data
• */

+struct win_certificate_uefi_guid {

• WIN_CERTIFICATE hdr;
• efi_guid_t cert_type;
• u8 cert_data[];

+} __attribute__((__packed__));

+/**

• • efi_variable_authentication_2 - A time-based authentication method
• • descriptor
• • This structure describes an authentication information for
• • a variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
• • and should be included as part of a variable's value.
• • Only EFI_CERT_TYPE_PKCS7_GUID is accepted.
• • @time_stamp: Descriptor's time stamp
• • @auth_info: Authentication info
• */

+struct efi_variable_authentication_2 {

• struct efi_time time_stamp;
• struct win_certificate_uefi_guid auth_info;

+} __attribute__((__packed__));

+/**

• • efi_signature_data - A format of signature
• • This structure describes a single signature in signature database.
• • @signature_owner: Signature owner
• • @signature_data: Signature data
• */

+struct efi_signature_data {

• efi_guid_t signature_owner;
• u8 signature_data[];

+} __attribute__((__packed__));

+/**

• • efi_signature_list - A format of signature database
• • This structure describes a list of signatures with the same type.
• • An authenticated variable's value is a concatenation of one or more
• • efi_signature_list's.
• • @signature_type: Signature type
• • @signature_list_size: Size of signature list
• • @signature_header_size: Size of signature header
• • @signature_size: Size of signature
• */

+struct efi_signature_list {

• efi_guid_t signature_type;
• u32 signature_list_size;
• u32 signature_header_size;
• u32 signature_size;

+/* u8 signature_header[signature_header_size]; */ +/* struct efi_signature_data signatures[...][signature_size]; */ +} __attribute__((__packed__));

• #endif

diff --git a/include/efi_loader.h b/include/efi_loader.h index 381da80cdce0..3ca68f9bbb6e 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -21,6 +21,7 @@ static inline int guidcmp(const void *g1, const void *g2) #if CONFIG_IS_ENABLED(EFI_LOADER)

#include <linux/list.h> +#include <linux/oid_registry.h>

/* Maximum number of configuration tables */ #define EFI_MAX_CONFIGURATION_TABLES 16 @@ -169,6 +170,11 @@ extern const efi_guid_t efi_guid_hii_config_routing_protocol; extern const efi_guid_t efi_guid_hii_config_access_protocol; extern const efi_guid_t efi_guid_hii_database_protocol; extern const efi_guid_t efi_guid_hii_string_protocol; +/* GUIDs for authentication */ +extern const efi_guid_t efi_guid_image_security_database; +extern const efi_guid_t efi_guid_sha256; +extern const efi_guid_t efi_guid_cert_x509; +extern const efi_guid_t efi_guid_cert_x509_sha256;

extern unsigned int __efi_runtime_start, __efi_runtime_stop; extern unsigned int __efi_runtime_rel_start, __efi_runtime_rel_stop; @@ -650,6 +656,72 @@ void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data); unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data); efi_status_t efi_bootmgr_load(efi_handle_t *handle);

+#ifdef CONFIG_EFI_SECURE_BOOT

This constraint surrounds the whole code. So, please, move the constraint to the Makefile.

Best regards

Heinrich

+#include <image.h>

+/**

• • efi_image_regions - A list of memory regions
• • @max: Maximum number of regions
• • @num: Number of regions
• • @reg: array of regions
• */

+struct efi_image_regions {

• int max;
• int num;
• struct image_region reg[];

+};

+/**

• • efi_sig_data - A decoded data of struct efi_signature_data
• • This structure represents an internal form of signature in
• • signature database. A listed list may represent a signature list.
• • @next: Pointer to next entry
• • @onwer: Signature owner
• • @data: Pointer to signature data
• • @size: Size of signature data
• */

+struct efi_sig_data {

• struct efi_sig_data *next;
• efi_guid_t owner;
• void *data;
• size_t size;

+};

+/**

• • efi_signature_store - A decoded data of signature database
• • This structure represents an internal form of signature database.
• • @next: Pointer to next entry
• • @sig_type: Signature type
• • @sig_data_list: Pointer to signature list
• */

+struct efi_signature_store {

• struct efi_signature_store *next;
• efi_guid_t sig_type;
• struct efi_sig_data *sig_data_list;

+};

+struct x509_certificate; +struct pkcs7_message;

+bool efi_signature_verify_cert(struct x509_certificate *cert,

• 	       struct efi_signature_store *dbx);
  

+bool efi_signature_verify_signers(struct pkcs7_message *msg,

• 		  struct efi_signature_store *dbx);
  

+bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs,

• 		     struct pkcs7_message *msg,
  

• 		  struct efi_signature_store *db,
  

• 		  struct x509_certificate **cert);
  

+efi_status_t efi_image_region_add(struct efi_image_regions *regs,

• 		  const void *start, const void *end,
  

• 		  int nocheck);
  

+#endif /* CONFIG_EFI_SECURE_BOOT */

• #else /* CONFIG_IS_ENABLED(EFI_LOADER) */

  /* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */

diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile index 7db406028618..3ffbfe78a46b 100644 --- a/lib/efi_loader/Makefile +++ b/lib/efi_loader/Makefile @@ -42,3 +42,4 @@ obj-$(CONFIG_PARTITIONS) += efi_disk.o obj-$(CONFIG_NET) += efi_net.o obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o +obj-y += efi_signature.o diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c new file mode 100644 index 000000000000..823d3311e010 --- /dev/null +++ b/lib/efi_loader/efi_signature.c @@ -0,0 +1,584 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*

• • Copyright (c) 2018 Patrick Wildt patrick@blueri.se
• • Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro
• */

+#include <common.h> +#include <charset.h> +#include <efi_loader.h> +#include <image.h> +#include <hexdump.h> +#include <malloc.h> +#include <pe.h> +#include <linux/compat.h> +#include <linux/oid_registry.h> +#include <u-boot/rsa.h> +#include <u-boot/sha256.h> +/*

• • avoid duplicated inclusion:
• • #include "../lib/crypto/x509_parser.h"
• */

+#include "../lib/crypto/pkcs7_parser.h"

+const efi_guid_t efi_guid_image_security_database =

• EFI_IMAGE_SECURITY_DATABASE_GUID;
  

+const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID;

+#ifdef CONFIG_EFI_SECURE_BOOT

+/**

• • efi_hash_regions - calculate a hash value
• • @regs: List of regions
• • @hash: Pointer to a pointer to buffer holding a hash value
• • @size: Size of buffer to be returned
• • Calculate a sha256 value of @regs and return a value in @hash.
• • Return: true on success, false on error
• */

+static bool efi_hash_regions(struct efi_image_regions *regs, void **hash,

• 	     size_t *size)
  

+{

• *size = 0;
• *hash = calloc(1, SHA256_SUM_LEN);
• if (!*hash) {

• debug("Out of memory\n");
  

• return false;
  

• }
• *size = SHA256_SUM_LEN;
• hash_calculate("sha256", regs->reg, regs->num, *hash);

+#ifdef DEBUG

• debug("hash calculated:\n");
• print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1,

•        *hash, SHA256_SUM_LEN, false);
  

+#endif

• return true;

+}

+/**

• • efi_hash_msg_content - calculate a hash value of contentInfo
• • @msg: Signature
• • @hash: Pointer to a pointer to buffer holding a hash value
• • @size: Size of buffer to be returned
• • Calculate a sha256 value of contentInfo in @msg and return a value in @hash.
• • Return: true on success, false on error
• */

+static bool efi_hash_msg_content(struct pkcs7_message *msg, void **hash,

• 		 size_t *size)
  

+{

• struct image_region regtmp;
• *size = 0;
• *hash = calloc(1, SHA256_SUM_LEN);
• if (!*hash) {

• debug("Out of memory\n");
  

• free(msg);
  

• return false;
  

• }
• *size = SHA256_SUM_LEN;
• regtmp.data = msg->data;
• regtmp.size = msg->data_len;
• hash_calculate("sha256", &regtmp, 1, *hash);

+#ifdef DEBUG

• debug("hash calculated based on contentInfo:\n");
• print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1,

•        *hash, SHA256_SUM_LEN, false);
  

+#endif

• return true;

+}

+/**

• • efi_signature_verify - verify a signature with a certificate
• • @regs: List of regions to be authenticated
• • @signed_info: Pointer to PKCS7's signed_info
• • @cert: x509 certificate
• • Signature pointed to by @signed_info against image pointed to by @regs
• • is verified by a certificate pointed to by @cert.
• • @signed_info holds a signature, including a message digest which is to be
• • compared with a hash value calculated from @regs.
• • Return: true if signature is verified, false if not
• */

+static bool efi_signature_verify(struct efi_image_regions *regs,

• 		 struct pkcs7_message *msg,
  

• 		 struct pkcs7_signed_info *ps_info,
  

• 		 struct x509_certificate *cert)
  

+{

• struct image_sign_info info;
• struct image_region regtmp[2];
• void *hash;
• size_t size;
• char c;
• bool verified;
• debug("%s: Enter, %p, %p, %p(issuer: %s, subject: %s)\n", __func__,

•      regs, ps_info, cert, cert->issuer, cert->subject);
  

• verified = false;
• memset(&info, '\0', sizeof(info));
• info.padding = image_get_padding_algo("pkcs-1.5");
• /*

• * Note: image_get_[checksum|crypto]_algo takes an string
  

• * argument like "<checksum>,<crypto>"
  

• * TODO: support other hash algorithms
  

• */
  

• if (!strcmp(ps_info->sig->hash_algo, "sha1")) {

• info.checksum = image_get_checksum_algo("sha1,rsa2048");
  

• info.name = "sha1,rsa2048";
  

• } else if (!strcmp(ps_info->sig->hash_algo, "sha256")) {

• info.checksum = image_get_checksum_algo("sha256,rsa2048");
  

• info.name = "sha256,rsa2048";
  

• } else {

• debug("unknown msg digest algo: %s\n", ps_info->sig->hash_algo);
  

• goto out;
  

• }
• info.crypto = image_get_crypto_algo(info.name);
• info.key = cert->pub->key;
• info.keylen = cert->pub->keylen;
• /* verify signature */
• debug("%s: crypto: %s, signature len:%x\n", __func__,

•      info.name, ps_info->sig->s_size);
  

• if (ps_info->aa_set & (1UL << sinfo_has_message_digest)) {

• debug("%s: RSA verify authentication attribute\n", __func__);
  

• /*
  

•  * NOTE: This path will be executed only for
  

•  * PE image authentication
  

•  */
  

• /* check if hash matches digest first */
  

• debug("checking msg digest first, len:0x%x\n",
  

•       ps_info->msgdigest_len);
  

+#ifdef DEBUG

• debug("hash in database:\n");
  

• print_hex_dump("    ", DUMP_PREFIX_OFFSET, 16, 1,
  

• 	       ps_info->msgdigest, ps_info->msgdigest_len,
  

• 	       false);
  

+#endif

• /* against contentInfo first */
  

• if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) ||
  

• 		/* for signed image */
  

•     efi_hash_regions(regs, &hash, &size)) {
  

• 		/* for authenticated variable */
  

• 	if (ps_info->msgdigest_len != size ||
  

• 	    memcmp(hash, ps_info->msgdigest, size)) {
  

• 		debug("Digest doesn't match\n");
  

• 		free(hash);
  

• 		goto out;
  

• 	}
  

• 	free(hash);
  

• } else {
  

• 	debug("Digesting image failed\n");
  

• 	goto out;
  

• }
  

• /* against digest */
  

• c = 0x31;
  

• regtmp[0].data = &c;
  

• regtmp[0].size = 1;
  

• regtmp[1].data = ps_info->authattrs;
  

• regtmp[1].size = ps_info->authattrs_len;
  

• if (!rsa_verify(&info, regtmp, 2,
  

• 		ps_info->sig->s, ps_info->sig->s_size))
  

• 	verified = true;
  

• } else {

• debug("%s: RSA verify content data\n", __func__);
  

• /* against all data */
  

• if (!rsa_verify(&info, regs->reg, regs->num,
  

• 		ps_info->sig->s, ps_info->sig->s_size))
  

• 	verified = true;
  

• }

+out:

• debug("%s: Exit, verified: %d\n", __func__, verified);
• return verified;

+}

+/**

• • efi_signature_verify_with_list - verify a signature with signature list
• • @regs: List of regions to be authenticated
• • @msg: Signature
• • @signed_info: Pointer to PKCS7's signed_info
• • @siglist: Signature list for certificates
• • @valid_cert: x509 certificate that verifies this signature
• • Signature pointed to by @signed_info against image pointed to by @regs
• • is verified by signature list pointed to by @siglist.
• • Signature database is a simple concatenation of one or more
• • signature list(s).
• • Return: true if signature is verified, false if not
• */

+static +bool efi_signature_verify_with_list(struct efi_image_regions *regs,

• 		    struct pkcs7_message *msg,
  

• 		    struct pkcs7_signed_info *signed_info,
  

• 		    struct efi_signature_store *siglist,
  

• 		    struct x509_certificate **valid_cert)
  

+{

• struct x509_certificate *cert;
• struct efi_sig_data *sig_data;
• bool verified = false;
• debug("%s: Enter, %p, %p, %p, %p\n", __func__,

•      regs, signed_info, siglist, valid_cert);
  

• if (!signed_info) {

• void *hash;
  

• size_t size;
  

• debug("%s: unsigned image\n", __func__);
  

• /*
  

•  * verify based on calculated hash value
  

•  * TODO: support other hash algorithms
  

•  */
  

• if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) {
  

• 	debug("Digest algorithm is not supported: %pUl\n",
  

• 	      &siglist->sig_type);
  

• 	goto out;
  

• }
  

• if (!efi_hash_regions(regs, &hash, &size)) {
  

• 	debug("Digesting unsigned image failed\n");
  

• 	goto out;
  

• }
  

• /* go through the list */
  

• for (sig_data = siglist->sig_data_list; sig_data;
  

•      sig_data = sig_data->next) {
  

+#ifdef DEBUG

• 	debug("Msg digest in database:\n");
  

• 	print_hex_dump("    ", DUMP_PREFIX_OFFSET, 16, 1,
  

• 		       sig_data->data, sig_data->size, false);
  

+#endif

• 	if ((sig_data->size == size) &&
  

• 	    !memcmp(sig_data->data, hash, size)) {
  

• 		verified = true;
  

• 		free(hash);
  

• 		goto out;
  

• 	}
  

• }
  

• free(hash);
  

• goto out;
  

• }
• debug("%s: signed image\n", __func__);
• if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) {

• debug("Signature type is not supported: %pUl\n",
  

•       &siglist->sig_type);
  

• goto out;
  

• }
• /* go through the list */
• for (sig_data = siglist->sig_data_list; sig_data;

•     sig_data = sig_data->next) {
  

• /* TODO: support owner check based on policy */
  

• cert = x509_cert_parse(sig_data->data, sig_data->size);
  

• if (IS_ERR(cert)) {
  

• 	debug("Parsing x509 certificate failed\n");
  

• 	goto out;
  

• }
  

• verified = efi_signature_verify(regs, msg, signed_info, cert);
  

• if (verified) {
  

• 	if (valid_cert)
  

• 		*valid_cert = cert;
  

• 	else
  

• 		x509_free_certificate(cert);
  

• 	break;
  

• } else {
  

• 	x509_free_certificate(cert);
  

• }
  

• }

+out:

• debug("%s: Exit, verified: %d\n", __func__, verified);
• return verified;

+}

+/**

• • efi_signature_verify_with_sigdb - verify a signature with db
• • @regs: List of regions to be authenticated
• • @msg: Signature
• • @db: Signature database for trusted certificates
• • @cert: x509 certificate that verifies this signature
• • Signature pointed to by @msg against image pointed to by @regs
• • is verified by signature database pointed to by @db.
• • Return: true if signature is verified, false if not
• */

+bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs,

• 		     struct pkcs7_message *msg,
  

• 		     struct efi_signature_store *db,
  

• 		     struct x509_certificate **cert)
  

+{

• struct pkcs7_signed_info *info;
• struct efi_signature_store *siglist;
• bool verified = false;
• debug("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, cert);
• if (!db)

• goto out;
  

• if (!db->sig_data_list)

• goto out;
  

• /* for unsigned image */
• if (!msg) {

• debug("%s: Verify unsigned image with db\n", __func__);
  

• for (siglist = db; siglist; siglist = siglist->next)
  

• 	if (efi_signature_verify_with_list(regs, NULL, NULL,
  

• 					   siglist, cert)) {
  

• 		verified = true;
  

• 		goto out;
  

• 	}
  

• goto out;
  

• }
• /* for signed image or variable */
• debug("%s: Verify signed image with db\n", __func__);
• for (info = msg->signed_infos; info; info = info->next) {

• debug("Signed Info: digest algo: %s, pkey algo: %s\n",
  

•       info->sig->hash_algo, info->sig->pkey_algo);
  

• for (siglist = db; siglist; siglist = siglist->next) {
  

• 	if (efi_signature_verify_with_list(regs, msg, info,
  

• 					   siglist, cert)) {
  

• 		verified = true;
  

• 		goto out;
  

• 	}
  

• }
  

• }

+out:

• debug("%s: Exit, verified: %d\n", __func__, verified);
• return verified;

+}

+/**

• • efi_search_siglist - search signature list for a certificate
• • @cert: x509 certificate
• • @siglist: Signature list
• • @revoc_time: Pointer to buffer for revocation time
• • Search signature list pointed to by @siglist and find a certificate
• • pointed to by @cert.
• • If found, revocation time that is specified in signature database is
• • returned in @revoc_time.
• • Return: true if certificate is found, false if not
• */

+static bool efi_search_siglist(struct x509_certificate *cert,

• 	       struct efi_signature_store *siglist,
  

• 	       time64_t *revoc_time)
  

+{

• struct image_region reg[1];
• void *hash = NULL, *msg = NULL;
• struct efi_sig_data *sig_data;
• bool found = false;
• /* can be null */
• if (!siglist->sig_data_list)

• return false;
  

• if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) {

• /* TODO: other hash algos */
  

• debug("Certificate's digest type is not supported: %pUl\n",
  

•       &siglist->sig_type);
  

• goto out;
  

• }
• /* calculate hash of TBSCertificate */
• msg = calloc(1, SHA256_SUM_LEN);
• if (!msg) {

• debug("Out of memory\n");
  

• goto out;
  

• }
• hash = calloc(1, SHA256_SUM_LEN);
• if (!hash) {

• debug("Out of memory\n");
  

• goto out;
  

• }
• reg[0].data = cert->tbs;
• reg[0].size = cert->tbs_size;
• hash_calculate("sha256", reg, 1, msg);
• /* go through signature list */
• for (sig_data = siglist->sig_data_list; sig_data;

•     sig_data = sig_data->next) {
  

• /*
  

•  * struct efi_cert_x509_sha256 {
  

•  *	u8 tbs_hash[256/8];
  

•  *	time64_t revocation_time;
  

•  * };
  

•  */
  

• if ((sig_data->size == SHA256_SUM_LEN) &&
  

•     !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) {
  

• 	memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN,
  

• 	       sizeof(*revoc_time));
  

• 	found = true;
  

• 	goto out;
  

• }
  

• }

+out:

• free(hash);
• free(msg);
• return found;

+}

+/**

• • efi_signature_verify_cert - verify a certificate with dbx
• • @cert: x509 certificate
• • @dbx: Signature database
• • Search signature database pointed to by @dbx and find a certificate
• • pointed to by @cert.
• • This function is expected to be used against "dbx".
• • Return: true if a certificate is not rejected, false otherwise.
• */

+bool efi_signature_verify_cert(struct x509_certificate *cert,

• 	       struct efi_signature_store *dbx)
  

+{

• struct efi_signature_store *siglist;
• time64_t revoc_time;
• bool found = false;
• debug("%s: Enter, %p, %p\n", __func__, dbx, cert);
• if (!cert)

• return false;
  

• for (siglist = dbx; siglist; siglist = siglist->next) {

• if (efi_search_siglist(cert, siglist, &revoc_time)) {
  

• 	/* TODO */
  

• 	/* compare signing time with revocation time */
  

• 	found = true;
  

• 	break;
  

• }
  

• }
• debug("%s: Exit, verified: %d\n", __func__, !found);
• return !found;

+}

+/**

• • efi_signature_verify_signers - verify signers' certificates with dbx
• • @msg: Signature
• • @dbx: Signature database
• • Determine if any of signers' certificates in @msg may be verified
• • by any of certificates in signature database pointed to by @dbx.
• • This function is expected to be used against "dbx".
• • Return: true if none of certificates is rejected, false otherwise.
• */

+bool efi_signature_verify_signers(struct pkcs7_message *msg,

• 		  struct efi_signature_store *dbx)
  

+{

• struct pkcs7_signed_info *info;
• bool found = false;
• debug("%s: Enter, %p, %p\n", __func__, msg, dbx);
• if (!msg)

• goto out;
  

• for (info = msg->signed_infos; info; info = info->next) {

• if (info->signer &&
  

•     !efi_signature_verify_cert(info->signer, dbx)) {
  

• 	found = true;
  

• 	goto out;
  

• }
  

• }

+out:

• debug("%s: Exit, verified: %d\n", __func__, !found);
• return !found;

+}

+/**

• • efi_image_region_add - add an entry of region
• • @regs: Pointer to array of regions
• • @start: Start address of region
• • @end: End address of region
• • @nocheck: flag against overlapped regions
• • Take one entry of region [@start, @end] and append it to the list
• • pointed to by @regs. If @nocheck is false, overlapping among entries
• • will be checked first.
• • Return: 0 on success, status code (negative) on error
• */

+efi_status_t efi_image_region_add(struct efi_image_regions *regs,

• 		  const void *start, const void *end,
  

• 		  int nocheck)
  

+{

• struct image_region *reg;
• int i, j;
• if (regs->num >= regs->max) {

• debug("%s: no more room for regions\n", __func__);
  

• return EFI_OUT_OF_RESOURCES;
  

• }
• if (end < start)

• return EFI_INVALID_PARAMETER;
  

• for (i = 0; i < regs->num; i++) {

• reg = &regs->reg[i];
  

• if (nocheck)
  

• 	continue;
  

• if (start > reg->data + reg->size)
  

• 	continue;
  

• if ((start >= reg->data && start < reg->data + reg->size) ||
  

•     (end > reg->data && end < reg->data + reg->size)) {
  

• 	debug("%s: new region already part of another\n",
  

• 	      __func__);
  

• 	return EFI_INVALID_PARAMETER;
  

• }
  

• if (start < reg->data && end < reg->data + reg->size) {
  

• 	for (j = regs->num - 1; j >= i; j--)
  

• 		memcpy(&regs->reg[j], &regs->reg[j + 1],
  

• 		       sizeof(*reg));
  

• 	break;
  

• }
  

• }
• reg = &regs->reg[i];
• reg->data = start;
• reg->size = end - start;
• regs->num++;
• return EFI_SUCCESS;

+} +#endif /* CONFIG_EFI_SECURE_BOOT */

On Wed, Jan 15, 2020 at 01:13:36AM +0100, Heinrich Schuchardt wrote:

On 1/15/20 12:43 AM, Heinrich Schuchardt wrote:

...

On 12/18/19 1:44 AM, AKASHI Takahiro wrote:

(snip)

...

...

diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c new file mode 100644 index 000000000000..823d3311e010 --- /dev/null +++ b/lib/efi_loader/efi_signature.c @@ -0,0 +1,584 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*

• • Copyright (c) 2018 Patrick Wildt patrick@blueri.se
• • Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro
• */

+#include <common.h> +#include <charset.h> +#include <efi_loader.h> +#include <image.h> +#include <hexdump.h> +#include <malloc.h> +#include <pe.h> +#include <linux/compat.h> +#include <linux/oid_registry.h> +#include <u-boot/rsa.h> +#include <u-boot/sha256.h> +/*

• • avoid duplicated inclusion:
• • #include "../lib/crypto/x509_parser.h"
• */

+#include "../lib/crypto/pkcs7_parser.h"

+const efi_guid_t efi_guid_image_security_database = +        EFI_IMAGE_SECURITY_DATABASE_GUID; +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID;

+#ifdef CONFIG_EFI_SECURE_BOOT

This is the #ifdef to move to the Makefile. In the previous mail I got into the wrong line.

No. As you can see, those guids may also be referred to by other files (see efi_variable.c and cmd/nvedit_efi.c) even in !EFI_SECURE_BOOT case, and I think that this file is best fit for them.

-Takahiro Akashi

Best regards

Heinrich

On Fri, Jan 17, 2020 at 06:37:39AM +0100, Heinrich Schuchardt wrote:

On 1/17/20 3:20 AM, AKASHI Takahiro wrote:

...

On Wed, Jan 15, 2020 at 01:13:36AM +0100, Heinrich Schuchardt wrote:

...

On 1/15/20 12:43 AM, Heinrich Schuchardt wrote:

...

On 12/18/19 1:44 AM, AKASHI Takahiro wrote:

(snip)

...

...

...

diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c new file mode 100644 index 000000000000..823d3311e010 --- /dev/null +++ b/lib/efi_loader/efi_signature.c @@ -0,0 +1,584 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*

• • Copyright (c) 2018 Patrick Wildt patrick@blueri.se
• • Copyright (c) 2019 Linaro Limited, Author: AKASHI Takahiro
• */

+#include <common.h> +#include <charset.h> +#include <efi_loader.h> +#include <image.h> +#include <hexdump.h> +#include <malloc.h> +#include <pe.h> +#include <linux/compat.h> +#include <linux/oid_registry.h> +#include <u-boot/rsa.h> +#include <u-boot/sha256.h> +/*

• • avoid duplicated inclusion:
• • #include "../lib/crypto/x509_parser.h"
• */

+#include "../lib/crypto/pkcs7_parser.h"

+const efi_guid_t efi_guid_image_security_database = +        EFI_IMAGE_SECURITY_DATABASE_GUID; +const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; +const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID; +const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; +const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID;

+#ifdef CONFIG_EFI_SECURE_BOOT

This is the #ifdef to move to the Makefile. In the previous mail I got into the wrong line.

No. As you can see, those guids may also be referred to by other files (see efi_variable.c and cmd/nvedit_efi.c) even in !EFI_SECURE_BOOT case, and I think that this file is best fit for them.

I cannot find any of these guids in any other C file after applying all patches from

??? Did you look for efi_guid_image_security_database in efi_variable.c and cmd/nvedit_efi.c?

-Takahiro Akashi

https://patchwork.ozlabs.org/project/uboot/list/?series=&submitter=61166...

git grep -n efi_guid_sha256 include/efi_loader.h:185:extern const efi_guid_t efi_guid_sha256; lib/efi_loader/efi_signature.c:26:const efi_guid_t efi_guid_sha256 = EFI_CERT_SHA256_GUID; lib/efi_loader/efi_signature.c:252: if (guidcmp(&siglist->sig_type, &efi_guid_sha256)) {

lib/efi_loader/efi_signature.c:27:const efi_guid_t efi_guid_cert_rsa2048 = EFI_CERT_RSA2048_GUID;

git grep -n efi_guid_cert_x509 include/efi_loader.h:186:extern const efi_guid_t efi_guid_cert_x509; include/efi_loader.h:187:extern const efi_guid_t efi_guid_cert_x509_sha256; lib/efi_loader/efi_signature.c:28:const efi_guid_t efi_guid_cert_x509 = EFI_CERT_X509_GUID; lib/efi_loader/efi_signature.c:29:const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; lib/efi_loader/efi_signature.c:283: if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { lib/efi_loader/efi_signature.c:406: if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) {

include/efi_loader.h:187:extern const efi_guid_t efi_guid_cert_x509_sha256; lib/efi_loader/efi_signature.c:29:const efi_guid_t efi_guid_cert_x509_sha256 = EFI_CERT_X509_SHA256_GUID; lib/efi_loader/efi_signature.c:406: if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509_sha256)) {

Best regards

Heinrich

On Wed, Jan 08, 2020 at 11:54:26PM +0100, Heinrich Schuchardt wrote:

On 12/18/19 1:45 AM, AKASHI Takahiro wrote:

...

With this commit, EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS is supported for authenticated variables and the system secure state will transfer between setup mode and user mode as UEFI specification section 32.3 describes.

Internally, authentication data is stored as part of authenticated variable's value. It is nothing but a pkcs7 message (but we need some wrapper, see efi_variable_parse_signature()) and will be validated by efi_variable_authenticate(), hence efi_signature_verify_with_db().

Associated time value will be encoded in "{...,time=...}" along with other UEFI variable's attributes.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org

include/efi_loader.h | 3 + lib/efi_loader/efi_variable.c | 665 ++++++++++++++++++++++++++++------ 2 files changed, 564 insertions(+), 104 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h index 3b3618e0be24..1f88caf86709 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -175,6 +175,7 @@ extern const efi_guid_t efi_guid_image_security_database; extern const efi_guid_t efi_guid_sha256; extern const efi_guid_t efi_guid_cert_x509; extern const efi_guid_t efi_guid_cert_x509_sha256; +extern const efi_guid_t efi_guid_cert_type_pkcs7;

extern unsigned int __efi_runtime_start, __efi_runtime_stop; extern unsigned int __efi_runtime_rel_start, __efi_runtime_rel_stop; @@ -723,6 +724,8 @@ efi_status_t efi_image_region_add(struct efi_image_regions *regs,

void efi_sigstore_free(struct efi_signature_store *sigstore); struct efi_signature_store *efi_sigstore_parse_sigdb(u16 *name);

+bool efi_secure_boot_enabled(void); #endif /* CONFIG_EFI_SECURE_BOOT */

#else /* CONFIG_IS_ENABLED(EFI_LOADER) */ diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c index 46f35bc60ba0..171b4abb4c58 100644 --- a/lib/efi_loader/efi_variable.c +++ b/lib/efi_loader/efi_variable.c @@ -10,7 +10,13 @@ #include <env_internal.h> #include <hexdump.h> #include <malloc.h> +#include <rtc.h> #include <search.h> +#include <linux/compat.h> +#include "../lib/crypto/pkcs7_parser.h"

+const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID; +static bool efi_secure_boot;

#define READ_ONLY BIT(31)

@@ -107,7 +113,7 @@ static const char *prefix(const char *str, const char *prefix)

• @attrp: pointer to UEFI attributes
• Return: pointer to remainder of U-Boot variable value

*/ -static const char *parse_attr(const char *str, u32 *attrp) +static const char *parse_attr(const char *str, u32 *attrp, u64 *timep) { u32 attr = 0; char sep = '{'; @@ -130,6 +136,12 @@ static const char *parse_attr(const char *str, u32 *attrp) attr |= EFI_VARIABLE_BOOTSERVICE_ACCESS; } else if ((s = prefix(str, "run"))) { attr |= EFI_VARIABLE_RUNTIME_ACCESS;

• } else if ((s = prefix(str, "time="))) {
  

• 	attr |= EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
  

• 	hex2bin((u8 *)timep, s, sizeof(*timep));
  

• 	s += sizeof(*timep) * 2;
  

• } else if (*str == '}') {
  

• 	break;
  

  } else { printf("invalid attribute: %s\n", str); break;

@@ -147,48 +159,291 @@ static const char *parse_attr(const char *str, u32 *attrp) }

/**

• • efi_get_variable() - retrieve value of a UEFI variable

• • efi_secure_boot_enabled - return if secure boot is enabled or not

• • This function implements the GetVariable runtime service.

• • Return: true if enabled, false if disabled
• */

+bool efi_secure_boot_enabled(void) +{

• return efi_secure_boot;

+}

+#ifdef CONFIG_EFI_SECURE_BOOT +static u8 pkcs7_hdr[] = {

• /* SEQUENCE */
• 0x30, 0x82, 0x05, 0xc7,
• /* OID: pkcs7-signedData */
• 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x02,
• /* Context Structured? */
• 0xa0, 0x82, 0x05, 0xb8,

+};

+/**

• • efi_variable_parse_signature - parse a signature in variable
• • @buf: Pointer to variable's value
• • @buflen: Length of @buf

• • See the Unified Extensible Firmware Interface (UEFI) specification for
• • details.

• • Parse a signature embedded in variable's value and instantiate
• • a pkcs7_message structure. Since pkcs7_parse_message() accepts only
• • pkcs7's signedData, some header needed be prepended for correctly
• • parsing authentication data, particularly for variable's.

• • @variable_name: name of the variable
• • @vendor: vendor GUID
• • @attributes: attributes of the variable
• • @data_size: size of the buffer to which the variable value is copied
• • @data: buffer to which the variable value is copied
• • Return: status code

• • Return: Pointer to pkcs7_message structure on success, NULL on error
  */

-efi_status_t EFIAPI efi_get_variable(u16 *variable_name,

• 		     const efi_guid_t *vendor, u32 *attributes,
  

• 		     efi_uintn_t *data_size, void *data)
  

+static struct pkcs7_message *efi_variable_parse_signature(const void *buf,

• 					  size_t buflen)
  

+{

• u8 *ebuf;
• size_t ebuflen, len;
• struct pkcs7_message *msg;
• /*

• * This is the best assumption to check if the binary is
  

• * already in a form of pkcs7's signedData.
  

• */
  

• if (buflen > sizeof(pkcs7_hdr) &&

•    !memcmp(&((u8 *)buf)[4], &pkcs7_hdr[4], 11)) {
  

• msg = pkcs7_parse_message(buf, buflen);
  

• goto out;
  

• }
• /*

• * Otherwise, we should add a dummy prefix sequence for pkcs7
  

• * message parser to be able to process.
  

• * NOTE: EDK2 also uses similar hack in WrapPkcs7Data()
  

• * in CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7VerifyCommon.c
  

• * TODO:
  

• * The header should be composed in a more refined manner.
  

• */
  

• debug("Makeshift prefix added to authentication data\n");
• ebuflen = sizeof(pkcs7_hdr) + buflen;
• if (ebuflen <= 0x7f) {

• debug("Data is too short\n");
  

• return NULL;
  

• }
• ebuf = malloc(ebuflen);
• if (!ebuf) {

• debug("Out of memory\n");
  

• return NULL;
  

• }
• memcpy(ebuf, pkcs7_hdr, sizeof(pkcs7_hdr));
• memcpy(ebuf + sizeof(pkcs7_hdr), buf, buflen);
• len = ebuflen - 4;
• ebuf[2] = (len >> 8) & 0xff;
• ebuf[3] = len & 0xff;
• len = ebuflen - 0x13;
• ebuf[0x11] = (len >> 8) & 0xff;
• ebuf[0x12] = len & 0xff;
• msg = pkcs7_parse_message(ebuf, ebuflen);
• free(ebuf);

+out:

• if (IS_ERR(msg))

• return NULL;
  

• return msg;

+}

+/**

• • efi_variable_authenticate - authenticate a variable
• • @variable: Variable name in u16
• • @vendor: Guid of variable
• • @data_size: Size of @data
• • @data: Pointer to variable's value
• • @given_attr: Attributes to be given at SetVariable()
• • @env_attr: Attributes that an existing variable holds
• • @time: signed time that an existing variable holds
• • Called by efi_set_variable() to verify that the input is correct.
• • Will replace the given data pointer with another that points to
• • the actual data to store in the internal memory.
• • On success, @data and @data_size will be replaced with variable's
• • actual data, excluding authentication data, and its size, and variable's
• • attributes and signed time will also be returned in @env_attr and @time,
• • respectively.
• • Return: EFI_SUCCESS on success, status code (negative) on error
• */

+static efi_status_t efi_variable_authenticate(u16 *variable,

• 			      const efi_guid_t *vendor,
  

• 			      efi_uintn_t *data_size,
  

• 			      const void **data, u32 given_attr,
  

• 			      u32 *env_attr, u64 *time)
  

+{

• const struct efi_variable_authentication_2 *auth;
• struct efi_signature_store *truststore, *truststore2;
• struct pkcs7_message *var_sig;
• struct efi_image_regions *regs;
• const struct efi_time *timestamp;
• struct rtc_time tm;
• u64 new_time;
• efi_status_t ret;
• var_sig = NULL;
• truststore = NULL;
• truststore2 = NULL;
• regs = NULL;
• ret = EFI_SECURITY_VIOLATION;
• if (*data_size < sizeof(struct efi_variable_authentication_2))

• goto err;
  

• /* authentication data */
• auth = *data;
• if (*data_size < (sizeof(auth->time_stamp)

• 		+ auth->auth_info.hdr.dwLength))
  

• goto err;
  

• if (guidcmp(&auth->auth_info.cert_type, &efi_guid_cert_type_pkcs7))

• goto err;
  

• *data += sizeof(auth->time_stamp) + auth->auth_info.hdr.dwLength;
• *data_size -= (sizeof(auth->time_stamp)

• 		+ auth->auth_info.hdr.dwLength);
  

• timestamp = &auth->time_stamp;

This does not compile with GCC 9.2.1:

lib/efi_loader/efi_variable.c: In function ‘efi_variable_authenticate’: lib/efi_loader/efi_variable.c:554:14: error: taking address of packed member of ‘struct efi_variable_authentication_2’ may result in an unaligned pointer value [-Werror=address-of-packed-member] 554 | timestamp = &auth->time_stamp; | ^~~~~~~~~~~~~~~~~

Okay. The line will be replaced with memcpy.

Thanks, -Takahiro Akashi

Best regards

Heinrich

...

• memset(&tm, 0, sizeof(tm));
• tm.tm_year = timestamp->year;
• tm.tm_mon = timestamp->month;
• tm.tm_mday = timestamp->day;
• tm.tm_hour = timestamp->hour;
• tm.tm_min = timestamp->minute;
• tm.tm_sec = timestamp->second;
• new_time = rtc_mktime(&tm);
• if (!efi_secure_boot_enabled()) {

• /* finished checking */
  

• *time = new_time;
  

• return EFI_SUCCESS;
  

• }
• if (new_time <= *time)

• goto err;
  

• /* data to be digested */
• regs = calloc(sizeof(*regs) + sizeof(struct image_region) * 5, 1);
• if (!regs)

• goto err;
  

• regs->max = 5;
• efi_image_region_add(regs, (uint8_t *)variable,

• 	     (uint8_t *)variable
  

• 		+ u16_strlen(variable) * sizeof(u16), 1);
  

• efi_image_region_add(regs, (uint8_t *)vendor,

• 	     (uint8_t *)vendor + sizeof(*vendor), 1);
  

• efi_image_region_add(regs, (uint8_t *)&given_attr,

• 	     (uint8_t *)&given_attr + sizeof(given_attr), 1);
  

• efi_image_region_add(regs, (uint8_t *)timestamp,

• 	     (uint8_t *)timestamp + sizeof(*timestamp), 1);
  

• efi_image_region_add(regs, (uint8_t *)*data,

• 	     (uint8_t *)*data + *data_size, 1);
  

• /* variable's signature list */
• if (auth->auth_info.hdr.dwLength < sizeof(auth->auth_info))

• goto err;
  

• var_sig = efi_variable_parse_signature(auth->auth_info.cert_data,

• 			       auth->auth_info.hdr.dwLength
  

• 				   - sizeof(auth->auth_info));
  

• if (IS_ERR(var_sig)) {

• debug("Parsing variable's signature failed\n");
  

• var_sig = NULL;
  

• goto err;
  

• }
• /* signature database used for authentication */
• if (u16_strcmp(variable, L"PK") == 0 ||

•    u16_strcmp(variable, L"KEK") == 0) {
  

• /* with PK */
  

• truststore = efi_sigstore_parse_sigdb(L"PK");
  

• if (!truststore)
  

• 	goto err;
  

• } else if (u16_strcmp(variable, L"db") == 0 ||

•    u16_strcmp(variable, L"dbx") == 0) {
  

• /* with PK and KEK */
  

• truststore = efi_sigstore_parse_sigdb(L"KEK");
  

• truststore2 = efi_sigstore_parse_sigdb(L"PK");
  

• if (!truststore) {
  

• 	if (!truststore2)
  

• 		goto err;
  

• 	truststore = truststore2;
  

• 	truststore2 = NULL;
  

• }
  

• } else {

• /* TODO: support private authenticated variables */
  

• goto err;
  

• }
• /* verify signature */
• if (efi_signature_verify_with_sigdb(regs, var_sig, truststore, NULL)) {

• debug("Verified\n");
  

• } else {

• if (truststore2 &&
  

•     efi_signature_verify_with_sigdb(regs, var_sig,
  

• 				    truststore2, NULL)) {
  

• 	debug("Verified\n");
  

• } else {
  

• 	debug("Verifying variable's signature failed\n");
  

• 	goto err;
  

• }
  

• }
• /* finished checking */
• *time = rtc_mktime(&tm);
• ret = EFI_SUCCESS;

+err:

• efi_sigstore_free(truststore);
• efi_sigstore_free(truststore2);
• pkcs7_free_message(var_sig);
• free(regs);
• return ret;

+} +#else +static efi_status_t efi_variable_authenticate(u16 *variable,

• 			      const efi_guid_t *vendor,
  

• 			      efi_uintn_t *data_size,
  

• 			      const void **data, u32 given_attr,
  

• 			      u32 *env_attr, u64 *time)
  

+{

• return EFI_SUCCESS;

+} +#endif /* CONFIG_EFI_SECURE_BOOT */

+static +efi_status_t EFIAPI efi_get_variable_common(u16 *variable_name,

• 			    const efi_guid_t *vendor,
  

• 			    u32 *attributes,
  

• 			    efi_uintn_t *data_size, void *data,
  

• 			    bool is_non_volatile)
  

{ char *native_name; efi_status_t ret; unsigned long in_size;

• const char *val, *s;

• const char *val = NULL, *s;
• u64 time = 0; u32 attr;

• EFI_ENTRY(""%ls" %pUl %p %p %p", variable_name, vendor, attributes,

•   data_size, data);
  

• if (!variable_name || !vendor || !data_size) return EFI_EXIT(EFI_INVALID_PARAMETER);

  ret = efi_to_native(&native_name, variable_name, vendor); if (ret)

• return EFI_EXIT(ret);
  

• return ret;
  
  

  EFI_PRINT("get '%s'\n", native_name);

  val = env_get(native_name); free(native_name); if (!val)

• return EFI_EXIT(EFI_NOT_FOUND);
  

• return EFI_NOT_FOUND;
  
  

• val = parse_attr(val, &attr);

• val = parse_attr(val, &attr, &time);

  in_size = *data_size;

@@ -197,7 +452,7 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name,

/* number of hexadecimal digits must be even */
if (len & 1)

• 	return EFI_EXIT(EFI_DEVICE_ERROR);
  

• 	return EFI_DEVICE_ERROR;
  
  

  /* two characters per byte: */ len /= 2;

@@ -208,11 +463,13 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name, goto out; }

• if (!data)
  

• 	return EFI_EXIT(EFI_INVALID_PARAMETER);
  

• if (!data) {
  

• 	debug("Variable with no data shouldn't exist.\n");
  

• 	return EFI_INVALID_PARAMETER;
  

• }
  
  

  if (hex2bin(data, s, len))

• 	return EFI_EXIT(EFI_DEVICE_ERROR);
  

• 	return EFI_DEVICE_ERROR;
  
  

  EFI_PRINT("got value: "%s"\n", s); } else if ((s = prefix(val, "(utf8)"))) {

@@ -225,8 +482,10 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name, goto out; }

• if (!data)
  

• 	return EFI_EXIT(EFI_INVALID_PARAMETER);
  

• if (!data) {
  

• 	debug("Variable with no data shouldn't exist.\n");
  

• 	return EFI_INVALID_PARAMETER;
  

• }
  
  

  memcpy(data, s, len); ((char *)data)[len] = '\0';

@@ -234,13 +493,67 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name, EFI_PRINT("got value: "%s"\n", (char *)data); } else { EFI_PRINT("invalid value: '%s'\n", val);

• return EFI_EXIT(EFI_DEVICE_ERROR);
  

• return EFI_DEVICE_ERROR;
  

  }

out: if (attributes) *attributes = attr & EFI_VARIABLE_MASK;

• return ret;

+}

+static +efi_status_t EFIAPI efi_get_volatile_variable(u16 *variable_name,

• 			      const efi_guid_t *vendor,
  

• 			      u32 *attributes,
  

• 			      efi_uintn_t *data_size,
  

• 			      void *data)
  

+{

• return efi_get_variable_common(variable_name, vendor, attributes,

• 		       data_size, data, false);
  

+}

+efi_status_t EFIAPI efi_get_nonvolatile_variable(u16 *variable_name,

• 				 const efi_guid_t *vendor,
  

• 				 u32 *attributes,
  

• 				 efi_uintn_t *data_size,
  

• 				 void *data)
  

+{

• return efi_get_variable_common(variable_name, vendor, attributes,

• 		       data_size, data, true);
  

+}

+/**

• • efi_efi_get_variable() - retrieve value of a UEFI variable
• • This function implements the GetVariable runtime service.
• • See the Unified Extensible Firmware Interface (UEFI) specification for
• • details.
• • @variable_name: name of the variable
• • @vendor: vendor GUID
• • @attributes: attributes of the variable
• • @data_size: size of the buffer to which the variable value is copied
• • @data: buffer to which the variable value is copied
• • Return: status code
• */

+efi_status_t EFIAPI efi_get_variable(u16 *variable_name,

• 		     const efi_guid_t *vendor, u32 *attributes,
  

• 		     efi_uintn_t *data_size, void *data)
  

+{

• efi_status_t ret;
• EFI_ENTRY(""%ls" %pUl %p %p %p", variable_name, vendor, attributes,

•   data_size, data);
  

• ret = efi_get_volatile_variable(variable_name, vendor, attributes,

• 			data_size, data);
  

• if (ret == EFI_NOT_FOUND)

• ret = efi_get_nonvolatile_variable(variable_name, vendor,
  

• 				   attributes, data_size, data);
  

• return EFI_EXIT(ret);

}

@@ -273,6 +586,7 @@ static efi_status_t parse_uboot_variable(char *variable, { char *guid, *name, *end, c; unsigned long name_len;

• u64 time; u16 *p;

  guid = strchr(variable, '_');

@@ -307,7 +621,7 @@ static efi_status_t parse_uboot_variable(char *variable, *(name - 1) = c;

/* attributes */

• parse_attr(end, attributes);

• parse_attr(end, attributes, &time);

  return EFI_SUCCESS;

} @@ -389,7 +703,7 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size, list_len = hexport_r(&env_htab, '\n', H_MATCH_REGEX | H_MATCH_KEY, &efi_variables_list, 0, 1, regexlist);

• /* 1 indicates that no match was found */
  

• if (list_len <= 1) return EFI_EXIT(EFI_NOT_FOUND);

@@ -402,143 +716,286 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size, return EFI_EXIT(ret); }

-/**

• • efi_set_variable() - set value of a UEFI variable
• • This function implements the SetVariable runtime service.
• • See the Unified Extensible Firmware Interface (UEFI) specification for
• • details.
• • @variable_name: name of the variable
• • @vendor: vendor GUID
• • @attributes: attributes of the variable
• • @data_size: size of the buffer with the variable value
• • @data: buffer with the variable value
• • Return: status code
• */

-efi_status_t EFIAPI efi_set_variable(u16 *variable_name,

• 		     const efi_guid_t *vendor, u32 attributes,
  

• 		     efi_uintn_t data_size, const void *data)
  

+static +efi_status_t EFIAPI efi_set_variable_common(u16 *variable_name,

• 			    const efi_guid_t *vendor,
  

• 			    u32 attributes,
  

• 			    efi_uintn_t data_size,
  

• 			    const void *data,
  

• 			    bool ro_check,
  

• 			    bool is_non_volatile)
  

{

• char *native_name = NULL, *val = NULL, *s;
• const char *old_val;
• size_t old_size;
• efi_status_t ret = EFI_SUCCESS;

• char *native_name = NULL, *old_data = NULL, *val = NULL, *s;
• efi_uintn_t old_size;
• bool append, delete;
• u64 time = 0; u32 attr;
• efi_status_t ret = EFI_SUCCESS;

• EFI_ENTRY(""%ls" %pUl %x %zu %p", variable_name, vendor, attributes,

•   data_size, data);
  

• debug("%s: set '%s'\n", __func__, native_name);

  if (!variable_name || !*variable_name || !vendor || ((attributes & EFI_VARIABLE_RUNTIME_ACCESS) && !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS))) { ret = EFI_INVALID_PARAMETER;

• goto out;
  

• goto err;
  

  }

  ret = efi_to_native(&native_name, variable_name, vendor); if (ret)

• goto out;
  

• goto err;
  

• /* check if a variable exists */
• old_size = 0;
• attr = 0;
• ret = EFI_CALL(efi_get_variable(variable_name, vendor, &attr,

• 			&old_size, NULL));
  

• if (ret == EFI_BUFFER_TOO_SMALL) {

• if ((is_non_volatile && !(attr & EFI_VARIABLE_NON_VOLATILE)) ||
  

•     (!is_non_volatile && (attr & EFI_VARIABLE_NON_VOLATILE))) {
  

• 	ret = EFI_INVALID_PARAMETER;
  

• 	goto err;
  

• }
  

• }

• old_val = env_get(native_name);
• if (old_val) {

• old_val = parse_attr(old_val, &attr);
  

• append = !!(attributes & EFI_VARIABLE_APPEND_WRITE);
• attributes &= ~(u32)EFI_VARIABLE_APPEND_WRITE;
• delete = !append && (!data_size || !attributes);

• /* check read-only first */
  

• if (attr & READ_ONLY) {
  

• /* check attributes */
• if (old_size) {

• if (ro_check && (attr & READ_ONLY)) {
  ret = EFI_WRITE_PROTECTED;
  

• 	goto out;
  

• }
  

• if ((data_size == 0 &&
  

•      !(attributes & EFI_VARIABLE_APPEND_WRITE)) ||
  

•     !attributes) {
  

• 	/* delete the variable: */
  

• 	env_set(native_name, NULL);
  

• 	ret = EFI_SUCCESS;
  

• 	goto out;
  

• 	goto err;
  

  }

  /* attributes won't be changed */

• if (attr != (attributes & ~EFI_VARIABLE_APPEND_WRITE)) {
  

• if (!delete &&
  

•     ((ro_check && attr != attributes) ||
  

•      (!ro_check && ((attr & ~(u32)READ_ONLY)
  

• 		    != (attributes & ~(u32)READ_ONLY))))) {
  ret = EFI_INVALID_PARAMETER;
  

• 	goto out;
  

• }
  

• if (attributes & EFI_VARIABLE_APPEND_WRITE) {
  

• 	if (!prefix(old_val, "(blob)")) {
  

• 		ret = EFI_DEVICE_ERROR;
  

• 		goto out;
  

• 	}
  

• 	old_size = strlen(old_val);
  

• } else {
  

• 	old_size = 0;
  

• 	goto err;
  

  } } else {

• if (data_size == 0 || !attributes ||
  

•     (attributes & EFI_VARIABLE_APPEND_WRITE)) {
  

• if (delete || append) {
  /*
   * Trying to delete or to update a non-existent
   * variable.
   */
  ret = EFI_NOT_FOUND;
  

• 	goto out;
  

• 	goto err;
  

• }
  

• }

• if (((!u16_strcmp(variable_name, L"PK") ||

•      !u16_strcmp(variable_name, L"KEK")) &&
  

• !guidcmp(vendor, &efi_global_variable_guid)) ||
  

•    ((!u16_strcmp(variable_name, L"db") ||
  

•      !u16_strcmp(variable_name, L"dbx")) &&
  

• !guidcmp(vendor, &efi_guid_image_security_database))) {
  

• /* authentication is mandatory */
  

• if (!(attributes &
  

•       EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
  

• 	debug("%ls: AUTHENTICATED_WRITE_ACCESS required\n",
  

• 	      variable_name);
  

• 	ret = EFI_INVALID_PARAMETER;
  

• 	goto err;
  

  }

• }

• /* authenticate a variable */

• if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) {

• if (attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) {
  

• 	ret = EFI_INVALID_PARAMETER;
  

• 	goto err;
  

• }
  

• if (attributes &
  

•     EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
  

• 	ret = efi_variable_authenticate(variable_name, vendor,
  

• 					&data_size, &data,
  

• 					attributes, &attr,
  

• 					&time);
  

• 	if (ret != EFI_SUCCESS)
  

• 		goto err;
  

• 	/* last chance to check for delete */
  

• 	if (!data_size)
  

• 		delete = true;
  

• }
  

• } else {

• if (attributes &
  

•     (EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
  

•      EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
  

• 	debug("Secure boot is not configured\n");
  

• 	ret = EFI_INVALID_PARAMETER;
  

• 	goto err;
  

• }
  

• }

• /* delete a variable */

• if (delete) {

• /* !old_size case has been handled before */
  

• val = NULL;
  

• ret = EFI_SUCCESS;
  

• goto out;
  

• }

• if (append) {

• old_data = malloc(old_size);
  

• if (!old_data) {
  

• 	return EFI_OUT_OF_RESOURCES;
  

• 	goto err;
  

• }
  

• ret = EFI_CALL(efi_get_variable(variable_name, vendor,
  

• 				&attr, &old_size, old_data));
  

• if (ret != EFI_SUCCESS)
  

• 	goto err;
  

• } else { old_size = 0; }

• val = malloc(old_size + 2 * data_size

•      + strlen("{ro,run,boot,nv}(blob)") + 1);
  

• val = malloc(2 * old_size + 2 * data_size

•      + strlen("{ro,run,boot,nv,time=0123456701234567}(blob)")
  

•      + 1);
  

  if (!val) { ret = EFI_OUT_OF_RESOURCES;

• goto out;
  

• goto err;
  

  }

  s = val;

• /* store attributes */
• attributes &= (EFI_VARIABLE_NON_VOLATILE |

• /*

• * store attributes
  

• */
  

• attributes &= (READ_ONLY |

•        EFI_VARIABLE_NON_VOLATILE |
    EFI_VARIABLE_BOOTSERVICE_ACCESS |
  

•        EFI_VARIABLE_RUNTIME_ACCESS);
  

•        EFI_VARIABLE_RUNTIME_ACCESS |
  

•        EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS);
  

  s += sprintf(s, "{"); while (attributes) {

• u32 attr = 1 << (ffs(attributes) - 1);
  

• attr = 1 << (ffs(attributes) - 1);
  
  

• if (attr == EFI_VARIABLE_NON_VOLATILE)
  

• if (attr == READ_ONLY) {
  

• 	s += sprintf(s, "ro");
  

• } else if (attr == EFI_VARIABLE_NON_VOLATILE) {
  s += sprintf(s, "nv");
  

• else if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS)
  

• } else if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS) {
  s += sprintf(s, "boot");
  

• else if (attr == EFI_VARIABLE_RUNTIME_ACCESS)
  

• } else if (attr == EFI_VARIABLE_RUNTIME_ACCESS) {
  s += sprintf(s, "run");
  

• } else if (attr ==
  

• 	   EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
  

• 	s += sprintf(s, "time=");
  

• 	s = bin2hex(s, (u8 *)&time, sizeof(time));
  

• }
  
  

  attributes &= ~attr; if (attributes) s += sprintf(s, ","); } s += sprintf(s, "}");

• if (old_size)

• /* APPEND_WRITE */
  

• s += sprintf(s, old_val);
  

• else

• s += sprintf(s, "(blob)");
  

• s += sprintf(s, "(blob)");

  /* store payload: */

• if (append)

• s = bin2hex(s, old_data, old_size);
  

  s = bin2hex(s, data, data_size); *s = '\0';

  EFI_PRINT("setting: %s=%s\n", native_name, val);

+out: if (env_set(native_name, val)) ret = EFI_DEVICE_ERROR;

• else

• ret = EFI_SUCCESS;
  
  

-out: +err: free(native_name);

• free(old_data); free(val);

• return EFI_EXIT(ret);

• return ret;

+}

+static +efi_status_t EFIAPI efi_set_volatile_variable(u16 *variable_name,

• 			      const efi_guid_t *vendor,
  

• 			      u32 attributes,
  

• 			      efi_uintn_t data_size,
  

• 			      const void *data,
  

• 			      bool ro_check)
  

+{

• return efi_set_variable_common(variable_name, vendor, attributes,

• 		       data_size, data, ro_check, false);
  

+}

+efi_status_t EFIAPI efi_set_nonvolatile_variable(u16 *variable_name,

• 				 const efi_guid_t *vendor,
  

• 				 u32 attributes,
  

• 				 efi_uintn_t data_size,
  

• 				 const void *data,
  

• 				 bool ro_check)
  

+{

• efi_status_t ret;
• ret = efi_set_variable_common(variable_name, vendor, attributes,

• 		      data_size, data, ro_check, true);
  

• return ret;

+}

+static efi_status_t efi_set_variable_internal(u16 *variable_name,

• 			      const efi_guid_t *vendor,
  

• 			      u32 attributes,
  

• 			      efi_uintn_t data_size,
  

• 			      const void *data,
  

• 			      bool ro_check)
  

+{

• efi_status_t ret;
• if (attributes & EFI_VARIABLE_NON_VOLATILE)

• ret = efi_set_nonvolatile_variable(variable_name, vendor,
  

• 				   attributes,
  

• 				   data_size, data, ro_check);
  

• else

• ret = efi_set_volatile_variable(variable_name, vendor,
  

• 				attributes, data_size, data,
  

• 				ro_check);
  

• return ret;

+}

+/**

• • efi_set_variable() - set value of a UEFI variable
• • This function implements the SetVariable runtime service.
• • See the Unified Extensible Firmware Interface (UEFI) specification for
• • details.
• • @variable_name: name of the variable
• • @vendor: vendor GUID
• • @attributes: attributes of the variable
• • @data_size: size of the buffer with the variable value
• • @data: buffer with the variable value
• • Return: status code
• */

+efi_status_t EFIAPI efi_set_variable(u16 *variable_name,

• 		     const efi_guid_t *vendor, u32 attributes,
  

• 		     efi_uintn_t data_size, const void *data)
  

+{

• EFI_ENTRY(""%ls" %pUl %x %zu %p", variable_name, vendor, attributes,

•   data_size, data);
  

• /* READ_ONLY bit is not part of API */
• attributes &= ~(u32)READ_ONLY;
• return EFI_EXIT(efi_set_variable_internal(variable_name, vendor,

• 				  attributes, data_size, data,
  

• 				  true));
  

}

/**

On 12/18/19 1:45 AM, AKASHI Takahiro wrote:

With this commit, image validation can be enforced, as UEFI specification section 32.5 describes, if CONFIG_EFI_SECURE_BOOT is enabled.

Currently we support

• authentication based on db and dbx, so dbx-validated image will always be rejected.
• following signature types: EFI_CERT_SHA256_GUID (SHA256 digest for unsigned images) EFI_CERT_X509_GUID (x509 certificate for signed images)

Timestamp-based certificate revocation is not supported here.

Internally, authentication data is stored in one of certificates tables of PE image (See efi_image_parse()) and will be verified by efi_image_authenticate() before loading a given image.

It seems that UEFI specification defines the verification process in a bit ambiguous way. I tried to implement it as closely to as EDK2 does.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org

include/efi_loader.h | 7 +- lib/efi_loader/efi_boottime.c | 2 +- lib/efi_loader/efi_image_loader.c | 454 +++++++++++++++++++++++++++++- 3 files changed, 449 insertions(+), 14 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h index 1f88caf86709..e12b49098fb0 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -11,6 +11,7 @@ #include <common.h> #include <part_efi.h> #include <efi_api.h> +#include <pe.h>

static inline int guidcmp(const void *g1, const void *g2) { @@ -398,7 +399,8 @@ efi_status_t efi_set_watchdog(unsigned long timeout); /* Called from places to check whether a timer expired */ void efi_timer_check(void); /* PE loader implementation */ -efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, +efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,

• 	 void *efi, size_t efi_size,
   struct efi_loaded_image *loaded_image_info);
  

  /* Called once to store the pristine gd pointer */ void efi_save_gd(void);

@@ -726,6 +728,9 @@ void efi_sigstore_free(struct efi_signature_store *sigstore); struct efi_signature_store *efi_sigstore_parse_sigdb(u16 *name);

bool efi_secure_boot_enabled(void);

+bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,

•      WIN_CERTIFICATE **auth, size_t *auth_len);
  

  #endif /* CONFIG_EFI_SECURE_BOOT */

  #else /* CONFIG_IS_ENABLED(EFI_LOADER) */

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c index 493d906c641d..311681764034 100644 --- a/lib/efi_loader/efi_boottime.c +++ b/lib/efi_loader/efi_boottime.c @@ -1879,7 +1879,7 @@ efi_status_t EFIAPI efi_load_image(bool boot_policy, efi_dp_split_file_path(file_path, &dp, &fp); ret = efi_setup_loaded_image(dp, fp, image_obj, &info); if (ret == EFI_SUCCESS)

• ret = efi_load_pe(*image_obj, dest_buffer, info);
  

• ret = efi_load_pe(*image_obj, dest_buffer, source_size, info);
  

  if (!source_buffer) /* Release buffer to which file was loaded */ efi_free_pages((uintptr_t)dest_buffer,

diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c index 13541cfa7a28..939758e61e3c 100644 --- a/lib/efi_loader/efi_image_loader.c +++ b/lib/efi_loader/efi_image_loader.c @@ -9,7 +9,9 @@

#include <common.h> #include <efi_loader.h> +#include <malloc.h> #include <pe.h> +#include "../lib/crypto/pkcs7_parser.h"

const efi_guid_t efi_global_variable_guid = EFI_GLOBAL_VARIABLE_GUID; const efi_guid_t efi_guid_device_path = EFI_DEVICE_PATH_PROTOCOL_GUID; @@ -205,6 +207,367 @@ static void efi_set_code_and_data_type( } }

+#ifdef CONFIG_EFI_SECURE_BOOT +/**

• • efi_image_parse - parse a PE image
• • @efi: Pointer to image
• • @len: Size of @efi
• • @regs: Pointer to a list of regions
• • @auth: Pointer to a pointer to authentication data in PE
• • @auth_len: Size of @auth
• • Parse image binary in PE32(+) format, assuming that sanity of PE image
• • has been checked by a caller.
• • On success, an address of authentication data in @efi and its size will
• • be returned in @auth and @auth_len, respectively.
• • Return: true on success, false on error
• */

+bool efi_image_parse(void *efi, size_t len, struct efi_image_regions **regp,

•      WIN_CERTIFICATE **auth, size_t *auth_len)
  

This function is way too long (> 100 lines). Please, cut it into logical units.

+{

• struct efi_image_regions *regs;
• IMAGE_DOS_HEADER *dos;
• IMAGE_NT_HEADERS32 *nt;
• IMAGE_SECTION_HEADER *sections, **sorted;
• int num_regions, num_sections, i, j;
• int ctidx = IMAGE_DIRECTORY_ENTRY_SECURITY;
• u32 align, size, authsz, authoff;
• size_t bytes_hashed;
• dos = (void *)efi;
• nt = (void *)(efi + dos->e_lfanew);
• /*

• * Count maximum number of regions to be digested.
  

• * We don't have to have an exact number here.
  

• * See efi_image_region_add()'s in parsing below.
  

• */
  

• num_regions = 3; /* for header */
• num_regions += nt->FileHeader.NumberOfSections;
• num_regions++; /* for extra */
• regs = calloc(sizeof(*regs) + sizeof(struct image_region) * num_regions,

•       1);
  

• if (!regs)

• goto err;
  

• regs->max = num_regions;
• /*

• * Collect data regions for hash calculation
  

• * 1. File headers
  

• */
  

• if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {

• IMAGE_NT_HEADERS64 *nt64 = (void *)nt;
  

• IMAGE_OPTIONAL_HEADER64 *opt = &nt64->OptionalHeader;
  

• /* Skip CheckSum */
  

• efi_image_region_add(regs, efi, &opt->CheckSum, 0);
  

• if (nt64->OptionalHeader.NumberOfRvaAndSizes <= ctidx) {
  

• 	efi_image_region_add(regs,
  

• 			     &opt->CheckSum + 1,
  

• 			     efi + opt->SizeOfHeaders, 0);
  

• } else {
  

• 	/* Skip Certificates Table */
  

• 	efi_image_region_add(regs,
  

• 			     &opt->CheckSum + 1,
  

• 			     &opt->DataDirectory[ctidx], 0);
  

• 	efi_image_region_add(regs,
  

• 			     &opt->DataDirectory[ctidx] + 1,
  

• 			     efi + opt->SizeOfHeaders, 0);
  

• }
  

• bytes_hashed = opt->SizeOfHeaders;
  

• align = opt->FileAlignment;
  

• authoff = opt->DataDirectory[ctidx].VirtualAddress;
  

• authsz = opt->DataDirectory[ctidx].Size;
  

• } else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {

• IMAGE_OPTIONAL_HEADER32 *opt = &nt->OptionalHeader;
  

• efi_image_region_add(regs, efi, &opt->CheckSum, 0);
  

• efi_image_region_add(regs, &opt->CheckSum + 1,
  

• 		     &opt->DataDirectory[ctidx], 0);
  

• efi_image_region_add(regs, &opt->DataDirectory[ctidx] + 1,
  

• 		     efi + opt->SizeOfHeaders, 0);
  

• bytes_hashed = opt->SizeOfHeaders;
  

• align = opt->FileAlignment;
  

• authoff = opt->DataDirectory[ctidx].VirtualAddress;
  

• authsz = opt->DataDirectory[ctidx].Size;
  

• } else {

• debug("%s: Invalid optional header magic %x\n", __func__,
  

•       nt->OptionalHeader.Magic);
  

• goto err;
  

• }
• /* 2. Sections */
• num_sections = nt->FileHeader.NumberOfSections;
• sections = (void *)((uint8_t *)&nt->OptionalHeader +

• 	    nt->FileHeader.SizeOfOptionalHeader);
  

• sorted = calloc(sizeof(IMAGE_SECTION_HEADER *), num_sections);
• if (!sorted) {

• debug("%s: Out of memory\n", __func__);
  

• goto err;
  

• }
• /*

• * Make sure the section list is in ascending order.
  

• * As we can assume that it is already ordered in most cases,
  

• * the following code is optimized for this.
  

• */
  

• for (sorted[0] = &sections[0], i = 1; i < num_sections; i++) {

If sections[0] is not the lowest entry this function fails.

Please, use qsort() supplied in lib/qsort.c.

• if (sorted[i - 1]->VirtualAddress
  

• 		<= sections[i].VirtualAddress) {
  

• 	sorted[i] = &sections[i];
  

• } else {
  

• 	if (i == 1) {
  

• 		sorted[1] = sorted[0];
  

• 		sorted[0] = &sections[1];
  

• 		continue;
  

• 	}
  

• 	sorted[i] = sorted[i - 1];
  

• 	for (j = i - 2; j >= 0; j--) {
  

• 		if (!j || sorted[j]->VirtualAddress
  

• 				<= sections[i].VirtualAddress) {
  

• 			sorted[j + 1] = &sections[i];
  

• 			continue;
  

• 		} else {
  

• 			sorted[j + 1] = sorted[j];
  

• 		}
  

• 	}
  

• }
  

• }
• for (i = 0; i < num_sections; i++) {

• if (!sorted[i]->SizeOfRawData)
  

• 	continue;
  

• size = (sorted[i]->SizeOfRawData + align - 1) & ~(align - 1);
  

• efi_image_region_add(regs, efi + sorted[i]->PointerToRawData,
  

• 		     efi + sorted[i]->PointerToRawData + size,
  

• 		     0);
  

• debug("section[%d](%s): raw: 0x%x-0x%x, virt: %x-%x\n",
  

•       i, sorted[i]->Name,
  

•       sorted[i]->PointerToRawData,
  

•       sorted[i]->PointerToRawData + size,
  

•       sorted[i]->VirtualAddress,
  

•       sorted[i]->VirtualAddress
  

• 	+ sorted[i]->Misc.VirtualSize);
  

• bytes_hashed += size;
  

• }
• free(sorted);
• /* 3. Extra data excluding Certificates Table */
• if (bytes_hashed + authsz < len) {

• debug("extra data for hash: %lu\n",
  

•       len - (bytes_hashed + authsz));
  

• efi_image_region_add(regs, efi + bytes_hashed,
  

• 		     efi + len - authsz, 0);
  

• }
• /* Return Certificates Table */
• if (authsz) {

• if (len < authoff + authsz) {
  

• 	debug("%s: Size for auth too large: %u >= %zu\n",
  

• 	      __func__, authsz, len - authoff);
  

• 	goto err;
  

• }
  

• if (authsz < sizeof(*auth)) {
  

• 	debug("%s: Size for auth too small: %u < %zu\n",
  

• 	      __func__, authsz, sizeof(*auth));
  

• 	goto err;
  

• }
  

• *auth = efi + authoff;
  

• *auth_len = authsz;
  

• debug("WIN_CERTIFICATE: 0x%x, size: 0x%x\n", authoff, authsz);
  

• } else {

• *auth = NULL;
  

• *auth_len = 0;
  

• }
• *regp = regs;
• return true;

+err:

• free(regs);
• return false;

+}

+/**

• • efi_image_unsigned_authenticate - authenticate unsigned image with
• • SHA256 hash
• • @regs: List of regions to be verified
• • If an image is not signed, it doesn't have a signature. In this case,
• • its message digest is calculated and it will be compared with one of
• • hash values stored in signature databases.
• • Return: true if authenticated, false if not
• */

+static bool efi_image_unsigned_authenticate(struct efi_image_regions *regs) +{

• struct efi_signature_store *db = NULL, *dbx = NULL;
• bool ret = false;
• dbx = efi_sigstore_parse_sigdb(L"dbx");
• if (!dbx) {

• debug("Getting signature database(dbx) failed\n");
  

• goto out;
  

• }
• db = efi_sigstore_parse_sigdb(L"db");
• if (!db) {

• debug("Getting signature database(db) failed\n");
  

• goto out;
  

• }
• /* try black-list first */
• if (efi_signature_verify_with_sigdb(regs, NULL, dbx, NULL)) {

• debug("Image is not signed and rejected by \"dbx\"\n");
  

• goto out;
  

• }
• /* try white-list */
• if (efi_signature_verify_with_sigdb(regs, NULL, db, NULL))

• ret = true;
  

• else

• debug("Image is not signed and not found in \"db\" or \"dbx\"\n");
  

+out:

• efi_sigstore_free(db);
• efi_sigstore_free(dbx);
• return ret;

+}

+/**

• • efi_image_authenticate - verify a signature of signed image
• • @efi: Pointer to image
• • @len: Size of @efi
• • A signed image should have its signature stored in a table of its PE header.
• • So if an image is signed and only if if its signature is verified using
• • signature databases, an image is authenticated.
• • If an image is not signed, its validity is checked by using
• • efi_image_unsigned_authenticated().
• • TODO:
• • When AuditMode==0, if the image's signature is not found in
• • the authorized database, or is found in the forbidden database,
• • the image will not be started and instead, information about it
• • will be placed in this table.
• • When AuditMode==1, an EFI_IMAGE_EXECUTION_INFO element is created
• • in the EFI_IMAGE_EXECUTION_INFO_TABLE for every certificate found
• • in the certificate table of every image that is validated.
• • Return: true if authenticated, false if not
• */

+static bool efi_image_authenticate(void *efi, size_t len) +{

• struct efi_image_regions *regs = NULL;
• WIN_CERTIFICATE *wincerts = NULL, *wincert;
• size_t wincerts_len;
• struct pkcs7_message *msg = NULL;
• struct efi_signature_store *db = NULL, *dbx = NULL;
• struct x509_certificate *cert = NULL;
• bool ret = false;
• if (!efi_secure_boot_enabled())

• return true;
  

• if (!efi_image_parse(efi, len, &regs, &wincerts,

• 	     &wincerts_len)) {
  

• debug("Parsing PE executable image failed\n");
  

• return false;
  

• }
• if (!wincerts) {

• /* The image is not signed */
  

• ret = efi_image_unsigned_authenticate(regs);
  

• free(regs);
  

• return ret;
  

• }
• /*

• * verify signature using db and dbx
  

• */
  

• db = efi_sigstore_parse_sigdb(L"db");
• if (!db) {

• debug("Getting signature database(db) failed\n");
  

• goto err;
  

• }
• dbx = efi_sigstore_parse_sigdb(L"dbx");
• if (!dbx) {

• debug("Getting signature database(dbx) failed\n");
  

• goto err;
  

• }
• /* go through WIN_CERTIFICATE list */
• for (wincert = wincerts;

•     (void *)wincert < (void *)wincerts + wincerts_len;
  

•     wincert = (void *)wincert + ALIGN(wincert->dwLength, 8)) {
  

• if (wincert->dwLength < sizeof(*wincert)) {
  

• 	debug("%s: dwLength too small: %u < %zu\n",
  

• 	      __func__, wincert->dwLength, sizeof(*wincert));
  

• 	goto err;
  

• }
  

• msg = pkcs7_parse_message((void *)wincert + sizeof(*wincert),
  

• 			  wincert->dwLength - sizeof(*wincert));
  

• if (!msg) {
  

• 	debug("Parsing image's signature failed\n");
  

• 	goto err;
  

• }
  

• /* try black-list first */
  

• if (efi_signature_verify_with_sigdb(regs, msg, dbx, NULL)) {
  

• 	debug("Signature was rejected by \"dbx\"\n");
  

• 	goto err;
  

• }
  

• if (!efi_signature_verify_signers(msg, dbx)) {
  

• 	debug("Signer was rejected by \"dbx\"\n");
  

• 	goto err;
  

• } else {
  

• 	ret = true;
  

• }
  

• /* try white-list */
  

• if (!efi_signature_verify_with_sigdb(regs, msg, db, &cert)) {
  

• 	debug("Verifying signature with \"db\" failed\n");
  

• 	goto err;
  

• } else {
  

• 	ret = true;
  

• }
  

• if (!efi_signature_verify_cert(cert, dbx)) {
  

• 	debug("Certificate was rejected by \"dbx\"\n");
  

• 	goto err;
  

• } else {
  

• 	ret = true;
  

• }
  

• }

+err:

• x509_free_certificate(cert);
• efi_sigstore_free(db);
• efi_sigstore_free(dbx);
• pkcs7_free_message(msg);
• free(regs);
• return ret;

+} +#else +static bool efi_image_authenticate(void *efi, size_t len) +{

• return true;

+} +#endif /* CONFIG_EFI_SECURE_BOOT */

• /**
  • efi_load_pe() - relocate EFI binary

@@ -216,7 +579,8 @@ static void efi_set_code_and_data_type(

• @loaded_image_info: loaded image protocol
• Return: status code

*/ -efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, +efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,

• 	 void *efi, size_t efi_size,
   struct efi_loaded_image *loaded_image_info)
  

  { IMAGE_NT_HEADERS32 *nt;

@@ -231,17 +595,57 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, uint64_t image_base; unsigned long virt_size = 0; int supported = 0;

• void *new_efi = NULL;

• size_t new_efi_size;

• efi_status_t ret;

• /*

• * Size must be 8-byte aligned and the trailing bytes must be
  

• * zero'ed. Otherwise hash value may be incorrect.
  

• */
  

• if (efi_size & 0x7) {

• new_efi_size = (efi_size + 0x7) & ~0x7ULL;
  

• new_efi = calloc(new_efi_size, 1);
  

• if (!new_efi)
  

• 	return EFI_OUT_OF_RESOURCES;
  

• memcpy(new_efi, efi, efi_size);
  

• efi = new_efi;
  

• efi_size = new_efi_size;
  

• }

• /* Sanity check for a file header */

• if (efi_size < sizeof(*dos)) {

• printf("%s: Truncated DOS Header\n", __func__);
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

• }

  dos = efi; if (dos->e_magic != IMAGE_DOS_SIGNATURE) { printf("%s: Invalid DOS Signature\n", __func__);

• return EFI_LOAD_ERROR;
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

• }

• /* assume sizeof(IMAGE_NT_HEADERS32) <= sizeof(IMAGE_NT_HEADERS64) */

• if (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS32)) {

• printf("%s: Invalid offset for Extended Header\n", __func__);
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

  }

  nt = (void *) ((char *)efi + dos->e_lfanew);

• if ((nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) &&

•    (efi_size < dos->e_lfanew + sizeof(IMAGE_NT_HEADERS64))) {
  

• printf("%s: Invalid offset for Extended Header\n", __func__);
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

• }

• if (nt->Signature != IMAGE_NT_SIGNATURE) { printf("%s: Invalid NT Signature\n", __func__);

• return EFI_LOAD_ERROR;
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

  }

  for (i = 0; machines[i]; i++)

@@ -253,14 +657,29 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, if (!supported) { printf("%s: Machine type 0x%04x is not supported\n", __func__, nt->FileHeader.Machine);

• return EFI_LOAD_ERROR;
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

  }

• /* Calculate upper virtual address boundary */ num_sections = nt->FileHeader.NumberOfSections; sections = (void *)&nt->OptionalHeader + nt->FileHeader.SizeOfOptionalHeader;

• if (efi_size < ((void *)sections + sizeof(sections[0]) * num_sections

• 	- efi)) {
  

• printf("%s: Invalid number of sections: %d\n",
  

•        __func__, num_sections);
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

• }
• /* Authenticate an image */
• if (!efi_image_authenticate(efi, efi_size)) {

• ret = EFI_ACCESS_DENIED;
  

According to the UEFI specification LoadImage() should return EFI_SECURITY_VIOLATION in this case.

Further behaviour should depend on variables AuditMode and DeployedMode.

If authentication fails, you must update the configuration table identified by EFI_IMAGE_SECURITY_DATABASE_GUID containing the Image Execution Information. If the authentication succeeds you may enter a record.

It seems to me that in your patch series you are not creating the configuration table at all.

The content of the Image Execution Information Table should be used to decide if StartImage() may start an image. This is still missing in the patch series.

Best regards

Heinrich

• goto err;
  

• }
• /* Calculate upper virtual address boundary */ for (i = num_sections - 1; i >= 0; i--) { IMAGE_SECTION_HEADER *sec = &sections[i]; virt_size = max_t(unsigned long, virt_size,

@@ -279,7 +698,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, if (!efi_reloc) { printf("%s: Could not allocate %lu bytes\n", __func__, virt_size);

• 	return EFI_OUT_OF_RESOURCES;
  

• 	ret = EFI_OUT_OF_RESOURCES;
  

• 	goto err;
  

  } handle->entry = efi_reloc + opt->AddressOfEntryPoint; rel_size = opt->DataDirectory[rel_idx].Size;

@@ -295,7 +715,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, if (!efi_reloc) { printf("%s: Could not allocate %lu bytes\n", __func__, virt_size);

• 	return EFI_OUT_OF_RESOURCES;
  

• 	ret = EFI_OUT_OF_RESOURCES;
  

• 	goto err;
  

  } handle->entry = efi_reloc + opt->AddressOfEntryPoint; rel_size = opt->DataDirectory[rel_idx].Size;

@@ -304,13 +725,16 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, } else { printf("%s: Invalid optional header magic %x\n", __func__, nt->OptionalHeader.Magic);

• return EFI_LOAD_ERROR;
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

  }

  /* Copy PE headers */

• memcpy(efi_reloc, efi, sizeof(*dos) + sizeof(*nt)

•       + nt->FileHeader.SizeOfOptionalHeader
  

•       + num_sections * sizeof(IMAGE_SECTION_HEADER));
  

• memcpy(efi_reloc, efi,

•       sizeof(*dos)
  

•  + sizeof(*nt)
  

•  + nt->FileHeader.SizeOfOptionalHeader
  

•  + num_sections * sizeof(IMAGE_SECTION_HEADER));
  
  

  /* Load sections into RAM */ for (i = num_sections - 1; i >= 0; i--) {

@@ -327,7 +751,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, (unsigned long)image_base) != EFI_SUCCESS) { efi_free_pages((uintptr_t) efi_reloc, (virt_size + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT);

• return EFI_LOAD_ERROR;
  

• ret = EFI_LOAD_ERROR;
  

• goto err;
  

  }

  /* Flush cache */

@@ -340,4 +765,9 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, void *efi, loaded_image_info->image_size = virt_size;

return EFI_SUCCESS;

+err:

• free(new_efi);
• return ret; }