This function will be called from x509_check_for_self_signed() and pkcs7_verify_one(), which will be imported from linux in a later patch.

While it does exist in linux code and has a similar functionality of rsa_verify(), it calls further linux-specific interfaces inside. That could lead to more files being imported from linux.

So simply re-implement it here instead of re-using the code.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- include/crypto/public_key.h | 2 +- lib/crypto/public_key.c | 56 ++++++++++++++++++++++++++++++++++++- 2 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h index 436a1ee1ee64..3ba90fcc3483 100644 --- a/include/crypto/public_key.h +++ b/include/crypto/public_key.h @@ -82,9 +82,9 @@ extern int decrypt_blob(struct kernel_pkey_params *, const void *, void *); extern int create_signature(struct kernel_pkey_params *, const void *, void *); extern int verify_signature(const struct key *, const struct public_key_signature *); +#endif /* __UBOOT__ */

int public_key_verify_signature(const struct public_key *pkey, const struct public_key_signature *sig); -#endif /* !__UBOOT__ */

#endif /* _LINUX_PUBLIC_KEY_H */ diff --git a/lib/crypto/public_key.c b/lib/crypto/public_key.c index e12ebbb3d0c5..232e79d086ae 100644 --- a/lib/crypto/public_key.c +++ b/lib/crypto/public_key.c @@ -25,7 +25,10 @@ #include <keys/asymmetric-subtype.h> #endif #include <crypto/public_key.h> -#ifndef __UBOOT__ +#ifdef __UBOOT__ +#include <image.h> +#include <u-boot/rsa.h> +#else #include <crypto/akcipher.h> #endif

@@ -80,6 +83,57 @@ void public_key_signature_free(struct public_key_signature *sig) } EXPORT_SYMBOL_GPL(public_key_signature_free);

+/* + * Verify a signature using a public key. + */ +int public_key_verify_signature(const struct public_key *pkey, + const struct public_key_signature *sig) +{ + struct image_sign_info info; + struct image_region region; + int ret; + + pr_devel("==>%s()\n", __func__); + + if (!pkey || !sig) + return -EINVAL; + + if (pkey->key_is_private) + return -EINVAL; + + 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(sig->hash_algo, "sha1")) { + info.checksum = image_get_checksum_algo("sha1,rsa2048"); + info.name = "sha1,rsa2048"; + } else if (!strcmp(sig->hash_algo, "sha256")) { + info.checksum = image_get_checksum_algo("sha256,rsa2048"); + info.name = "sha256,rsa2048"; + } else { + pr_warn("unknown msg digest algo: %s\n", sig->hash_algo); + return -ENOPKG; + } + info.crypto = image_get_crypto_algo(info.name); + + info.key = pkey->key; + info.keylen = pkey->keylen; + + region.data = sig->digest; + region.size = sig->digest_size; + + if (rsa_verify_with_pkey(&info, sig->digest, sig->s, sig->s_size)) + ret = -EKEYREJECTED; + else + ret = 0; + + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} #else /* * Destroy a public key algorithm key.

When the file, x509_public_key.c, was imported from linux code in commit b4adf627d5b7 ("lib: crypto: add x509 parser"), x509_check_for_self_signed() was commented out for simplicity.

Now it need be enabled in order to make pkcs7_verify_one(), which will be imported in a later patch, functional.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- lib/crypto/x509_cert_parser.c | 2 -- lib/crypto/x509_public_key.c | 33 +++++++++++++++++++++++++-------- 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/lib/crypto/x509_cert_parser.c b/lib/crypto/x509_cert_parser.c index 5f984b9dfdae..eb24349460c2 100644 --- a/lib/crypto/x509_cert_parser.c +++ b/lib/crypto/x509_cert_parser.c @@ -142,12 +142,10 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen) } cert->id = kid;

-#ifndef __UBOOT__ /* Detect self-signed certificates */ ret = x509_check_for_self_signed(cert); if (ret < 0) goto error_decode; -#endif

kfree(ctx); return cert; diff --git a/lib/crypto/x509_public_key.c b/lib/crypto/x509_public_key.c index 571af9a0adf9..91810a864049 100644 --- a/lib/crypto/x509_public_key.c +++ b/lib/crypto/x509_public_key.c @@ -8,6 +8,7 @@ #define pr_fmt(fmt) "X.509: "fmt #ifdef __UBOOT__ #include <common.h> +#include <image.h> #include <dm/devres.h> #include <linux/compat.h> #include <linux/err.h> @@ -18,6 +19,7 @@ #include <linux/kernel.h> #ifdef __UBOOT__ #include <crypto/x509_parser.h> +#include <u-boot/rsa-checksum.h> #else #include <linux/slab.h> #include <keys/asymmetric-subtype.h> @@ -35,7 +37,9 @@ int x509_get_sig_params(struct x509_certificate *cert) { struct public_key_signature *sig = cert->sig; -#ifndef __UBOOT__ +#ifdef __UBOOT__ + struct image_region region; +#else struct crypto_shash *tfm; struct shash_desc *desc; size_t desc_size; @@ -63,12 +67,25 @@ int x509_get_sig_params(struct x509_certificate *cert) sig->s_size = cert->raw_sig_size;

#ifdef __UBOOT__ - /* - * Note: - * This part (filling sig->digest) should be implemented if - * x509_check_for_self_signed() is enabled x509_cert_parse(). - * Currently, this check won't affect UEFI secure boot. - */ + if (!sig->hash_algo) + return -ENOPKG; + if (!strcmp(sig->hash_algo, "sha256")) + sig->digest_size = SHA256_SUM_LEN; + else if (!strcmp(sig->hash_algo, "sha1")) + sig->digest_size = SHA1_SUM_LEN; + else + return -ENOPKG; + + sig->digest = calloc(1, sig->digest_size); + if (!sig->digest) + return -ENOMEM; + + region.data = cert->tbs; + region.size = cert->tbs_size; + hash_calculate(sig->hash_algo, &region, 1, sig->digest); + + /* TODO: is_hash_blacklisted()? */ + ret = 0; #else /* Allocate the hashing algorithm we're going to need and find out how @@ -118,7 +135,6 @@ error: return ret; }

-#ifndef __UBOOT__ /* * Check for self-signedness in an X.509 cert and if found, check the signature * immediately if we can. @@ -175,6 +191,7 @@ not_self_signed: return 0; }

+#ifndef __UBOOT__ /* * Attempt to parse a data blob for a key as an X509 certificate. */

This function was nullified when the file, pkcs7_verify.c, was imported because it calls further linux-specific interfaces inside, hence that could lead to more files being imported from linux.

We need this function in pkcs7_verify_one() and so simply re-implement it here instead of re-using the code.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- lib/crypto/pkcs7_verify.c | 84 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 81 insertions(+), 3 deletions(-)

diff --git a/lib/crypto/pkcs7_verify.c b/lib/crypto/pkcs7_verify.c index 1e8600f7faca..8b5cd7a443ae 100644 --- a/lib/crypto/pkcs7_verify.c +++ b/lib/crypto/pkcs7_verify.c @@ -17,7 +17,10 @@ #include <linux/err.h> #endif #include <linux/asn1.h> -#ifndef __UBOOT__ +#ifdef __UBOOT__ +#include <image.h> +#include <u-boot/rsa-checksum.h> +#else #include <crypto/hash.h> #include <crypto/hash_info.h> #endif @@ -35,9 +38,84 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7, struct pkcs7_signed_info *sinfo) { - return 0; + struct public_key_signature *sig = sinfo->sig; + struct image_region regions[2]; + int ret = 0; + + /* The digest was calculated already. */ + if (sig->digest) + return 0; + + if (!sinfo->sig->hash_algo) + return -ENOPKG; + if (!strcmp(sinfo->sig->hash_algo, "sha256")) + sig->digest_size = SHA256_SUM_LEN; + else if (!strcmp(sinfo->sig->hash_algo, "sha1")) + sig->digest_size = SHA1_SUM_LEN; + else + return -ENOPKG; + + sig->digest = calloc(1, sig->digest_size); + if (!sig->digest) { + pr_warn("Sig %u: Out of memory\n", sinfo->index); + return -ENOMEM; + } + + regions[0].data = pkcs7->data; + regions[0].size = pkcs7->data_len; + + /* Digest the message [RFC2315 9.3] */ + hash_calculate(sinfo->sig->hash_algo, regions, 1, sig->digest); + + /* However, if there are authenticated attributes, there must be a + * message digest attribute amongst them which corresponds to the + * digest we just calculated. + */ + if (sinfo->authattrs) { + u8 tag; + + if (!sinfo->msgdigest) { + pr_warn("Sig %u: No messageDigest\n", sinfo->index); + ret = -EKEYREJECTED; + goto error; + } + + if (sinfo->msgdigest_len != sig->digest_size) { + pr_debug("Sig %u: Invalid digest size (%u)\n", + sinfo->index, sinfo->msgdigest_len); + ret = -EBADMSG; + goto error; + } + + if (memcmp(sig->digest, sinfo->msgdigest, + sinfo->msgdigest_len) != 0) { + pr_debug("Sig %u: Message digest doesn't match\n", + sinfo->index); + ret = -EKEYREJECTED; + goto error; + } + + /* We then calculate anew, using the authenticated attributes + * as the contents of the digest instead. Note that we need to + * convert the attributes from a CONT.0 into a SET before we + * hash it. + */ + memset(sig->digest, 0, sig->digest_size); + + tag = 0x31; + regions[0].data = &tag; + regions[0].size = 1; + regions[1].data = sinfo->authattrs; + regions[1].size = sinfo->authattrs_len; + + hash_calculate(sinfo->sig->hash_algo, regions, 2, sig->digest); + + ret = 0; + } +error: + return ret; } -#else +#else /* !__UBOOT__ */ static int pkcs7_digest(struct pkcs7_message *pkcs7, struct pkcs7_signed_info *sinfo) {

In this commit, efi_signature_verify(with_sigdb) will be re-implemented using pcks7_verify_one() in order to support certificates chain, where the signer's certificate will be signed by an intermediate CA (certificate authority) and the latter's certificate will also be signed by another CA and so on.

What we need to do here is to search for certificates in a signature, build up a chain of certificates and verify one by one. pkcs7_verify_one() handles most of these steps except the last one.

pkcs7_verify_one() returns, if succeeded, the last certificate to verify, which can be either a self-signed one or one that should be signed by one of certificates in "db". Re-worked efi_signature_verify() will take care of this step.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- include/efi_loader.h | 8 +- lib/efi_loader/Kconfig | 1 + lib/efi_loader/efi_image_loader.c | 2 +- lib/efi_loader/efi_signature.c | 385 ++++++++++++++---------------- lib/efi_loader/efi_variable.c | 5 +- 5 files changed, 188 insertions(+), 213 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h index a95f9b339027..086528c305ef 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -767,10 +767,10 @@ bool efi_signature_lookup_digest(struct efi_image_regions *regs, bool efi_signature_verify_one(struct efi_image_regions *regs, struct pkcs7_message *msg, struct efi_signature_store *db); -bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, - struct pkcs7_message *msg, - struct efi_signature_store *db, - struct efi_signature_store *dbx); +bool efi_signature_verify(struct efi_image_regions *regs, + struct pkcs7_message *msg, + struct efi_signature_store *db, + struct efi_signature_store *dbx); bool efi_signature_check_signers(struct pkcs7_message *msg, struct efi_signature_store *dbx);

diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig index aad37b715505..5fc178180721 100644 --- a/lib/efi_loader/Kconfig +++ b/lib/efi_loader/Kconfig @@ -157,6 +157,7 @@ config EFI_SECURE_BOOT select ASYMMETRIC_PUBLIC_KEY_SUBTYPE select X509_CERTIFICATE_PARSER select PKCS7_MESSAGE_PARSER + select PKCS7_VERIFY default n 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 584a841116df..029bb035e5ce 100644 --- a/lib/efi_loader/efi_image_loader.c +++ b/lib/efi_loader/efi_image_loader.c @@ -642,7 +642,7 @@ static bool efi_image_authenticate(void *efi, size_t efi_size) }

/* try white-list */ - if (efi_signature_verify_with_sigdb(regs, msg, db, dbx)) + if (efi_signature_verify(regs, msg, db, dbx)) continue;

debug("Signature was not verified by "db"\n"); diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c index a87cbe520f56..55d584b20ac0 100644 --- a/lib/efi_loader/efi_signature.c +++ b/lib/efi_loader/efi_signature.c @@ -10,7 +10,9 @@ #include <image.h> #include <hexdump.h> #include <malloc.h> +#include <crypto/pkcs7.h> #include <crypto/pkcs7_parser.h> +#include <crypto/public_key.h> #include <crypto/x509_parser.h> #include <linux/compat.h> #include <linux/oid_registry.h> @@ -61,143 +63,6 @@ static bool efi_hash_regions(struct image_region *regs, int count, 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; - - regtmp.data = msg->data; - regtmp.size = msg->data_len; - - return efi_hash_regions(&regtmp, 1, hash, size); -} - -/** - * 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; - - EFI_PRINT("%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 { - EFI_PRINT("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 */ - EFI_PRINT("%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)) { - EFI_PRINT("%s: RSA verify authentication attribute\n", - __func__); - /* - * NOTE: This path will be executed only for - * PE image authentication - */ - - /* check if hash matches digest first */ - EFI_PRINT("checking msg digest first, len:0x%x\n", - ps_info->msgdigest_len); - -#ifdef DEBUG - EFI_PRINT("hash in database:\n"); - print_hex_dump(" ", DUMP_PREFIX_OFFSET, 16, 1, - ps_info->msgdigest, ps_info->msgdigest_len, - false); -#endif - /* against contentInfo first */ - hash = NULL; - if ((msg->data && efi_hash_msg_content(msg, &hash, &size)) || - /* for signed image */ - efi_hash_regions(regs->reg, regs->num, &hash, &size)) { - /* for authenticated variable */ - if (ps_info->msgdigest_len != size || - memcmp(hash, ps_info->msgdigest, size)) { - EFI_PRINT("Digest doesn't match\n"); - free(hash); - goto out; - } - - free(hash); - } else { - EFI_PRINT("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 { - EFI_PRINT("%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: - EFI_PRINT("%s: Exit, verified: %d\n", __func__, verified); - return verified; -} - /** * efi_signature_lookup_digest - search for an image's digest in sigdb * @regs: List of regions to be authenticated @@ -261,61 +126,127 @@ out: }

/** - * 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 + * efi_lookup_certificate - find a certificate within db + * @msg: Signature + * @db: Signature database * - * 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). + * Search signature database pointed to by @db and find a certificate + * pointed to by @cert. * - * Return: true if signature is verified, false if not + * Return: true if found, false otherwise. */ -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) +static bool efi_lookup_certificate(struct x509_certificate *cert, + struct efi_signature_store *db) { - struct x509_certificate *cert; + struct efi_signature_store *siglist; struct efi_sig_data *sig_data; - bool verified = false; + struct image_region reg[1]; + void *hash = NULL, *hash_tmp = NULL; + size_t size = 0; + bool found = false;

- EFI_PRINT("%s: Enter, %p, %p, %p, %p\n", __func__, - regs, signed_info, siglist, valid_cert); + EFI_PRINT("%s: Enter, %p, %p\n", __func__, cert, db);

- if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) { - EFI_PRINT("Signature type is not supported: %pUl\n", - &siglist->sig_type); + if (!cert || !db || !db->sig_data_list) 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 */ + /* + * TODO: identify a certificate using sha256 digest + * Is there any better way? + */ + /* calculate hash of TBSCertificate */ + reg[0].data = cert->tbs; + reg[0].size = cert->tbs_size; + if (!efi_hash_regions(reg, 1, &hash, &size)) + goto out;

- cert = x509_cert_parse(sig_data->data, sig_data->size); - if (IS_ERR(cert)) { - EFI_PRINT("Parsing x509 certificate failed\n"); - goto out; + EFI_PRINT("%s: searching for %s\n", __func__, cert->subject); + for (siglist = db; siglist; siglist = siglist->next) { + /* only with x509 certificate */ + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) + continue; + + for (sig_data = siglist->sig_data_list; sig_data; + sig_data = sig_data->next) { + struct x509_certificate *cert_tmp; + + cert_tmp = x509_cert_parse(sig_data->data, + sig_data->size); + if (!cert) + continue; + + reg[0].data = cert_tmp->tbs; + reg[0].size = cert_tmp->tbs_size; + if (!efi_hash_regions(reg, 1, &hash_tmp, NULL)) + goto out; + + x509_free_certificate(cert_tmp); + + if (!memcmp(hash, hash_tmp, size)) { + found = true; + goto out; + } } + } +out: + free(hash); + free(hash_tmp);

- verified = efi_signature_verify(regs, msg, signed_info, cert); + EFI_PRINT("%s: Exit, found: %d\n", __func__, found); + return found; +}

- if (verified) { - if (valid_cert) - *valid_cert = cert; - else - x509_free_certificate(cert); - break; +/** + * efi_verify_certificate - verify certificate's signature with database + * @signer: Certificate + * @db: Signature database + * @root: Certificate to verify @signer + * + * Determine if certificate pointed to by @signer may be verified + * by one of certificates in signature database pointed to by @db. + * + * Return: true if certificate is verified, false otherwise. + */ +static bool efi_verify_certificate(struct x509_certificate *signer, + struct efi_signature_store *db, + struct x509_certificate **root) +{ + struct efi_signature_store *siglist; + struct efi_sig_data *sig_data; + struct x509_certificate *cert; + bool verified = false; + int ret; + + EFI_PRINT("%s: Enter, %p, %p\n", __func__, signer, db); + + if (!signer || !db || !db->sig_data_list) + goto out; + + for (siglist = db; siglist; siglist = siglist->next) { + /* only with x509 certificate */ + if (guidcmp(&siglist->sig_type, &efi_guid_cert_x509)) + continue; + + for (sig_data = siglist->sig_data_list; sig_data; + sig_data = sig_data->next) { + cert = x509_cert_parse(sig_data->data, sig_data->size); + if (!cert) { + EFI_PRINT("Cannot parse x509 certificate\n"); + continue; + } + + ret = public_key_verify_signature(cert->pub, + signer->sig); + if (!ret) { + verified = true; + if (root) + *root = cert; + else + x509_free_certificate(cert); + goto out; + } + x509_free_certificate(cert); } - x509_free_certificate(cert); }

out: @@ -423,9 +354,9 @@ bool efi_signature_verify_one(struct efi_image_regions *regs, struct efi_signature_store *db) { struct pkcs7_signed_info *sinfo; - struct efi_signature_store *siglist; - struct x509_certificate *cert; + struct x509_certificate *signer; bool verified = false; + int ret;

EFI_PRINT("%s: Enter, %p, %p, %p\n", __func__, regs, msg, db);

@@ -440,13 +371,29 @@ bool efi_signature_verify_one(struct efi_image_regions *regs, EFI_PRINT("Signed Info: digest algo: %s, pkey algo: %s\n", sinfo->sig->hash_algo, sinfo->sig->pkey_algo);

- for (siglist = db; siglist; siglist = siglist->next) - if (efi_signature_verify_with_list(regs, msg, sinfo, - siglist, &cert)) { + EFI_PRINT("Verifying certificate chain\n"); + signer = NULL; + ret = pkcs7_verify_one(msg, sinfo, &signer); + if (ret == -ENOPKG) + continue; + + if (ret < 0 || !signer) + goto out; + + if (sinfo->blacklisted) + continue; + + EFI_PRINT("Verifying last certificate in chain\n"); + if (signer->self_signed) { + if (efi_lookup_certificate(signer, db)) { verified = true; goto out; } - EFI_PRINT("Valid certificate not in "db"\n"); + } else if (efi_verify_certificate(signer, db, NULL)) { + verified = true; + goto out; + } + EFI_PRINT("Valid certificate not in db\n"); }

out: @@ -454,8 +401,8 @@ out: return verified; }

-/** - * efi_signature_verify_with_sigdb - verify signatures with db and dbx +/* + * efi_signature_verify - verify signatures with db and dbx * @regs: List of regions to be authenticated * @msg: Signature * @db: Signature database for trusted certificates @@ -466,43 +413,71 @@ out: * * Return: true if verification for all signatures passed, false otherwise */ -bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs, - struct pkcs7_message *msg, - struct efi_signature_store *db, - struct efi_signature_store *dbx) +bool efi_signature_verify(struct efi_image_regions *regs, + struct pkcs7_message *msg, + struct efi_signature_store *db, + struct efi_signature_store *dbx) { - struct pkcs7_signed_info *info; - struct efi_signature_store *siglist; - struct x509_certificate *cert; + struct pkcs7_signed_info *sinfo; + struct x509_certificate *signer, *root; bool verified = false; + int ret;

EFI_PRINT("%s: Enter, %p, %p, %p, %p\n", __func__, regs, msg, db, dbx);

if (!regs || !msg || !db || !db->sig_data_list) goto out;

- for (info = msg->signed_infos; info; info = info->next) { + for (sinfo = msg->signed_infos; sinfo; sinfo = sinfo->next) { EFI_PRINT("Signed Info: digest algo: %s, pkey algo: %s\n", - info->sig->hash_algo, info->sig->pkey_algo); + sinfo->sig->hash_algo, sinfo->sig->pkey_algo);

- for (siglist = db; siglist; siglist = siglist->next) { - if (efi_signature_verify_with_list(regs, msg, info, - siglist, &cert)) - break; - } - if (!siglist) { - EFI_PRINT("Valid certificate not in "db"\n"); + /* + * only for authenticated variable. + * + * If this function is called for image, + * hash calculation will be done in + * pkcs7_verify_one(). + */ + if (!msg->data && + !efi_hash_regions(regs->reg, regs->num, + (void **)&sinfo->sig->digest, NULL)) { + EFI_PRINT("Digesting an image failed\n"); goto out; }

- if (!dbx || efi_signature_check_revocation(info, cert, dbx)) + EFI_PRINT("Verifying certificate chain\n"); + signer = NULL; + ret = pkcs7_verify_one(msg, sinfo, &signer); + if (ret == -ENOPKG) continue;

- EFI_PRINT("Certificate in "dbx"\n"); + if (ret < 0 || !signer) + goto out; + + if (sinfo->blacklisted) + goto out; + + EFI_PRINT("Verifying last certificate in chain\n"); + if (signer->self_signed) { + if (efi_lookup_certificate(signer, db)) + if (efi_signature_check_revocation(sinfo, + signer, dbx)) + continue; + } else if (efi_verify_certificate(signer, db, &root)) { + bool check; + + check = efi_signature_check_revocation(sinfo, root, + dbx); + x509_free_certificate(root); + if (check) + continue; + } + + EFI_PRINT("Certificate chain didn't reach trusted CA\n"); goto out; } verified = true; - out: EFI_PRINT("%s: Exit, verified: %d\n", __func__, verified); return verified; diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c index 90d740fbda2c..a2f3020c1847 100644 --- a/lib/efi_loader/efi_variable.c +++ b/lib/efi_loader/efi_variable.c @@ -558,12 +558,11 @@ static efi_status_t efi_variable_authenticate(u16 *variable, }

/* verify signature */ - if (efi_signature_verify_with_sigdb(regs, var_sig, truststore, NULL)) { + if (efi_signature_verify(regs, var_sig, truststore, NULL)) { EFI_PRINT("Verified\n"); } else { if (truststore2 && - efi_signature_verify_with_sigdb(regs, var_sig, - truststore2, NULL)) { + efi_signature_verify(regs, var_sig, truststore2, NULL)) { EFI_PRINT("Verified\n"); } else { EFI_PRINT("Verifying variable's signature failed\n");

In this test case, an image may have a signature with additional intermediate certificates. A chain of trust will be followed and all the certificates in the middle of chain must be verified before loading.

Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- test/py/tests/test_efi_secboot/conftest.py | 138 +++++++++++++++++- test/py/tests/test_efi_secboot/defs.py | 11 +- test/py/tests/test_efi_secboot/openssl.cnf | 48 ++++++ .../test_efi_secboot/test_signed_intca.py | 135 +++++++++++++++++ 4 files changed, 329 insertions(+), 3 deletions(-) create mode 100644 test/py/tests/test_efi_secboot/openssl.cnf create mode 100644 test/py/tests/test_efi_secboot/test_signed_intca.py

diff --git a/test/py/tests/test_efi_secboot/conftest.py b/test/py/tests/test_efi_secboot/conftest.py index 5ac0389064e8..6c5415021610 100644 --- a/test/py/tests/test_efi_secboot/conftest.py +++ b/test/py/tests/test_efi_secboot/conftest.py @@ -34,7 +34,7 @@ def efi_boot_env(request, u_boot_config): global HELLO_PATH

image_path = u_boot_config.persistent_data_dir - image_path = image_path + '/' + EFI_SECBOOT_IMAGE_NAME + image_path = image_path + '/' + EFI_SECBOOT_IMAGE_NAME + '.img' image_size = EFI_SECBOOT_IMAGE_SIZE part_size = EFI_SECBOOT_PART_SIZE fs_type = EFI_SECBOOT_FS_TYPE @@ -43,7 +43,7 @@ def efi_boot_env(request, u_boot_config): HELLO_PATH = u_boot_config.build_dir + '/lib/efi_loader/helloworld.efi'

try: - mnt_point = u_boot_config.persistent_data_dir + '/mnt_efisecure' + mnt_point = u_boot_config.persistent_data_dir + MNTPNT check_call('mkdir -p {}'.format(mnt_point), shell=True)

# create a disk/partition @@ -153,3 +153,137 @@ def efi_boot_env(request, u_boot_config): yield image_path finally: call('rm -f %s' % image_path, shell=True) + +# +# Fixture for UEFI secure boot test of intermediate certificates +# +@pytest.fixture(scope='session') +def efi_boot_env_intca(request, u_boot_config): + """Set up a file system to be used in UEFI secure boot test + of intermediate certificates. + + Args: + request: Pytest request object. + u_boot_config: U-boot configuration. + + Return: + A path to disk image to be used for testing + """ + global HELLO_PATH + + image_path = u_boot_config.persistent_data_dir + image_path = image_path + '/' + EFI_SECBOOT_IMAGE_NAME + '_intca.img' + image_size = EFI_SECBOOT_IMAGE_SIZE + part_size = EFI_SECBOOT_PART_SIZE + fs_type = EFI_SECBOOT_FS_TYPE + + if HELLO_PATH == '': + HELLO_PATH = u_boot_config.build_dir + '/lib/efi_loader/helloworld.efi' + + try: + mnt_point = u_boot_config.persistent_data_dir + MNTPNT + check_call('mkdir -p {}'.format(mnt_point), shell=True) + + # create a disk/partition + check_call('dd if=/dev/zero of=%s bs=1MiB count=%d' + % (image_path, image_size), shell=True) + check_call('sgdisk %s -n 1:0:+%dMiB' + % (image_path, part_size), shell=True) + # create a file system + check_call('dd if=/dev/zero of=%s.tmp bs=1MiB count=%d' + % (image_path, part_size), shell=True) + check_call('mkfs -t %s %s.tmp' % (fs_type, image_path), shell=True) + check_call('dd if=%s.tmp of=%s bs=1MiB seek=1 count=%d conv=notrunc' + % (image_path, image_path, 1), shell=True) + check_call('rm %s.tmp' % image_path, shell=True) + loop_dev = check_output('sudo losetup -o 1MiB --sizelimit %dMiB --show -f %s | tr -d "\n"' + % (part_size, image_path), shell=True).decode() + check_output('sudo mount -t %s -o umask=000 %s %s' + % (fs_type, loop_dev, mnt_point), shell=True) + + # Create signature database + ## PK + check_call('cd %s; openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=TEST_PK/ -keyout PK.key -out PK.crt -nodes -days 365' + % mnt_point, shell=True) + check_call('cd %s; %scert-to-efi-sig-list -g %s PK.crt PK.esl; %ssign-efi-sig-list -c PK.crt -k PK.key PK PK.esl PK.auth' + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH), + shell=True) + ## KEK + check_call('cd %s; openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=TEST_KEK/ -keyout KEK.key -out KEK.crt -nodes -days 365' + % mnt_point, shell=True) + check_call('cd %s; %scert-to-efi-sig-list -g %s KEK.crt KEK.esl; %ssign-efi-sig-list -c PK.crt -k PK.key KEK KEK.esl KEK.auth' + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH), + shell=True) + + # We will have three-tier hierarchy of certificates: + # TestRoot: Root CA (self-signed) + # TestSub: Intermediate CA (signed by Root CA) + # TestCert: User certificate (signed by Intermediate CA, and used + # for signing an image) + # + # NOTE: + # I consulted the following EDK2 document for certificate options: + # BaseTools/Source/Python/Pkcs7Sign/Readme.md + # Please not use them as they are in product system. They are + # for test purpose only. + + # TestRoot + check_call('cp %s/test/py/tests/test_efi_secboot/openssl.cnf %s' % (u_boot_config.source_dir, mnt_point), shell=True) + check_call('cd %s; openssl genrsa -out TestRoot.key 2048; openssl req --config openssl.cnf -extensions v3_ca -new -x509 -days 365 -key TestRoot.key -out TestRoot.crt -subj "/CN=TEST_root/"; touch index.txt' % mnt_point, shell=True) + # TestSub + check_call('cd %s; openssl genrsa -out TestSub.key 2048; openssl req -new -key TestSub.key -out TestSub.csr -subj "/CN=TEST_sub/"; openssl ca --config openssl.cnf -in TestSub.csr -out TestSub.crt -extensions v3_int_ca -days 365 -batch -rand_serial -cert TestRoot.crt -keyfile TestRoot.key' % mnt_point, shell=True) + # TestCert + check_call('cd %s; openssl genrsa -out TestCert.key 2048; openssl req -new -key TestCert.key -out TestCert.csr -subj "/CN=TEST_cert/"; openssl ca --config openssl.cnf -in TestCert.csr -out TestCert.crt -extensions usr_cert -days 365 -batch -rand_serial -cert TestSub.crt -keyfile TestSub.key' % mnt_point, shell=True) + ## db + # for TestCert + check_call('cd %s; %scert-to-efi-sig-list -g %s TestCert.crt TestCert.esl; %ssign-efi-sig-list -c KEK.crt -k KEK.key db TestCert.esl db_a.auth' + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH), + shell=True) + # for TestSub + check_call('cd %s; %scert-to-efi-sig-list -g %s TestSub.crt TestSub.esl; %ssign-efi-sig-list -c KEK.crt -k KEK.key db TestSub.esl db_b.auth' + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH), + shell=True) + # for TestRoot + check_call('cd %s; %scert-to-efi-sig-list -g %s TestRoot.crt TestRoot.esl; %ssign-efi-sig-list -c KEK.crt -k KEK.key db TestRoot.esl db_c.auth' + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH), + shell=True) + ## dbx (hash of certificate with revocation time) + # for TestCert + check_call('cd %s; %scert-to-efi-hash-list -g %s -t 0 -s 256 TestCert.crt TestCert.crl; %ssign-efi-sig-list -c KEK.crt -k KEK.key dbx TestCert.crl dbx_a.auth' + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH), + shell=True) + # for TestSub + check_call('cd %s; %scert-to-efi-hash-list -g %s -t 0 -s 256 TestSub.crt TestSub.crl; %ssign-efi-sig-list -c KEK.crt -k KEK.key dbx TestSub.crl dbx_b.auth' + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH), + shell=True) + # for TestRoot + check_call('cd %s; %scert-to-efi-hash-list -g %s -t 0 -s 256 TestRoot.crt TestRoot.crl; %ssign-efi-sig-list -c KEK.crt -k KEK.key dbx TestRoot.crl dbx_c.auth' + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH), + shell=True) + + # Sign image + # additional intermediate certificates may be included + # in SignedData + + check_call('cp %s %s' % (HELLO_PATH, mnt_point), shell=True) + ## signed by TestCert + check_call('cd %s; %ssbsign --key TestCert.key --cert TestCert.crt --out helloworld.efi.signed_a helloworld.efi' + % (mnt_point, SBSIGN_PATH), shell=True) + ## signed by TestCert with TestSub in signature + check_call('cd %s; %ssbsign --key TestCert.key --cert TestCert.crt --addcert TestSub.crt --out helloworld.efi.signed_ab helloworld.efi' + % (mnt_point, SBSIGN_PATH), shell=True) + ## signed by TestCert with TestSub and TestRoot in signature + check_call('cd %s; cat TestSub.crt TestRoot.crt > TestSubRoot.crt; %ssbsign --key TestCert.key --cert TestCert.crt --addcert TestSubRoot.crt --out helloworld.efi.signed_abc helloworld.efi' + % (mnt_point, SBSIGN_PATH), shell=True) + + # Clean-up + check_call('sudo umount %s' % loop_dev, shell=True) + check_call('sudo losetup -d %s' % loop_dev, shell=True) + + except CalledProcessError as e: + pytest.skip('Setup failed: %s' % e.cmd) + return + else: + yield image_path + finally: + call('rm -f %s' % image_path, shell=True) diff --git a/test/py/tests/test_efi_secboot/defs.py b/test/py/tests/test_efi_secboot/defs.py index d6222809c547..2c3a82d1681b 100644 --- a/test/py/tests/test_efi_secboot/defs.py +++ b/test/py/tests/test_efi_secboot/defs.py @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0+

# Disk image name -EFI_SECBOOT_IMAGE_NAME='test_efi_secboot.img' +EFI_SECBOOT_IMAGE_NAME='test_efi_secboot'

# Size in MiB EFI_SECBOOT_IMAGE_SIZE=16 @@ -10,12 +10,21 @@ EFI_SECBOOT_PART_SIZE=8 # Partition file system type EFI_SECBOOT_FS_TYPE='vfat'

+# Mount point +MNTPNT='mnt' + # Owner guid GUID='11111111-2222-3333-4444-123456789abc'

# v1.5.1 or earlier of efitools has a bug in sha256 calculation, and # you need build a newer version on your own. +# The path must terminate with '/'. EFITOOLS_PATH=''

+# "--addcert" option of sbsign must be available, otherwise +# you need build a newer version on your own. +# The path must terminate with '/'. +SBSIGN_PATH='/home/akashi/arm/misc/sbsigntools/src/' + # Hello World application for sandbox HELLO_PATH='' diff --git a/test/py/tests/test_efi_secboot/openssl.cnf b/test/py/tests/test_efi_secboot/openssl.cnf new file mode 100644 index 000000000000..f684f1df7e69 --- /dev/null +++ b/test/py/tests/test_efi_secboot/openssl.cnf @@ -0,0 +1,48 @@ +[ ca ] +default_ca = CA_default + +[ CA_default ] +new_certs_dir = . +database = ./index.txt +serial = ./serial +default_md = sha256 +policy = policy_min + +[ req ] +distinguished_name = def_distinguished_name + +[def_distinguished_name] + +# Extensions +# -addext " ... = ..." +# +[ v3_ca ] + # Extensions for a typical Root CA. + basicConstraints = critical,CA:TRUE + keyUsage = critical, digitalSignature, cRLSign, keyCertSign + subjectKeyIdentifier = hash + authorityKeyIdentifier = keyid:always,issuer + +[ v3_int_ca ] + # Extensions for a typical intermediate CA. + basicConstraints = critical, CA:TRUE + keyUsage = critical, digitalSignature, cRLSign, keyCertSign + subjectKeyIdentifier = hash + authorityKeyIdentifier = keyid:always,issuer + +[ usr_cert ] + # Extensions for user end certificates. + basicConstraints = CA:FALSE + keyUsage = critical, nonRepudiation, digitalSignature, keyEncipherment + extendedKeyUsage = clientAuth, emailProtection + subjectKeyIdentifier = hash + authorityKeyIdentifier = keyid,issuer + +[ policy_min ] + countryName = optional + stateOrProvinceName = optional + localityName = optional + organizationName = optional + organizationalUnitName = optional + commonName = supplied + emailAddress = optional diff --git a/test/py/tests/test_efi_secboot/test_signed_intca.py b/test/py/tests/test_efi_secboot/test_signed_intca.py new file mode 100644 index 000000000000..8a3b152dc12f --- /dev/null +++ b/test/py/tests/test_efi_secboot/test_signed_intca.py @@ -0,0 +1,135 @@ +# SPDX-License-Identifier: GPL-2.0+ +# Copyright (c) 2020, Linaro Limited +# Author: AKASHI Takahiro takahiro.akashi@linaro.org +# +# U-Boot UEFI: Image Authentication Test (signature with certificates chain) + +""" +This test verifies image authentication for a signed image which is signed +by user certificate and contains additional intermediate certificates in its +signature. +""" + +import pytest +from defs import * + +@pytest.mark.boardspec('sandbox') +@pytest.mark.buildconfigspec('efi_secure_boot') +@pytest.mark.buildconfigspec('cmd_efidebug') +@pytest.mark.buildconfigspec('cmd_fat') +@pytest.mark.buildconfigspec('cmd_nvedit_efi') +@pytest.mark.slow +class TestEfiSignedImageExt(object): + def test_efi_signed_image_ext1(self, u_boot_console, efi_boot_env_intca): + """ + Test Case 1 - authenticated by root CA in db + """ + u_boot_console.restart_uboot() + disk_img = efi_boot_env_intca + with u_boot_console.log.section('Test Case 1a'): + # Test Case 1a, with no Int CA and not authenticated by root CA + output = u_boot_console.run_command_list([ + 'host bind 0 %s' % disk_img, + 'fatload host 0:1 4000000 db_c.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize db', + 'fatload host 0:1 4000000 KEK.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize KEK', + 'fatload host 0:1 4000000 PK.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize PK']) + assert(not 'Failed to set EFI variable' in ''.join(output)) + + output = u_boot_console.run_command_list([ + 'efidebug boot add 1 HELLO_a host 0:1 /helloworld.efi.signed_a ""', + 'efidebug boot next 1', + 'efidebug test bootmgr']) + assert(''HELLO_a' failed' in ''.join(output)) + assert('efi_start_image() returned: 26' in ''.join(output)) + + with u_boot_console.log.section('Test Case 1b'): + # Test Case 1b, signed and authenticated by root CA + output = u_boot_console.run_command_list([ + 'efidebug boot add 2 HELLO_ab host 0:1 /helloworld.efi.signed_ab ""', + 'efidebug boot next 2', + 'bootefi bootmgr']) + assert('Hello, world!' in ''.join(output)) + + def test_efi_signed_image_ext2(self, u_boot_console, efi_boot_env_intca): + """ + Test Case 2 - authenticated by root CA in db + """ + u_boot_console.restart_uboot() + disk_img = efi_boot_env_intca + with u_boot_console.log.section('Test Case 2a'): + # Test Case 2a, unsigned and not authenticated by root CA + output = u_boot_console.run_command_list([ + 'host bind 0 %s' % disk_img, + 'fatload host 0:1 4000000 KEK.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize KEK', + 'fatload host 0:1 4000000 PK.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize PK']) + assert(not 'Failed to set EFI variable' in ''.join(output)) + + output = u_boot_console.run_command_list([ + 'efidebug boot add 1 HELLO_abc host 0:1 /helloworld.efi.signed_abc ""', + 'efidebug boot next 1', + 'efidebug test bootmgr']) + assert(''HELLO_abc' failed' in ''.join(output)) + assert('efi_start_image() returned: 26' in ''.join(output)) + + with u_boot_console.log.section('Test Case 2b'): + # Test Case 2b, signed and authenticated by root CA + output = u_boot_console.run_command_list([ + 'fatload host 0:1 4000000 db_b.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize db', + 'efidebug boot next 1', + 'efidebug test bootmgr']) + assert(''HELLO_abc' failed' in ''.join(output)) + assert('efi_start_image() returned: 26' in ''.join(output)) + + with u_boot_console.log.section('Test Case 2c'): + # Test Case 2c, signed and authenticated by root CA + output = u_boot_console.run_command_list([ + 'fatload host 0:1 4000000 db_c.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize db', + 'efidebug boot next 1', + 'efidebug test bootmgr']) + assert('Hello, world!' in ''.join(output)) + + def test_efi_signed_image_ext3(self, u_boot_console, efi_boot_env_intca): + """ + Test Case 3 - revoked by dbx + """ + u_boot_console.restart_uboot() + disk_img = efi_boot_env_intca + with u_boot_console.log.section('Test Case 3a'): + # Test Case 3a, revoked by root CA in dbx + output = u_boot_console.run_command_list([ + 'host bind 0 %s' % disk_img, + 'fatload host 0:1 4000000 dbx_c.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize dbx', + 'fatload host 0:1 4000000 db_c.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize db', + 'fatload host 0:1 4000000 KEK.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize KEK', + 'fatload host 0:1 4000000 PK.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize PK']) + assert(not 'Failed to set EFI variable' in ''.join(output)) + + output = u_boot_console.run_command_list([ + 'efidebug boot add 1 HELLO_abc host 0:1 /helloworld.efi.signed_abc ""', + 'efidebug boot next 1', + 'efidebug test bootmgr']) + assert(''HELLO_abc' failed' in ''.join(output)) + assert('efi_start_image() returned: 26' in ''.join(output)) + + with u_boot_console.log.section('Test Case 3b'): + # Test Case 3b, revoked by int CA in dbx + output = u_boot_console.run_command_list([ + 'fatload host 0:1 4000000 dbx_b.auth', + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize dbx', + 'efidebug boot next 1', + 'efidebug test bootmgr']) + assert('Hello, world!' in ''.join(output)) + # Or, + # assert(''HELLO_abc' failed' in ''.join(output)) + # assert('efi_start_image() returned: 26' in ''.join(output))