From bda850cd214e90b1be0cc25bc48c4f6ac53eb543 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 6 Apr 2016 16:14:24 +0100 Subject: [PATCH] PKCS#7: Make trust determination dependent on contents of trust keyring Make the determination of the trustworthiness of a key dependent on whether a key that can verify it is present in the supplied ring of trusted keys rather than whether or not the verifying key has KEY_FLAG_TRUSTED set. verify_pkcs7_signature() will return -ENOKEY if the PKCS#7 message trust chain cannot be verified. Signed-off-by: David Howells --- certs/system_keyring.c | 13 ++++--------- crypto/asymmetric_keys/pkcs7_key_type.c | 2 +- crypto/asymmetric_keys/pkcs7_parser.h | 1 - crypto/asymmetric_keys/pkcs7_trust.c | 18 +++--------------- crypto/asymmetric_keys/verify_pefile.c | 2 +- crypto/asymmetric_keys/x509_parser.h | 1 - include/crypto/pkcs7.h | 3 +-- include/linux/verification.h | 1 - kernel/module_signing.c | 2 +- 9 files changed, 11 insertions(+), 32 deletions(-) diff --git a/certs/system_keyring.c b/certs/system_keyring.c index a83bffedc0aa..dc18869ff680 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -121,7 +121,6 @@ late_initcall(load_system_certificate_list); int verify_pkcs7_signature(const void *data, size_t len, const void *raw_pkcs7, size_t pkcs7_len, struct key *trusted_keys, - int untrusted_error, enum key_being_used_for usage, int (*view_content)(void *ctx, const void *data, size_t len, @@ -129,7 +128,6 @@ int verify_pkcs7_signature(const void *data, size_t len, void *ctx) { struct pkcs7_message *pkcs7; - bool trusted; int ret; pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len); @@ -149,13 +147,10 @@ int verify_pkcs7_signature(const void *data, size_t len, if (!trusted_keys) trusted_keys = system_trusted_keyring; - ret = pkcs7_validate_trust(pkcs7, trusted_keys, &trusted); - if (ret < 0) - goto error; - - if (!trusted && untrusted_error) { - pr_err("PKCS#7 signature not signed with a trusted key\n"); - ret = untrusted_error; + ret = pkcs7_validate_trust(pkcs7, trusted_keys); + if (ret < 0) { + if (ret == -ENOKEY) + pr_err("PKCS#7 signature not signed with a trusted key\n"); goto error; } diff --git a/crypto/asymmetric_keys/pkcs7_key_type.c b/crypto/asymmetric_keys/pkcs7_key_type.c index ab9bf5363ecd..3b92523882e5 100644 --- a/crypto/asymmetric_keys/pkcs7_key_type.c +++ b/crypto/asymmetric_keys/pkcs7_key_type.c @@ -62,7 +62,7 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep) return verify_pkcs7_signature(NULL, 0, prep->data, prep->datalen, - NULL, -ENOKEY, usage, + NULL, usage, pkcs7_view_content, prep); } diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h index d5eec31e95b6..f4e81074f5e0 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.h +++ b/crypto/asymmetric_keys/pkcs7_parser.h @@ -22,7 +22,6 @@ struct pkcs7_signed_info { struct pkcs7_signed_info *next; struct x509_certificate *signer; /* Signing certificate (in msg->certs) */ unsigned index; - bool trusted; bool unsupported_crypto; /* T if not usable due to missing crypto */ /* Message digest - the digest of the Content Data (or NULL) */ diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c index b9a5487cd82d..36e77cb07bd0 100644 --- a/crypto/asymmetric_keys/pkcs7_trust.c +++ b/crypto/asymmetric_keys/pkcs7_trust.c @@ -30,7 +30,6 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, struct public_key_signature *sig = sinfo->sig; struct x509_certificate *x509, *last = NULL, *p; struct key *key; - bool trusted; int ret; kenter(",%u,", sinfo->index); @@ -42,10 +41,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, for (x509 = sinfo->signer; x509; x509 = x509->signer) { if (x509->seen) { - if (x509->verified) { - trusted = x509->trusted; + if (x509->verified) goto verified; - } kleave(" = -ENOKEY [cached]"); return -ENOKEY; } @@ -122,7 +119,6 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, matched: ret = verify_signature(key, sig); - trusted = test_bit(KEY_FLAG_TRUSTED, &key->flags); key_put(key); if (ret < 0) { if (ret == -ENOMEM) @@ -134,12 +130,9 @@ matched: verified: if (x509) { x509->verified = true; - for (p = sinfo->signer; p != x509; p = p->signer) { + for (p = sinfo->signer; p != x509; p = p->signer) p->verified = true; - p->trusted = trusted; - } } - sinfo->trusted = trusted; kleave(" = 0"); return 0; } @@ -148,7 +141,6 @@ verified: * pkcs7_validate_trust - Validate PKCS#7 trust chain * @pkcs7: The PKCS#7 certificate to validate * @trust_keyring: Signing certificates to use as starting points - * @_trusted: Set to true if trustworth, false otherwise * * Validate that the certificate chain inside the PKCS#7 message intersects * keys we already know and trust. @@ -170,16 +162,13 @@ verified: * May also return -ENOMEM. */ int pkcs7_validate_trust(struct pkcs7_message *pkcs7, - struct key *trust_keyring, - bool *_trusted) + struct key *trust_keyring) { struct pkcs7_signed_info *sinfo; struct x509_certificate *p; int cached_ret = -ENOKEY; int ret; - *_trusted = false; - for (p = pkcs7->certs; p; p = p->next) p->seen = false; @@ -193,7 +182,6 @@ int pkcs7_validate_trust(struct pkcs7_message *pkcs7, cached_ret = -ENOPKG; continue; case 0: - *_trusted |= sinfo->trusted; cached_ret = 0; continue; default: diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c index 265351075b0e..672a94c2c3ff 100644 --- a/crypto/asymmetric_keys/verify_pefile.c +++ b/crypto/asymmetric_keys/verify_pefile.c @@ -436,7 +436,7 @@ int verify_pefile_signature(const void *pebuf, unsigned pelen, ret = verify_pkcs7_signature(NULL, 0, pebuf + ctx.sig_offset, ctx.sig_len, - trusted_keys, -EKEYREJECTED, usage, + trusted_keys, usage, mscode_parse, &ctx); if (ret < 0) goto error; diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h index f24f4d808e7f..05eef1c68881 100644 --- a/crypto/asymmetric_keys/x509_parser.h +++ b/crypto/asymmetric_keys/x509_parser.h @@ -39,7 +39,6 @@ struct x509_certificate { unsigned index; bool seen; /* Infinite recursion prevention */ bool verified; - bool trusted; bool self_signed; /* T if self-signed (check unsupported_sig too) */ bool unsupported_key; /* T if key uses unsupported crypto */ bool unsupported_sig; /* T if signature uses unsupported crypto */ diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h index 8323e3e57131..583f199400a3 100644 --- a/include/crypto/pkcs7.h +++ b/include/crypto/pkcs7.h @@ -33,8 +33,7 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, * pkcs7_trust.c */ extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7, - struct key *trust_keyring, - bool *_trusted); + struct key *trust_keyring); /* * pkcs7_verify.c diff --git a/include/linux/verification.h b/include/linux/verification.h index bb0fcf941cb7..a10549a6c7cd 100644 --- a/include/linux/verification.h +++ b/include/linux/verification.h @@ -33,7 +33,6 @@ struct key; extern int verify_pkcs7_signature(const void *data, size_t len, const void *raw_pkcs7, size_t pkcs7_len, struct key *trusted_keys, - int untrusted_error, enum key_being_used_for usage, int (*view_content)(void *ctx, const void *data, size_t len, diff --git a/kernel/module_signing.c b/kernel/module_signing.c index 593aace88a02..6a64e03b9f44 100644 --- a/kernel/module_signing.c +++ b/kernel/module_signing.c @@ -81,6 +81,6 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen) } return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len, - NULL, -ENOKEY, VERIFYING_MODULE_SIGNATURE, + NULL, VERIFYING_MODULE_SIGNATURE, NULL, NULL); } -- 2.20.1