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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 3/9] PKCS#7: Handle blacklisted certificates From: David Howells To: keyrings@vger.kernel.org Cc: dhowells@redhat.com, matthew.garrett@nebula.com, linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 16 Nov 2016 18:11:06 +0000 Message-ID: <147931986662.16460.18285955227981592741.stgit@warthog.procyon.org.uk> In-Reply-To: <147931984418.16460.6639993676886095760.stgit@warthog.procyon.org.uk> References: <147931984418.16460.6639993676886095760.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 16 Nov 2016 18:11:08 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP PKCS#7: Handle certificates that are blacklisted when verifying the chain of trust on the signatures on a PKCS#7 message. Signed-off-by: David Howells --- crypto/asymmetric_keys/pkcs7_parser.h | 1 + crypto/asymmetric_keys/pkcs7_verify.c | 32 ++++++++++++++++++++++++-------- 2 files changed, 25 insertions(+), 8 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h index f4e81074f5e0..ac341e19e530 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.h +++ b/crypto/asymmetric_keys/pkcs7_parser.h @@ -23,6 +23,7 @@ struct pkcs7_signed_info { struct x509_certificate *signer; /* Signing certificate (in msg->certs) */ unsigned index; bool unsupported_crypto; /* T if not usable due to missing crypto */ + bool blacklisted; /* Message digest - the digest of the Content Data (or NULL) */ const void *msgdigest; diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c index 2ffd69769466..2d93d9eccb4d 100644 --- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -190,6 +190,18 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, x509->subject, x509->raw_serial_size, x509->raw_serial); x509->seen = true; + + if (x509->blacklisted) { + /* If this cert is blacklisted, then mark everything + * that depends on this as blacklisted too. + */ + sinfo->blacklisted = true; + for (p = sinfo->signer; p != x509; p = p->signer) + p->blacklisted = true; + pr_debug("- blacklisted\n"); + return 0; + } + if (x509->unsupported_key) goto unsupported_crypto_in_x509; @@ -357,17 +369,19 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7, * * (*) -EBADMSG if some part of the message was invalid, or: * - * (*) -ENOPKG if none of the signature chains are verifiable because suitable - * crypto modules couldn't be found, or: + * (*) 0 if no signature chains were found to be blacklisted or to contain + * unsupported crypto, or: * - * (*) 0 if all the signature chains that don't incur -ENOPKG can be verified - * (note that a signature chain may be of zero length), or: + * (*) -EKEYREJECTED if a blacklisted key was encountered, or: + * + * (*) -ENOPKG if none of the signature chains are verifiable because suitable + * crypto modules couldn't be found. */ int pkcs7_verify(struct pkcs7_message *pkcs7, enum key_being_used_for usage) { struct pkcs7_signed_info *sinfo; - int enopkg = -ENOPKG; + int actual_ret = -ENOPKG; int ret; kenter(""); @@ -412,6 +426,8 @@ int pkcs7_verify(struct pkcs7_message *pkcs7, for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) { ret = pkcs7_verify_one(pkcs7, sinfo); + if (sinfo->blacklisted && actual_ret == -ENOPKG) + actual_ret = -EKEYREJECTED; if (ret < 0) { if (ret == -ENOPKG) { sinfo->unsupported_crypto = true; @@ -420,11 +436,11 @@ int pkcs7_verify(struct pkcs7_message *pkcs7, kleave(" = %d", ret); return ret; } - enopkg = 0; + actual_ret = 0; } - kleave(" = %d", enopkg); - return enopkg; + kleave(" = %d", actual_ret); + return actual_ret; } EXPORT_SYMBOL_GPL(pkcs7_verify);