From bc501570109e7837e1de1689de1eec9420e4cf89 Mon Sep 17 00:00:00 2001 From: "Dr. Stephen Henson" Date: Fri, 5 Mar 2004 17:16:35 +0000 Subject: [PATCH] Various X509 fixes. Disable broken certificate workarounds when X509_V_FLAG_X509_STRICT is set. Check for CRLSign in CRL issuer certificates. Reject CRLs with unhandled (any) critical extensions. --- CHANGES | 8 ++++++ crypto/x509/x509_txt.c | 6 +++++ crypto/x509/x509_vfy.c | 55 +++++++++++++++++++++++++++++++++++------ crypto/x509/x509_vfy.h | 19 ++++++++++---- crypto/x509v3/v3_purp.c | 5 ++-- 5 files changed, 79 insertions(+), 14 deletions(-) diff --git a/CHANGES b/CHANGES index bea8e76838..19803f2935 100644 --- a/CHANGES +++ b/CHANGES @@ -617,6 +617,14 @@ Changes between 0.9.7c and 0.9.7d [xx XXX XXXX] + *) X509 verify fixes. Disable broken certificate workarounds when + X509_V_FLAGS_X509_STRICT is set. Check CRL issuer has cRLSign set if + keyUsage extension present. Don't accept CRLs with unhandled critical + extensions: since verify currently doesn't process CRL extensions this + rejects a CRL with *any* critical extensions. Add new verify error codes + for these cases. + [Steve Henson] + *) When creating an OCSP nonce use an OCTET STRING inside the extnValue. A clarification of RFC2560 will require the use of OCTET STRINGs and some implementations cannot handle the current raw format. Since OpenSSL diff --git a/crypto/x509/x509_txt.c b/crypto/x509/x509_txt.c index 5a945a70fb..e31ebc6741 100644 --- a/crypto/x509/x509_txt.c +++ b/crypto/x509/x509_txt.c @@ -147,6 +147,12 @@ const char *X509_verify_cert_error_string(long n) case X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION: return("unhandled critical extension"); + case X509_V_ERR_KEYUSAGE_NO_CRL_SIGN: + return("key usage does not include CRL signing"); + + case X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION: + return("unhandled critical CRL extension"); + default: BIO_snprintf(buf,sizeof buf,"error number %ld",n); return(buf); diff --git a/crypto/x509/x509_vfy.c b/crypto/x509/x509_vfy.c index 2bb21b443e..2e4d0b823a 100644 --- a/crypto/x509/x509_vfy.c +++ b/crypto/x509/x509_vfy.c @@ -383,6 +383,7 @@ static int check_chain_purpose(X509_STORE_CTX *ctx) /* Check all untrusted certificates */ for (i = 0; i < ctx->last_untrusted; i++) { + int ret; x = sk_X509_value(ctx->chain, i); if (!(ctx->flags & X509_V_FLAG_IGNORE_CRITICAL) && (x->ex_flags & EXFLAG_CRITICAL)) @@ -393,7 +394,10 @@ static int check_chain_purpose(X509_STORE_CTX *ctx) ok=cb(0,ctx); if (!ok) goto end; } - if (!X509_check_purpose(x, ctx->purpose, i)) + ret = X509_check_purpose(x, ctx->purpose, i); + if ((ret == 0) + || ((ctx->flags & X509_V_FLAG_X509_STRICT) + && (ret != 1))) { if (i) ctx->error = X509_V_ERR_INVALID_CA; @@ -537,6 +541,14 @@ static int check_crl(X509_STORE_CTX *ctx, X509_CRL *crl) if(issuer) { + /* Check for cRLSign bit if keyUsage present */ + if ((issuer->ex_flags & EXFLAG_KUSAGE) && + !(issuer->ex_kusage & KU_CRL_SIGN)) + { + ctx->error = X509_V_ERR_KEYUSAGE_NO_CRL_SIGN; + ok = ctx->verify_cb(0, ctx); + if(!ok) goto err; + } /* Attempt to get issuer certificate public key */ ikey = X509_get_pubkey(issuer); @@ -611,17 +623,46 @@ static int cert_crl(X509_STORE_CTX *ctx, X509_CRL *crl, X509 *x) { int idx, ok; X509_REVOKED rtmp; + STACK_OF(X509_EXTENSION) *exts; + X509_EXTENSION *ext; /* Look for serial number of certificate in CRL */ rtmp.serialNumber = X509_get_serialNumber(x); idx = sk_X509_REVOKED_find(crl->crl->revoked, &rtmp); - /* Not found: OK */ - if(idx == -1) return 1; - /* Otherwise revoked: want something cleverer than + /* If found assume revoked: want something cleverer than * this to handle entry extensions in V2 CRLs. */ - ctx->error = X509_V_ERR_CERT_REVOKED; - ok = ctx->verify_cb(0, ctx); - return ok; + if(idx >= 0) + { + ctx->error = X509_V_ERR_CERT_REVOKED; + ok = ctx->verify_cb(0, ctx); + if (!ok) return 0; + } + + if (ctx->flags & X509_V_FLAG_IGNORE_CRITICAL) + return 1; + + /* See if we have any critical CRL extensions: since we + * currently don't handle any CRL extensions the CRL must be + * rejected. + * This code accesses the X509_CRL structure directly: applications + * shouldn't do this. + */ + + exts = crl->crl->extensions; + + for (idx = 0; idx < sk_X509_EXTENSION_num(exts); idx++) + { + ext = sk_X509_EXTENSION_value(exts, idx); + if (ext->critical > 0) + { + ctx->error = + X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION; + ok = ctx->verify_cb(0, ctx); + if(!ok) return 0; + break; + } + } + return 1; } static int internal_verify(X509_STORE_CTX *ctx) diff --git a/crypto/x509/x509_vfy.h b/crypto/x509/x509_vfy.h index 3a0ccbe48d..7e24ded810 100644 --- a/crypto/x509/x509_vfy.h +++ b/crypto/x509/x509_vfy.h @@ -305,17 +305,26 @@ struct x509_store_ctx_st /* X509_STORE_CTX */ #define X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER 33 #define X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION 34 +#define X509_V_ERR_KEYUSAGE_NO_CRL_SIGN 35 +#define X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION 36 /* The application is not happy */ #define X509_V_ERR_APPLICATION_VERIFICATION 50 /* Certificate verify flags */ -#define X509_V_FLAG_CB_ISSUER_CHECK 0x1 /* Send issuer+subject checks to verify_cb */ -#define X509_V_FLAG_USE_CHECK_TIME 0x2 /* Use check time instead of current time */ -#define X509_V_FLAG_CRL_CHECK 0x4 /* Lookup CRLs */ -#define X509_V_FLAG_CRL_CHECK_ALL 0x8 /* Lookup CRLs for whole chain */ -#define X509_V_FLAG_IGNORE_CRITICAL 0x10 /* Ignore unhandled critical extensions */ +/* Send issuer+subject checks to verify_cb */ +#define X509_V_FLAG_CB_ISSUER_CHECK 0x1 +/* Use check time instead of current time */ +#define X509_V_FLAG_USE_CHECK_TIME 0x2 +/* Lookup CRLs */ +#define X509_V_FLAG_CRL_CHECK 0x4 +/* Lookup CRLs for whole chain */ +#define X509_V_FLAG_CRL_CHECK_ALL 0x8 +/* Ignore unhandled critical extensions */ +#define X509_V_FLAG_IGNORE_CRITICAL 0x10 +/* Disable workarounds for broken certificates */ +#define X509_V_FLAG_X509_STRICT 0x20 int X509_OBJECT_idx_by_subject(STACK_OF(X509_OBJECT) *h, int type, X509_NAME *name); diff --git a/crypto/x509v3/v3_purp.c b/crypto/x509v3/v3_purp.c index b1a6d2632a..67596862ab 100644 --- a/crypto/x509v3/v3_purp.c +++ b/crypto/x509v3/v3_purp.c @@ -3,7 +3,7 @@ * project 2001. */ /* ==================================================================== - * Copyright (c) 1999-2001 The OpenSSL Project. All rights reserved. + * Copyright (c) 1999-2004 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -415,6 +415,7 @@ static void x509v3_cache_extensions(X509 *x) * 1 is a CA * 2 basicConstraints absent so "maybe" a CA * 3 basicConstraints absent but self signed V1. + * 4 basicConstraints absent but keyUsage present and keyCertSign asserted. */ #define V1_ROOT (EXFLAG_V1|EXFLAG_SS) @@ -436,7 +437,7 @@ static int ca_check(const X509 *x) } else { if((x->ex_flags & V1_ROOT) == V1_ROOT) return 3; /* If key usage present it must have certSign so tolerate it */ - else if (x->ex_flags & EXFLAG_KUSAGE) return 3; + else if (x->ex_flags & EXFLAG_KUSAGE) return 4; else return 2; } } -- GitLab