Attribute certificate printing functions

Add functions to print an attribute certificate.  Several
attribute value types defined by the RFC 5755 specification
are multi-field values (i.e ASN1_SEQUENCE rather than an ASN1_STRING
or similar format).  Currently those values are printed using
`ASN1_item_print`.  A more user-friendly output mechanism (maybe
similar to the i2r_ functions used for X509 extensions) could be
added in future.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15857)

6 files changed, 410 insertions, 1 deletions

diff --git a/crypto/x509/build.info b/crypto/x509/build.info
index b580d2b4f8..873a9838b5 100644
--- a/crypto/x509/build.info
+++ b/crypto/x509/build.info
@@ -16,7 +16,7 @@ SOURCE[../../libcrypto]=\
         pcy_cache.c pcy_node.c pcy_data.c pcy_map.c pcy_tree.c pcy_lib.c \
         v3_asid.c v3_addr.c v3_tlsf.c v3_admis.c v3_no_rev_avail.c \
         v3_soa_id.c v3_no_ass.c v3_group_ac.c v3_single_use.c v3_ind_iss.c \
-        x509_acert.c x509aset.c
+        x509_acert.c x509aset.c t_acert.c
 
 IF[{- !$disabled{'deprecated-3.0'} -}]
   SOURCE[../../libcrypto]=x509type.c
diff --git a/crypto/x509/t_acert.c b/crypto/x509/t_acert.c
new file mode 100644
index 0000000000..0b5ab31311
--- /dev/null
+++ b/crypto/x509/t_acert.c
@@ -0,0 +1,285 @@
+/*
+ * Copyright 2021 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdio.h>
+#include "internal/cryptlib.h"
+#include <openssl/buffer.h>
+#include <openssl/bn.h>
+#include <openssl/objects.h>
+#include <openssl/x509_acert.h>
+
+static int print_attribute(BIO *bp, X509_ATTRIBUTE *a)
+{
+    ASN1_OBJECT *aobj;
+    int i, j, count;
+    int ret = 0;
+
+    aobj = X509_ATTRIBUTE_get0_object(a);
+    if (BIO_printf(bp, "%12s", "") <= 0)
+        goto err;
+
+    if ((j = i2a_ASN1_OBJECT(bp, aobj)) <= 0)
+        goto err;
+
+    count = X509_ATTRIBUTE_count(a);
+    if (count == 0) {
+        ERR_raise(ERR_LIB_X509, X509_R_INVALID_ATTRIBUTES);
+        goto err;
+    }
+
+    if (j < 25 && (BIO_printf(bp, "%*s", 25 - j, " ") <= 0))
+        goto err;
+
+    if (BIO_puts(bp, ":") <= 0)
+        goto err;
+
+    for (i = 0; i < count; i++) {
+        ASN1_TYPE *at;
+        int type;
+        ASN1_BIT_STRING *bs;
+
+        at = X509_ATTRIBUTE_get0_type(a, i);
+        type = at->type;
+
+        switch (type) {
+        case V_ASN1_PRINTABLESTRING:
+        case V_ASN1_T61STRING:
+        case V_ASN1_NUMERICSTRING:
+        case V_ASN1_UTF8STRING:
+        case V_ASN1_IA5STRING:
+            bs = at->value.asn1_string;
+            if (BIO_write(bp, (char *)bs->data, bs->length) != bs->length)
+                goto err;
+            if (BIO_puts(bp, "\n") <= 0)
+                goto err;
+            break;
+        case V_ASN1_SEQUENCE:
+            if (BIO_puts(bp, "\n") <= 0)
+                goto err;
+            ASN1_parse_dump(bp, at->value.sequence->data,
+                            at->value.sequence->length, i, 1);
+            break;
+        default:
+            if (BIO_printf(bp, "unable to print attribute of type 0x%X\n",
+                           type) < 0)
+                goto err;
+            break;
+        }
+    }
+    ret = 1;
+err:
+    return ret;
+}
+
+int X509_ACERT_print_ex(BIO *bp, X509_ACERT *x, unsigned long nmflags,
+                        unsigned long cflag)
+{
+    int i;
+    char mlch = ' ';
+
+    if ((nmflags & XN_FLAG_SEP_MASK) == XN_FLAG_SEP_MULTILINE) {
+        mlch = '\n';
+    }
+
+    if ((cflag & X509_FLAG_NO_HEADER) == 0) {
+        if (BIO_printf(bp, "Attribute Certificate:\n") <= 0)
+            goto err;
+        if (BIO_printf(bp, "%4sData:\n", "") <= 0)
+            goto err;
+    }
+
+    if ((cflag & X509_FLAG_NO_VERSION) == 0) {
+        long l;
+
+        l = X509_ACERT_get_version(x);
+        if (l == X509_ACERT_VERSION_2) {
+            if (BIO_printf(bp, "%8sVersion: %ld (0x%lx)\n", "", l + 1,
+                           (unsigned long)l) <= 0)
+                goto err;
+        } else {
+            if (BIO_printf(bp, "%8sVersion: Unknown (%ld)\n", "", l) <= 0)
+                goto err;
+        }
+    }
+
+    if ((cflag & X509_FLAG_NO_SERIAL) == 0) {
+        const ASN1_INTEGER *serial;
+
+        serial = X509_ACERT_get0_serialNumber(x);
+
+        if (BIO_printf(bp, "%8sSerial Number: ", "") <= 0)
+            goto err;
+
+        if (i2a_ASN1_INTEGER(bp, serial) <= 0)
+            goto err;
+
+        if (BIO_write(bp, "\n", 1) <= 0)
+            goto err;
+    }
+
+    if ((cflag & X509_FLAG_NO_SUBJECT) == 0) {
+        const GENERAL_NAMES *holderEntities;
+        const OSSL_ISSUER_SERIAL *holder_bcid;
+        const X509_NAME *holderIssuer = NULL;
+
+        if (BIO_printf(bp, "%8sHolder:\n", "") <= 0)
+            goto err;
+
+        holderEntities = X509_ACERT_get0_holder_entityName(x);
+        if (holderEntities != NULL) {
+            for (i = 0; i < sk_GENERAL_NAME_num(holderEntities); i++) {
+                GENERAL_NAME *entity;
+
+                entity = sk_GENERAL_NAME_value(holderEntities, i);
+
+                if (BIO_printf(bp, "%12sName:%c", "", mlch) <= 0)
+                    goto err;
+                if (GENERAL_NAME_print(bp, entity) <= 0)
+                    goto err;
+                if (BIO_write(bp, "\n", 1) <= 0)
+                    goto err;
+            }
+        }
+
+        if ((holder_bcid = X509_ACERT_get0_holder_baseCertId(x)) != NULL)
+            holderIssuer = OSSL_ISSUER_SERIAL_get0_issuer(holder_bcid);
+
+        if (holderIssuer != NULL) {
+            const ASN1_INTEGER *holder_serial;
+            const ASN1_BIT_STRING *iuid;
+
+            if (BIO_printf(bp, "%12sIssuer:%c", "", mlch) <= 0)
+                goto err;
+
+            if (X509_NAME_print_ex(bp, holderIssuer, 0, nmflags) <= 0)
+                goto err;
+
+            if (BIO_write(bp, "\n", 1) <= 0)
+                goto err;
+
+            if (BIO_printf(bp, "%12sSerial: ", "") <= 0)
+                goto err;
+
+            holder_serial = OSSL_ISSUER_SERIAL_get0_serial(holder_bcid);
+
+            if (i2a_ASN1_INTEGER(bp, holder_serial) <= 0)
+                goto err;
+
+            iuid = OSSL_ISSUER_SERIAL_get0_issuerUID(holder_bcid);
+            if (iuid != NULL) {
+                if (BIO_printf(bp, "%12sIssuer UID: ", "") <= 0)
+                    goto err;
+                if (X509_signature_dump(bp, iuid, 24) <= 0)
+                    goto err;
+            }
+            if (BIO_write(bp, "\n", 1) <= 0)
+                goto err;
+        }
+    }
+
+    if ((cflag & X509_FLAG_NO_ISSUER) == 0) {
+        const X509_NAME *issuer;
+
+        if (BIO_printf(bp, "%8sIssuer:%c", "", mlch) <= 0)
+            goto err;
+        issuer = X509_ACERT_get0_issuerName(x);
+        if (issuer) {
+            if (X509_NAME_print_ex(bp, issuer, 0, nmflags) < 0)
+                goto err;
+        } else {
+            if (BIO_printf(bp, "Unsupported Issuer Type") <= 0)
+                goto err;
+        }
+        if (BIO_write(bp, "\n", 1) <= 0)
+            goto err;
+    }
+
+    if ((cflag & X509_FLAG_NO_VALIDITY) == 0) {
+        if (BIO_printf(bp, "%8sValidity\n", "") <= 0)
+            goto err;
+        if (BIO_printf(bp, "%12sNot Before: ", "") <= 0)
+            goto err;
+        if (ASN1_GENERALIZEDTIME_print(bp, X509_ACERT_get0_notBefore(x)) == 0)
+            goto err;
+        if (BIO_printf(bp, "\n%12sNot After : ", "") <= 0)
+            goto err;
+        if (ASN1_GENERALIZEDTIME_print(bp, X509_ACERT_get0_notAfter(x)) == 0)
+            goto err;
+        if (BIO_write(bp, "\n", 1) <= 0)
+            goto err;
+    }
+
+    if ((cflag & X509_FLAG_NO_ATTRIBUTES) == 0) {
+        if (BIO_printf(bp, "%8sAttributes:\n", "") <= 0)
+            goto err;
+
+        if (X509_ACERT_get_attr_count(x) == 0) {
+            if (BIO_printf(bp, "%12s(none)\n", "") <= 0)
+                goto err;
+        } else {
+            for (i = 0; i < X509_ACERT_get_attr_count(x); i++) {
+                if (print_attribute(bp, X509_ACERT_get_attr(x, i)) == 0)
+                    goto err;
+            }
+        }
+    }
+
+    if ((cflag & X509_FLAG_NO_EXTENSIONS) == 0) {
+        const STACK_OF(X509_EXTENSION) *exts;
+
+        exts = X509_ACERT_get0_extensions(x);
+        if (exts != NULL) {
+            if (BIO_printf(bp, "%8sExtensions:\n", "") <= 0)
+                goto err;
+            for (i = 0; i < sk_X509_EXTENSION_num(exts); i++) {
+                ASN1_OBJECT *obj;
+                X509_EXTENSION *ex;
+                int critical;
+
+                ex = sk_X509_EXTENSION_value(exts, i);
+                if (BIO_printf(bp, "%12s", "") <= 0)
+                    goto err;
+                obj = X509_EXTENSION_get_object(ex);
+                if (i2a_ASN1_OBJECT(bp, obj) <= 0)
+                    goto err;
+                critical = X509_EXTENSION_get_critical(ex);
+                if (BIO_printf(bp, ": %s\n", critical ? "critical" : "") <= 0)
+                    goto err;
+                if (X509V3_EXT_print(bp, ex, cflag, 20) <= 0) {
+                    if (BIO_printf(bp, "%16s", "") <= 0)
+                        goto err;
+                    if (ASN1_STRING_print(bp, X509_EXTENSION_get_data(ex)) <= 0)
+                        goto err;
+                }
+                if (BIO_write(bp, "\n", 1) <= 0)
+                    goto err;
+            }
+        }
+    }
+
+    if ((cflag & X509_FLAG_NO_SIGDUMP) == 0) {
+        const X509_ALGOR *sig_alg;
+        const ASN1_BIT_STRING *sig;
+
+        X509_ACERT_get0_signature(x, &sig, &sig_alg);
+        if (X509_signature_print(bp, sig_alg, sig) <= 0)
+            return 0;
+    }
+
+    return 1;
+
+err:
+    ERR_raise(ERR_LIB_X509, ERR_R_BUF_LIB);
+    return 0;
+}
+
+int X509_ACERT_print(BIO *bp, X509_ACERT *x)
+{
+    return X509_ACERT_print_ex(bp, x, XN_FLAG_COMPAT, X509_FLAG_COMPAT);
+}
diff --git a/doc/build.info b/doc/build.info
index da0e7a637f..43bb3c8a1d 100644
--- a/doc/build.info
+++ b/doc/build.info
@@ -2803,6 +2803,10 @@ DEPEND[html/man3/X509_ACERT_get0_holder_baseCertId.html]=man3/X509_ACERT_get0_ho
 GENERATE[html/man3/X509_ACERT_get0_holder_baseCertId.html]=man3/X509_ACERT_get0_holder_baseCertId.pod
 DEPEND[man/man3/X509_ACERT_get0_holder_baseCertId.3]=man3/X509_ACERT_get0_holder_baseCertId.pod
 GENERATE[man/man3/X509_ACERT_get0_holder_baseCertId.3]=man3/X509_ACERT_get0_holder_baseCertId.pod
+DEPEND[html/man3/X509_ACERT_print_ex.html]=man3/X509_ACERT_print_ex.pod
+GENERATE[html/man3/X509_ACERT_print_ex.html]=man3/X509_ACERT_print_ex.pod
+DEPEND[man/man3/X509_ACERT_print_ex.3]=man3/X509_ACERT_print_ex.pod
+GENERATE[man/man3/X509_ACERT_print_ex.3]=man3/X509_ACERT_print_ex.pod
 DEPEND[html/man3/X509_ALGOR_dup.html]=man3/X509_ALGOR_dup.pod
 GENERATE[html/man3/X509_ALGOR_dup.html]=man3/X509_ALGOR_dup.pod
 DEPEND[man/man3/X509_ALGOR_dup.3]=man3/X509_ALGOR_dup.pod
@@ -3636,6 +3640,7 @@ html/man3/UI_new.html \
 html/man3/X509V3_get_d2i.html \
 html/man3/X509V3_set_ctx.html \
 html/man3/X509_ACERT_get0_holder_baseCertId.html \
+html/man3/X509_ACERT_print_ex.html \
 html/man3/X509_ALGOR_dup.html \
 html/man3/X509_ATTRIBUTE.html \
 html/man3/X509_CRL_get0_by_serial.html \
@@ -4282,6 +4287,7 @@ man/man3/UI_new.3 \
 man/man3/X509V3_get_d2i.3 \
 man/man3/X509V3_set_ctx.3 \
 man/man3/X509_ACERT_get0_holder_baseCertId.3 \
+man/man3/X509_ACERT_print_ex.3 \
 man/man3/X509_ALGOR_dup.3 \
 man/man3/X509_ATTRIBUTE.3 \
 man/man3/X509_CRL_get0_by_serial.3 \
diff --git a/doc/man3/X509_ACERT_print_ex.pod b/doc/man3/X509_ACERT_print_ex.pod
new file mode 100644
index 0000000000..3a5e0c7a51
--- /dev/null
+++ b/doc/man3/X509_ACERT_print_ex.pod
@@ -0,0 +1,112 @@
+=pod
+
+=head1 NAME
+
+X509_ACERT_print_ex, X509_ACERT_print
+- X509_ACERT printing routines
+
+=head1 SYNOPSIS
+
+ #include <openssl/x509_acert.h>
+
+ int X509_ACERT_print(BIO *bp, X509_ACERT *acert);
+ int X509_ACERT_print_ex(BIO *bp, X509_ACERT *acert, unsigned long nmflags,
+                         unsigned long cflag);
+
+=head1 DESCRIPTION
+
+X509_ACERT_print_ex() prints a human readable version of the attribute
+certificate I<acert> to BIO I<bp>.
+
+The following data contained in the attribute certificate is printed
+in order:
+
+=over 4
+
+=item *
+
+The header text "Attribute certificate:" and "Data:" (X509_FLAG_NO_HEADER)
+
+= item *
+
+The attribute certificate version number as defined by the standard,
+followed in parentheses by the value contained in the version field in
+hexadecimal notation.  If the version number is not a valid value according
+to the specification, only the raw value is printed.
+See X509_ACERT_get_version(3) for details. (X509_FLAG_NO_VERSION)
+
+= item *
+
+The serial number of the attribute certificate (X509_FLAG_NO_SERIAL)
+
+= item *
+
+The identity of the holder of the attribute certificate. If the
+holder issuer name is present, the first GENERAL_NAME
+returned by X509_ACERT_get0_holder_entityName() is printed.
+If the holder baseCertificateId is present, the issuer name
+(printed with X509_NAME_print_ex) and serial number of the
+holder's certificate are displayed. (X509_FLAG_NO_SUBJECT)
+
+= item *
+
+The name of the attribute certificate issuer as returned from
+X509_ACERT_get0_issuerName() and printed using X509_NAME_print_ex().
+(X509_FLAG_NO_ISSUER)
+
+= item *
+
+The period of validity between the times returned from X509_ACERT_get0_notBefore()
+and  X509_ACERT_get0_notAfter().  The values are printed as a generalized times
+using ASN1_GENERALIZEDTIME_print(). (X509_FLAG_NO_VALIDITY)
+
+= item *
+
+The list of attributes contained in the attribute certificate.
+The attribute type is printed with i2a_ASN1_OBJECT().  String valued
+attributes are printed as raw string data. ASN1 encoded values are
+printed with ASN1_parse_dump().  (X509_FLAG_NO_ATTRIBUTES)
+
+= item *
+
+All X.509 extensions contained in the attribute certificate. (X509_FLAG_NO_EXTENSIONS)
+
+= item *
+
+The signature is printed with X509_signature_print(). (X509_FLAG_NO_SIGDUMP)
+
+If I<cflag> is specifies as X509_FLAG_COMPAT, all of the above data in the
+attribute certificate will be printed.
+
+The I<nmflags> flag determines the format used to output all fields printed using
+X509_NAME_print_ex(). See L<X509_NAME_print_ex(3)> for details.
+
+X509_ACERT_print() is equivalent to calling X509_ACERT_print_ex() with the
+I<nmflags> and I<cflags> set to XN_FLAG_COMPAT and X509_FLAG_COMPAT
+respectively.
+
+=back
+
+=head1 RETURN VALUES
+
+X509_ACERT_print_ex() X509_ACERT_print() return 1 for
+success and 0 for failure.
+
+=head1 SEE ALSO
+
+L<X509_NAME_print_ex(3)>
+
+=head1 HISTORY
+
+X509_ACERT_print() and X509_ACERT_print_ex() were added in OpenSSL 3.4.
+
+=head1 COPYRIGHT
+
+Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the Apache License 2.0 (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut
diff --git a/include/openssl/x509_acert.h.in b/include/openssl/x509_acert.h.in
index 826f39d423..867eab7869 100644
--- a/include/openssl/x509_acert.h.in
+++ b/include/openssl/x509_acert.h.in
@@ -62,6 +62,10 @@ const ASN1_TIME *X509_ACERT_get0_notBefore(const X509_ACERT *x);
 const ASN1_TIME *X509_ACERT_get0_notAfter(const X509_ACERT *x);
 const ASN1_BIT_STRING *X509_ACERT_get0_issuerUID(const X509_ACERT *x);
 
+int X509_ACERT_print(BIO *bp, X509_ACERT *x);
+int X509_ACERT_print_ex(BIO *bp, X509_ACERT *x, unsigned long nmflags,
+                        unsigned long cflag);
+
 # define OSSL_OBJECT_DIGEST_INFO_PUBLIC_KEY        0
 # define OSSL_OBJECT_DIGEST_INFO_PUBLIC_KEY_CERT   1
 # define OSSL_OBJECT_DIGEST_INFO_OTHER             2  /* must not be used in RFC 5755 profile */
diff --git a/util/libcrypto.num b/util/libcrypto.num
index 57dee34ec0..222c10ef95 100644
--- a/util/libcrypto.num
+++ b/util/libcrypto.num
@@ -5601,3 +5601,5 @@ OSSL_ISSUER_SERIAL_get0_issuerUID       ?	3_4_0	EXIST::FUNCTION:
 OSSL_ISSUER_SERIAL_set1_issuer          ?	3_4_0	EXIST::FUNCTION:
 OSSL_ISSUER_SERIAL_set1_serial          ?	3_4_0	EXIST::FUNCTION:
 OSSL_ISSUER_SERIAL_set1_issuerUID       ?	3_4_0	EXIST::FUNCTION:
+X509_ACERT_print                        ?	3_4_0	EXIST::FUNCTION:
+X509_ACERT_print_ex                     ?	3_4_0	EXIST::FUNCTION: