x509_att.c: improve error checking and reporting and coding style

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
(Merged from https://github.com/openssl/openssl/pull/18931)

7 files changed, 76 insertions, 57 deletions

diff --git a/crypto/err/openssl.txt b/crypto/err/openssl.txt
index 3f1d844e04..e6db85e96c 100644
--- a/crypto/err/openssl.txt
+++ b/crypto/err/openssl.txt
@@ -1691,6 +1691,7 @@ X509_R_CERTIFICATE_VERIFICATION_FAILED:139:certificate verification failed
 X509_R_CERT_ALREADY_IN_HASH_TABLE:101:cert already in hash table
 X509_R_CRL_ALREADY_DELTA:127:crl already delta
 X509_R_CRL_VERIFY_FAILURE:131:crl verify failure
+X509_R_DUPLICATE_ATTRIBUTE:140:duplicate attribute
 X509_R_ERROR_GETTING_MD_BY_NID:141:error getting md by nid
 X509_R_ERROR_USING_SIGINF_SET:142:error using siginf set
 X509_R_IDP_MISMATCH:128:idp mismatch
diff --git a/crypto/pkcs12/p12_attr.c b/crypto/pkcs12/p12_attr.c
index da228336eb..568a32a55e 100644
--- a/crypto/pkcs12/p12_attr.c
+++ b/crypto/pkcs12/p12_attr.c
@@ -95,11 +95,11 @@ int PKCS12_add1_attr_by_txt(PKCS12_SAFEBAG *bag, const char *attrname, int type,
 ASN1_TYPE *PKCS12_get_attr_gen(const STACK_OF(X509_ATTRIBUTE) *attrs,
                                int attr_nid)
 {
-    X509_ATTRIBUTE *attrib;
-    int i;
-    i = X509at_get_attr_by_NID(attrs, attr_nid, -1);
-    attrib = X509at_get_attr(attrs, i);
-    return X509_ATTRIBUTE_get0_type(attrib, 0);
+    int i = X509at_get_attr_by_NID(attrs, attr_nid, -1);
+
+    if (i < 0)
+        return NULL;
+    return X509_ATTRIBUTE_get0_type(X509at_get_attr(attrs, i), 0);
 }
 
 char *PKCS12_get_friendlyname(PKCS12_SAFEBAG *bag)
diff --git a/crypto/pkcs12/p12_crt.c b/crypto/pkcs12/p12_crt.c
index 00c7129746..7889842b6f 100644
--- a/crypto/pkcs12/p12_crt.c
+++ b/crypto/pkcs12/p12_crt.c
@@ -17,15 +17,11 @@ static int pkcs12_add_bag(STACK_OF(PKCS12_SAFEBAG) **pbags,
 
 static int copy_bag_attr(PKCS12_SAFEBAG *bag, EVP_PKEY *pkey, int nid)
 {
-    int idx;
-    X509_ATTRIBUTE *attr;
-    idx = EVP_PKEY_get_attr_by_NID(pkey, nid, -1);
+    int idx = EVP_PKEY_get_attr_by_NID(pkey, nid, -1);
+
     if (idx < 0)
         return 1;
-    attr = EVP_PKEY_get_attr(pkey, idx);
-    if (!X509at_add1_attr(&bag->attrib, attr))
-        return 0;
-    return 1;
+    return X509at_add1_attr(&bag->attrib, EVP_PKEY_get_attr(pkey, idx)) != NULL;
 }
 
 PKCS12 *PKCS12_create_ex(const char *pass, const char *name, EVP_PKEY *pkey,
diff --git a/crypto/pkcs7/pk7_doit.c b/crypto/pkcs7/pk7_doit.c
index 4a13070a0a..e68aaca466 100644
--- a/crypto/pkcs7/pk7_doit.c
+++ b/crypto/pkcs7/pk7_doit.c
@@ -1162,11 +1162,11 @@ ASN1_TYPE *PKCS7_get_attribute(const PKCS7_SIGNER_INFO *si, int nid)
 
 static ASN1_TYPE *get_attribute(const STACK_OF(X509_ATTRIBUTE) *sk, int nid)
 {
-    int idx;
-    X509_ATTRIBUTE *xa;
-    idx = X509at_get_attr_by_NID(sk, nid, -1);
-    xa = X509at_get_attr(sk, idx);
-    return X509_ATTRIBUTE_get0_type(xa, 0);
+    int idx = X509at_get_attr_by_NID(sk, nid, -1);
+
+    if (idx < 0)
+        return NULL;
+    return X509_ATTRIBUTE_get0_type(X509at_get_attr(sk, idx), 0);
 }
 
 ASN1_OCTET_STRING *PKCS7_digest_from_attributes(STACK_OF(X509_ATTRIBUTE) *sk)
diff --git a/crypto/x509/x509_att.c b/crypto/x509/x509_att.c
index 73ac59454d..9e6434187c 100644
--- a/crypto/x509/x509_att.c
+++ b/crypto/x509/x509_att.c
@@ -55,20 +55,28 @@ int X509at_get_attr_by_OBJ(const STACK_OF(X509_ATTRIBUTE) *sk,
 
 X509_ATTRIBUTE *X509at_get_attr(const STACK_OF(X509_ATTRIBUTE) *x, int loc)
 {
-    if (x == NULL || sk_X509_ATTRIBUTE_num(x) <= loc || loc < 0)
+    if (x == NULL) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_NULL_PARAMETER);
         return NULL;
-
+    }
+    if (sk_X509_ATTRIBUTE_num(x) <= loc || loc < 0) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_INVALID_ARGUMENT);
+        return NULL;
+    }
     return sk_X509_ATTRIBUTE_value(x, loc);
 }
 
 X509_ATTRIBUTE *X509at_delete_attr(STACK_OF(X509_ATTRIBUTE) *x, int loc)
 {
-    X509_ATTRIBUTE *ret;
-
-    if (x == NULL || sk_X509_ATTRIBUTE_num(x) <= loc || loc < 0)
+    if (x == NULL) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_NULL_PARAMETER);
         return NULL;
-    ret = sk_X509_ATTRIBUTE_delete(x, loc);
-    return ret;
+    }
+    if (sk_X509_ATTRIBUTE_num(x) <= loc || loc < 0) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_INVALID_ARGUMENT);
+        return NULL;
+    }
+    return sk_X509_ATTRIBUTE_delete(x, loc);
 }
 
 STACK_OF(X509_ATTRIBUTE) *X509at_add1_attr(STACK_OF(X509_ATTRIBUTE) **x,
@@ -77,10 +85,14 @@ STACK_OF(X509_ATTRIBUTE) *X509at_add1_attr(STACK_OF(X509_ATTRIBUTE) **x,
     X509_ATTRIBUTE *new_attr = NULL;
     STACK_OF(X509_ATTRIBUTE) *sk = NULL;
 
-    if (x == NULL) {
+    if (x == NULL || attr == NULL) {
         ERR_raise(ERR_LIB_X509, ERR_R_PASSED_NULL_PARAMETER);
         return NULL;
     }
+    if (X509at_get_attr_by_OBJ(sk, attr->object, -1) != -1) {
+        ERR_raise(ERR_LIB_X509, X509_R_DUPLICATE_ATTRIBUTE);
+        return NULL;
+    }
 
     if (*x == NULL) {
         if ((sk = sk_X509_ATTRIBUTE_new_null()) == NULL)
@@ -113,8 +125,9 @@ STACK_OF(X509_ATTRIBUTE) *X509at_add1_attr_by_OBJ(STACK_OF(X509_ATTRIBUTE)
 {
     X509_ATTRIBUTE *attr;
     STACK_OF(X509_ATTRIBUTE) *ret;
+
     attr = X509_ATTRIBUTE_create_by_OBJ(NULL, obj, type, bytes, len);
-    if (!attr)
+    if (attr == NULL)
         return 0;
     ret = X509at_add1_attr(x, attr);
     X509_ATTRIBUTE_free(attr);
@@ -128,8 +141,9 @@ STACK_OF(X509_ATTRIBUTE) *X509at_add1_attr_by_NID(STACK_OF(X509_ATTRIBUTE)
 {
     X509_ATTRIBUTE *attr;
     STACK_OF(X509_ATTRIBUTE) *ret;
+
     attr = X509_ATTRIBUTE_create_by_NID(NULL, nid, type, bytes, len);
-    if (!attr)
+    if (attr == NULL)
         return 0;
     ret = X509at_add1_attr(x, attr);
     X509_ATTRIBUTE_free(attr);
@@ -144,8 +158,9 @@ STACK_OF(X509_ATTRIBUTE) *X509at_add1_attr_by_txt(STACK_OF(X509_ATTRIBUTE)
 {
     X509_ATTRIBUTE *attr;
     STACK_OF(X509_ATTRIBUTE) *ret;
+
     attr = X509_ATTRIBUTE_create_by_txt(NULL, attrname, type, bytes, len);
-    if (!attr)
+    if (attr == NULL)
         return 0;
     ret = X509at_add1_attr(x, attr);
     X509_ATTRIBUTE_free(attr);
@@ -155,29 +170,26 @@ STACK_OF(X509_ATTRIBUTE) *X509at_add1_attr_by_txt(STACK_OF(X509_ATTRIBUTE)
 void *X509at_get0_data_by_OBJ(const STACK_OF(X509_ATTRIBUTE) *x,
                               const ASN1_OBJECT *obj, int lastpos, int type)
 {
-    int i;
+    int i = X509at_get_attr_by_OBJ(x, obj, lastpos);
     X509_ATTRIBUTE *at;
-    i = X509at_get_attr_by_OBJ(x, obj, lastpos);
+
     if (i == -1)
         return NULL;
-    if ((lastpos <= -2) && (X509at_get_attr_by_OBJ(x, obj, i) != -1))
+    if (lastpos <= -2 && X509at_get_attr_by_OBJ(x, obj, i) != -1)
         return NULL;
     at = X509at_get_attr(x, i);
-    if (lastpos <= -3 && (X509_ATTRIBUTE_count(at) != 1))
+    if (lastpos <= -3 && X509_ATTRIBUTE_count(at) != 1)
         return NULL;
     return X509_ATTRIBUTE_get0_data(at, 0, type, NULL);
 }
 
 STACK_OF(X509_ATTRIBUTE) *ossl_x509at_dup(const STACK_OF(X509_ATTRIBUTE) *x)
 {
-    int i, n;
+    int i, n = sk_X509_ATTRIBUTE_num(x);
     STACK_OF(X509_ATTRIBUTE) *sk = NULL;
 
-    n = sk_X509_ATTRIBUTE_num(x);
     for (i = 0; i < n; ++i) {
-        X509_ATTRIBUTE *attr = sk_X509_ATTRIBUTE_value(x, i);
-
-        if (X509at_add1_attr(&sk, attr) == NULL) {
+        if (X509at_add1_attr(&sk, sk_X509_ATTRIBUTE_value(x, i)) == NULL) {
             sk_X509_ATTRIBUTE_pop_free(sk, X509_ATTRIBUTE_free);
             return NULL;
         }
@@ -189,10 +201,9 @@ X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_NID(X509_ATTRIBUTE **attr, int nid,
                                              int atrtype, const void *data,
                                              int len)
 {
-    ASN1_OBJECT *obj;
+    ASN1_OBJECT *obj = OBJ_nid2obj(nid);
     X509_ATTRIBUTE *ret;
 
-    obj = OBJ_nid2obj(nid);
     if (obj == NULL) {
         ERR_raise(ERR_LIB_X509, X509_R_UNKNOWN_NID);
         return NULL;
@@ -210,24 +221,25 @@ X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_OBJ(X509_ATTRIBUTE **attr,
 {
     X509_ATTRIBUTE *ret;
 
-    if ((attr == NULL) || (*attr == NULL)) {
+    if (attr == NULL || *attr == NULL) {
         if ((ret = X509_ATTRIBUTE_new()) == NULL) {
             ERR_raise(ERR_LIB_X509, ERR_R_MALLOC_FAILURE);
             return NULL;
         }
-    } else
+    } else {
         ret = *attr;
+    }
 
     if (!X509_ATTRIBUTE_set1_object(ret, obj))
         goto err;
     if (!X509_ATTRIBUTE_set1_data(ret, atrtype, data, len))
         goto err;
 
-    if ((attr != NULL) && (*attr == NULL))
+    if (attr != NULL && *attr == NULL)
         *attr = ret;
     return ret;
  err:
-    if ((attr == NULL) || (ret != *attr))
+    if (attr == NULL || ret != *attr)
         X509_ATTRIBUTE_free(ret);
     return NULL;
 }
@@ -237,10 +249,9 @@ X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_txt(X509_ATTRIBUTE **attr,
                                              const unsigned char *bytes,
                                              int len)
 {
-    ASN1_OBJECT *obj;
+    ASN1_OBJECT *obj = OBJ_txt2obj(atrname, 0);
     X509_ATTRIBUTE *nattr;
 
-    obj = OBJ_txt2obj(atrname, 0);
     if (obj == NULL) {
         ERR_raise_data(ERR_LIB_X509, X509_R_INVALID_FIELD_NAME,
                        "name=%s", atrname);
@@ -253,8 +264,10 @@ X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_txt(X509_ATTRIBUTE **attr,
 
 int X509_ATTRIBUTE_set1_object(X509_ATTRIBUTE *attr, const ASN1_OBJECT *obj)
 {
-    if ((attr == NULL) || (obj == NULL))
+    if (attr == NULL || obj == NULL) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_NULL_PARAMETER);
         return 0;
+    }
     ASN1_OBJECT_free(attr->object);
     attr->object = OBJ_dup(obj);
     return attr->object != NULL;
@@ -266,12 +279,15 @@ int X509_ATTRIBUTE_set1_data(X509_ATTRIBUTE *attr, int attrtype,
     ASN1_TYPE *ttmp = NULL;
     ASN1_STRING *stmp = NULL;
     int atype = 0;
-    if (!attr)
+
+    if (attr == NULL) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_NULL_PARAMETER);
         return 0;
-    if (attrtype & MBSTRING_FLAG) {
+    }
+    if ((attrtype & MBSTRING_FLAG) != 0) {
         stmp = ASN1_STRING_set_by_NID(NULL, data, len, attrtype,
                                       OBJ_obj2nid(attr->object));
-        if (!stmp) {
+        if (stmp == NULL) {
             ERR_raise(ERR_LIB_X509, ERR_R_ASN1_LIB);
             return 0;
         }
@@ -294,7 +310,7 @@ int X509_ATTRIBUTE_set1_data(X509_ATTRIBUTE *attr, int attrtype,
     }
     if ((ttmp = ASN1_TYPE_new()) == NULL)
         goto err;
-    if ((len == -1) && !(attrtype & MBSTRING_FLAG)) {
+    if (len == -1 && (attrtype & MBSTRING_FLAG) == 0) {
         if (!ASN1_TYPE_set1(ttmp, attrtype, data))
             goto err;
     } else {
@@ -320,17 +336,19 @@ int X509_ATTRIBUTE_count(const X509_ATTRIBUTE *attr)
 
 ASN1_OBJECT *X509_ATTRIBUTE_get0_object(X509_ATTRIBUTE *attr)
 {
-    if (attr == NULL)
+    if (attr == NULL) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_NULL_PARAMETER);
         return NULL;
+    }
     return attr->object;
 }
 
 void *X509_ATTRIBUTE_get0_data(X509_ATTRIBUTE *attr, int idx,
                                int atrtype, void *data)
 {
-    ASN1_TYPE *ttmp;
-    ttmp = X509_ATTRIBUTE_get0_type(attr, idx);
-    if (!ttmp)
+    ASN1_TYPE *ttmp = X509_ATTRIBUTE_get0_type(attr, idx);
+
+    if (ttmp == NULL)
         return NULL;
     if (atrtype == V_ASN1_BOOLEAN
             || atrtype == V_ASN1_NULL
@@ -343,7 +361,9 @@ void *X509_ATTRIBUTE_get0_data(X509_ATTRIBUTE *attr, int idx,
 
 ASN1_TYPE *X509_ATTRIBUTE_get0_type(X509_ATTRIBUTE *attr, int idx)
 {
-    if (attr == NULL)
+    if (attr == NULL) {
+        ERR_raise(ERR_LIB_X509, ERR_R_PASSED_NULL_PARAMETER);
         return NULL;
+    }
     return sk_ASN1_TYPE_value(attr->set, idx);
 }
diff --git a/crypto/x509/x509_err.c b/crypto/x509/x509_err.c
index a933aeef35..61f1e3ecc1 100644
--- a/crypto/x509/x509_err.c
+++ b/crypto/x509/x509_err.c
@@ -1,6 +1,6 @@
 /*
  * Generated by util/mkerr.pl DO NOT EDIT
- * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2022 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
@@ -28,6 +28,8 @@ static const ERR_STRING_DATA X509_str_reasons[] = {
     {ERR_PACK(ERR_LIB_X509, 0, X509_R_CRL_ALREADY_DELTA), "crl already delta"},
     {ERR_PACK(ERR_LIB_X509, 0, X509_R_CRL_VERIFY_FAILURE),
     "crl verify failure"},
+    {ERR_PACK(ERR_LIB_X509, 0, X509_R_DUPLICATE_ATTRIBUTE),
+    "duplicate attribute"},
     {ERR_PACK(ERR_LIB_X509, 0, X509_R_ERROR_GETTING_MD_BY_NID),
     "error getting md by nid"},
     {ERR_PACK(ERR_LIB_X509, 0, X509_R_ERROR_USING_SIGINF_SET),
diff --git a/crypto/x509/x509_req.c b/crypto/x509/x509_req.c
index 9e926fbe29..858c6c566c 100644
--- a/crypto/x509/x509_req.c
+++ b/crypto/x509/x509_req.c
@@ -146,7 +146,7 @@ STACK_OF(X509_EXTENSION) *X509_REQ_get_extensions(X509_REQ *req)
         return NULL;
     for (pnid = ext_nids; *pnid != NID_undef; pnid++) {
         idx = X509_REQ_get_attr_by_NID(req, *pnid, -1);
-        if (idx == -1)
+        if (idx < 0)
             continue;
         attr = X509_REQ_get_attr(req, idx);
         ext = X509_ATTRIBUTE_get0_type(attr, 0);