APPS: Allow OPENSSL_CONF to be empty, not loading a config file

Also document the function CONF_get1_default_config_file()

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/13658)

14 files changed, 67 insertions, 76 deletions

diff --git a/apps/ca.c b/apps/ca.c
index f580d97e2d..d97be7568e 100755
--- a/apps/ca.c
+++ b/apps/ca.c
@@ -494,9 +494,7 @@ end_of_options:
     argc = opt_num_rest();
     argv = opt_rest();
 
-    BIO_printf(bio_err, "Using configuration from %s\n", configfile);
-
-    if ((conf = app_load_config(configfile)) == NULL)
+    if ((conf = app_load_config_verbose(configfile, 1)) == NULL)
         goto end;
     if (configfile != default_config_file && !app_load_modules(conf))
         goto end;
diff --git a/apps/include/apps.h b/apps/include/apps.h
index 30dc5d85f7..4bed7d7540 100644
--- a/apps/include/apps.h
+++ b/apps/include/apps.h
@@ -48,7 +48,7 @@
 void app_RAND_load_conf(CONF *c, const char *section);
 void app_RAND_write(void);
 
-extern char *default_config_file;
+extern char *default_config_file; /* may be "" */
 extern BIO *bio_in;
 extern BIO *bio_out;
 extern BIO *bio_err;
@@ -63,8 +63,10 @@ BIO *bio_open_owner(const char *filename, int format, int private);
 BIO *bio_open_default(const char *filename, char mode, int format);
 BIO *bio_open_default_quiet(const char *filename, char mode, int format);
 CONF *app_load_config_bio(BIO *in, const char *filename);
-CONF *app_load_config(const char *filename);
-CONF *app_load_config_quiet(const char *filename);
+#define app_load_config(filename) app_load_config_internal(filename, 0)
+#define app_load_config_quiet(filename) app_load_config_internal(filename, 1)
+CONF *app_load_config_internal(const char *filename, int quiet);
+CONF *app_load_config_verbose(const char *filename, int verbose);
 int app_load_modules(const CONF *config);
 CONF *app_load_config_modules(const char *configfile);
 void unbuffer(FILE *fp);
diff --git a/apps/lib/apps.c b/apps/lib/apps.c
index 6ae35bac73..d5654d9dc9 100644
--- a/apps/lib/apps.c
+++ b/apps/lib/apps.c
@@ -54,6 +54,9 @@ static int WIN32_rename(const char *from, const char *to);
 # define _kbhit kbhit
 #endif
 
+static BIO *bio_open_default_(const char *filename, char mode, int format,
+                              int quiet);
+
 #define PASS_SOURCE_SIZE_MAX 4
 
 DEFINE_STACK_OF(CONF)
@@ -379,29 +382,25 @@ CONF *app_load_config_bio(BIO *in, const char *filename)
     return NULL;
 }
 
-CONF *app_load_config(const char *filename)
+CONF *app_load_config_verbose(const char *filename, int verbose)
 {
-    BIO *in;
-    CONF *conf;
-
-    in = bio_open_default(filename, 'r', FORMAT_TEXT);
-    if (in == NULL)
-        return NULL;
-
-    conf = app_load_config_bio(in, filename);
-    BIO_free(in);
-    return conf;
+    if (verbose) {
+        if (*filename == '\0')
+            BIO_printf(bio_err, "No configuration used\n");
+        else
+            BIO_printf(bio_err, "Using configuration from %s\n", filename);
+    }
+    return app_load_config_internal(filename, 0);
 }
 
-CONF *app_load_config_quiet(const char *filename)
+CONF *app_load_config_internal(const char *filename, int quiet)
 {
-    BIO *in;
+    BIO *in = NULL; /* leads to empty config in case filename == "" */
     CONF *conf;
 
-    in = bio_open_default_quiet(filename, 'r', FORMAT_TEXT);
-    if (in == NULL)
+    if (*filename != '\0'
+        && (in = bio_open_default_(filename, 'r', FORMAT_TEXT, quiet)) == NULL)
         return NULL;
-
     conf = app_load_config_bio(in, filename);
     BIO_free(in);
     return conf;
@@ -457,9 +456,7 @@ CONF *app_load_config_modules(const char *configfile)
     CONF *conf = NULL;
 
     if (configfile != NULL) {
-        BIO_printf(bio_err, "Using configuration from %s\n", configfile);
-
-        if ((conf = app_load_config(configfile)) == NULL)
+        if ((conf = app_load_config_verbose(configfile, 1)) == NULL)
             return NULL;
         if (configfile != default_config_file && !app_load_modules(conf)) {
             NCONF_free(conf);
@@ -2789,7 +2786,7 @@ static BIO *bio_open_default_(const char *filename, char mode, int format,
         if (ret != NULL)
             return ret;
         BIO_printf(bio_err,
-                   "Can't open %s for %s, %s\n",
+                   "Can't open \"%s\" for %s, %s\n",
                    filename, modeverb(mode), strerror(errno));
     }
     ERR_print_errors(bio_err);
diff --git a/apps/req.c b/apps/req.c
index 5a065ad843..b645cc1039 100644
--- a/apps/req.c
+++ b/apps/req.c
@@ -466,9 +466,7 @@ int req_main(int argc, char **argv)
         goto end;
     }
 
-    if (verbose)
-        BIO_printf(bio_err, "Using configuration from %s\n", template);
-    if ((req_conf = app_load_config(template)) == NULL)
+    if ((req_conf = app_load_config_verbose(template, verbose)) == NULL)
         goto end;
     if (addext_bio != NULL) {
         if (verbose)
@@ -635,7 +633,7 @@ int req_main(int argc, char **argv)
         if (genctx == NULL) {
             genctx = set_keygen_ctx(NULL, &pkey_type, &newkey,
                                     &keyalgstr, gen_eng);
-            if (!genctx)
+            if (genctx == NULL)
                 goto end;
         }
 
@@ -645,7 +643,6 @@ int req_main(int argc, char **argv)
                 genopt = sk_OPENSSL_STRING_value(pkeyopts, i);
                 if (pkey_ctrl_string(genctx, genopt) <= 0) {
                     BIO_printf(bio_err, "parameter error \"%s\"\n", genopt);
-                    ERR_print_errors(bio_err);
                     goto end;
                 }
             }
@@ -743,7 +740,6 @@ int req_main(int argc, char **argv)
             if ((x509ss = X509_new_ex(app_get0_libctx(), app_get0_propq())) == NULL)
                 goto end;
 
-            /* Set version to V3 */
             if (serial != NULL) {
                 if (!X509_set_serialNumber(x509ss, serial))
                     goto end;
@@ -768,7 +764,6 @@ int req_main(int argc, char **argv)
                 goto end;
 
             /* Set up V3 context struct */
-
             X509V3_set_ctx(&ext_ctx, x509ss, x509ss, NULL, NULL, X509V3_CTX_REPLACE);
             X509V3_set_nconf(&ext_ctx, req_conf);
 
@@ -797,10 +792,8 @@ int req_main(int argc, char **argv)
             }
 
             i = do_X509_sign(x509ss, pkey, digest, sigopts, &ext_ctx);
-            if (!i) {
-                ERR_print_errors(bio_err);
+            if (!i)
                 goto end;
-            }
         } else {
             X509V3_CTX ext_ctx;
 
@@ -824,10 +817,8 @@ int req_main(int argc, char **argv)
                 goto end;
             }
             i = do_X509_REQ_sign(req, pkey, digest, sigopts);
-            if (!i) {
-                ERR_print_errors(bio_err);
+            if (!i)
                 goto end;
-            }
         }
     }
 
@@ -893,7 +884,6 @@ int req_main(int argc, char **argv)
 
         if (tpubkey == NULL) {
             BIO_printf(bio_err, "Error getting public key\n");
-            ERR_print_errors(bio_err);
             goto end;
         }
         PEM_write_bio_PUBKEY(out, tpubkey);
@@ -911,7 +901,6 @@ int req_main(int argc, char **argv)
             else
               BIO_printf(bio_err, "Error printing certificate request\n");
 
-            ERR_print_errors(bio_err);
             goto end;
         }
     }
@@ -1008,7 +997,7 @@ static int make_REQ(X509_REQ *req, EVP_PKEY *pkey, char *subj, int multirdn,
 {
     int ret = 0, i;
     char no_prompt = 0;
-    STACK_OF(CONF_VALUE) *dn_sk, *attr_sk = NULL;
+    STACK_OF(CONF_VALUE) *dn_sk = NULL, *attr_sk = NULL;
     char *tmp, *dn_sect, *attr_sect;
 
     tmp = NCONF_get_string(req_conf, section, PROMPT);
@@ -1019,20 +1008,18 @@ static int make_REQ(X509_REQ *req, EVP_PKEY *pkey, char *subj, int multirdn,
 
     dn_sect = NCONF_get_string(req_conf, section, DISTINGUISHED_NAME);
     if (dn_sect == NULL) {
-        BIO_printf(bio_err, "unable to find '%s' in config\n",
-                   DISTINGUISHED_NAME);
-        goto err;
-    }
-    dn_sk = NCONF_get_section(req_conf, dn_sect);
-    if (dn_sk == NULL) {
-        BIO_printf(bio_err, "unable to get '%s' section\n", dn_sect);
-        goto err;
+        ERR_clear_error();
+    } else {
+        dn_sk = NCONF_get_section(req_conf, dn_sect);
+        if (dn_sk == NULL) {
+            BIO_printf(bio_err, "unable to get '%s' section\n", dn_sect);
+            goto err;
+        }
     }
 
     attr_sect = NCONF_get_string(req_conf, section, ATTRIBUTES);
     if (attr_sect == NULL) {
         ERR_clear_error();
-        attr_sk = NULL;
     } else {
         attr_sk = NCONF_get_section(req_conf, attr_sect);
         if (attr_sk == NULL) {
@@ -1583,20 +1570,17 @@ static EVP_PKEY_CTX *set_keygen_ctx(const char *gstr,
 
     if (gctx == NULL) {
         BIO_puts(bio_err, "Error allocating keygen context\n");
-        ERR_print_errors(bio_err);
         return NULL;
     }
 
     if (EVP_PKEY_keygen_init(gctx) <= 0) {
         BIO_puts(bio_err, "Error initializing keygen context\n");
-        ERR_print_errors(bio_err);
         EVP_PKEY_CTX_free(gctx);
         return NULL;
     }
     if ((*pkey_type == EVP_PKEY_RSA) && (keylen != -1)) {
         if (EVP_PKEY_CTX_set_rsa_keygen_bits(gctx, keylen) <= 0) {
             BIO_puts(bio_err, "Error setting RSA keysize\n");
-            ERR_print_errors(bio_err);
             EVP_PKEY_CTX_free(gctx);
             return NULL;
         }
diff --git a/apps/srp.c b/apps/srp.c
index 3d8ce3e7c6..f7edfa9930 100644
--- a/apps/srp.c
+++ b/apps/srp.c
@@ -338,10 +338,7 @@ int srp_main(int argc, char **argv)
         if (configfile == NULL)
             configfile = default_config_file;
 
-        if (verbose)
-            BIO_printf(bio_err, "Using configuration from %s\n",
-                       configfile);
-        conf = app_load_config(configfile);
+        conf = app_load_config_verbose(configfile, verbose);
         if (conf == NULL)
             goto end;
         if (configfile != default_config_file && !app_load_modules(conf))
diff --git a/crypto/conf/conf_api.c b/crypto/conf/conf_api.c
index d64cc5031a..5133114fc8 100644
--- a/crypto/conf/conf_api.c
+++ b/crypto/conf/conf_api.c
@@ -27,7 +27,7 @@ CONF_VALUE *_CONF_get_section(const CONF *conf, const char *section)
         return NULL;
     vv.name = NULL;
     vv.section = (char *)section;
-    return lh_CONF_VALUE_retrieve(conf->data, &vv);
+    return conf->data != NULL ? lh_CONF_VALUE_retrieve(conf->data, &vv) : NULL;
 }
 
 STACK_OF(CONF_VALUE) *_CONF_get_section_values(const CONF *conf,
@@ -72,6 +72,8 @@ char *_CONF_get_string(const CONF *conf, const char *section,
         return NULL;
     if (conf == NULL)
         return ossl_safe_getenv(name);
+    if (conf->data == NULL)
+        return NULL;
     if (section != NULL) {
         vv.name = (char *)name;
         vv.section = (char *)section;
diff --git a/crypto/conf/conf_def.c b/crypto/conf/conf_def.c
index 3f63a5f88d..a7f5677a26 100644
--- a/crypto/conf/conf_def.c
+++ b/crypto/conf/conf_def.c
@@ -239,11 +239,12 @@ static int def_load_bio(CONF *conf, BIO *in, long *line)
         p = &(buff->data[bufnum]);
         *p = '\0';
  read_retry:
-        BIO_gets(in, p, CONFBUFSIZE - 1);
+        if (in != NULL && BIO_gets(in, p, CONFBUFSIZE - 1) < 0)
+            goto err;
         p[CONFBUFSIZE - 1] = '\0';
         ii = i = strlen(p);
         if (i == 0 && !again) {
-            /* the currently processed BIO is at EOF */
+            /* the currently processed BIO is NULL or at EOF */
             BIO *parent;
 
 #ifndef OPENSSL_NO_POSIX_IO
diff --git a/crypto/conf/conf_mod.c b/crypto/conf/conf_mod.c
index cb1bf7cd3c..8de3222c34 100644
--- a/crypto/conf/conf_mod.c
+++ b/crypto/conf/conf_mod.c
@@ -156,11 +156,6 @@ int CONF_modules_load_file_ex(OSSL_LIB_CTX *libctx, const char *filename,
     CONF *conf = NULL;
     int ret = 0, diagnostics = 0;
 
-    ERR_set_mark();
-    conf = NCONF_new_ex(libctx, NULL);
-    if (conf == NULL)
-        goto err;
-
     if (filename == NULL) {
         file = CONF_get1_default_config_file();
         if (file == NULL)
@@ -169,6 +164,11 @@ int CONF_modules_load_file_ex(OSSL_LIB_CTX *libctx, const char *filename,
         file = (char *)filename;
     }
 
+    ERR_set_mark();
+    conf = NCONF_new_ex(libctx, NULL);
+    if (conf == NULL)
+        goto err;
+
     if (NCONF_load(conf, file, NULL) <= 0) {
         if ((flags & CONF_MFLAGS_IGNORE_MISSING_FILE) &&
             (ERR_GET_REASON(ERR_peek_last_error()) == CONF_R_NO_SUCH_FILE)) {
@@ -539,7 +539,6 @@ void CONF_module_set_usr_data(CONF_MODULE *pmod, void *usr_data)
 }
 
 /* Return default config file name */
-
 char *CONF_get1_default_config_file(void)
 {
     const char *t;
diff --git a/doc/man1/openssl.pod b/doc/man1/openssl.pod
index abb5d5e3e4..3396f684f9 100644
--- a/doc/man1/openssl.pod
+++ b/doc/man1/openssl.pod
@@ -83,10 +83,13 @@ Many commands use an external configuration file for some or all of their
 arguments and have a B<-config> option to specify that file.
 The default name of the file is F<openssl.cnf> in the default certificate
 storage area, which can be determined from the L<openssl-version(1)>
-command. This can be used to load modules.
-The environment variable B<OPENSSL_CONF> can be used to specify
-a different location of the file.
-See L<openssl-env(7)>.
+command using the B<-d> or B<-a> option.
+The environment variable B<OPENSSL_CONF> can be used to specify a different
+file location or to disable loading a configuration (using the empty string).
+
+Among others, the configuration file can be used to load modules
+and to specify parameters for generating certificates and random numbers.
+See L<config(5)> for details.
 
 =head2 Standard Commands
 
diff --git a/doc/man3/CONF_modules_load_file.pod b/doc/man3/CONF_modules_load_file.pod
index fff60c192e..59e8f6f34c 100644
--- a/doc/man3/CONF_modules_load_file.pod
+++ b/doc/man3/CONF_modules_load_file.pod
@@ -2,6 +2,7 @@
 
 =head1 NAME
 
+CONF_get1_default_config_file,
 CONF_modules_load_file_ex, CONF_modules_load_file, CONF_modules_load
 - OpenSSL configuration functions
 
@@ -9,6 +10,7 @@ CONF_modules_load_file_ex, CONF_modules_load_file, CONF_modules_load
 
  #include <openssl/conf.h>
 
+ char *CONF_get1_default_config_file(void);
  int CONF_modules_load_file_ex(OSSL_LIB_CTX *libctx, const char *filename,
                                const char *appname, unsigned long flags);
  int CONF_modules_load_file(const char *filename, const char *appname,
@@ -18,9 +20,17 @@ CONF_modules_load_file_ex, CONF_modules_load_file, CONF_modules_load
 
 =head1 DESCRIPTION
 
+The function CONF_get1_default_config_file() determines the default
+configuration file pathname as follows.
+If the B<OPENSSL_CONF> environment variable is set its value is returned.
+Else the function returns the path obtained using
+L<X509_get_default_cert_area(3)> with the filename C<"openssl.cnf"> appended.
+The caller is responsible for freeing any string returned.
+
 The function CONF_modules_load_file_ex() configures OpenSSL using
 library context B<libctx> file B<filename> and application name B<appname>.
-If B<filename> is NULL the standard OpenSSL configuration file is used.
+If B<filename> is NULL the standard OpenSSL configuration file is used
+as determined by calling CONF_get1_default_config_file().
 If B<appname> is NULL the standard OpenSSL application name B<openssl_conf> is
 used.
 The behaviour can be customized using B<flags>. Note that, the error suppressing
diff --git a/doc/man5/config.pod b/doc/man5/config.pod
index 45165f20ec..de4b5aec59 100644
--- a/doc/man5/config.pod
+++ b/doc/man5/config.pod
@@ -502,7 +502,7 @@ F<sample>.
 
 =item B<OPENSSL_CONF>
 
-The path to the config file.
+The path to the config file, or the empty string for none.
 Ignored in set-user-ID and set-group-ID programs.
 
 =item B<OPENSSL_ENGINES>
diff --git a/doc/man7/openssl-env.pod b/doc/man7/openssl-env.pod
index 8e131affb7..4702615e8a 100644
--- a/doc/man7/openssl-env.pod
+++ b/doc/man7/openssl-env.pod
@@ -28,7 +28,7 @@ and by the B<CA.pl> script (see L<CA.pl(1)/NOTES>
 
 Specifies the path to a configuration file and the directory for
 included files.
-See L<openssl(1)> and L<config(5)>.
+See L<config(5)>.
 
 =item B<OPENSSL_CONFIG>
 
diff --git a/util/missingcrypto.txt b/util/missingcrypto.txt
index b547e52858..a4da3bc3fb 100644
--- a/util/missingcrypto.txt
+++ b/util/missingcrypto.txt
@@ -379,7 +379,6 @@ COMP_zlib(3)
 CONF_dump_bio(3)
 CONF_dump_fp(3)
 CONF_free(3)
-CONF_get1_default_config_file(3)
 CONF_get_number(3)
 CONF_get_section(3)
 CONF_get_string(3)
diff --git a/util/missingcrypto111.txt b/util/missingcrypto111.txt
index 9e945703dc..4be52cf25c 100644
--- a/util/missingcrypto111.txt
+++ b/util/missingcrypto111.txt
@@ -403,7 +403,6 @@ COMP_zlib(3)
 CONF_dump_bio(3)
 CONF_dump_fp(3)
 CONF_free(3)
-CONF_get1_default_config_file(3)
 CONF_get_number(3)
 CONF_get_section(3)
 CONF_get_string(3)