[Openvpn-devel,v2,12/20,OSSL,3.0] Allow loading of non default providers

Message ID 20211019182332.613155-15-arne@rfc2549.org
State Superseded
Headers show
Series
  • Untitled series #1307
Related show

Commit Message

Arne Schwabe Oct. 19, 2021, 6:23 p.m.
This allows OpenVPN to load non-default providers. This is mainly
useful for loading the legacy provider with --provider legacy:default

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
---
 doc/man-sections/generic-options.rst | 10 ++++++++++
 src/openvpn/crypto_backend.h         |  7 +++++++
 src/openvpn/crypto_mbedtls.c         |  8 ++++++++
 src/openvpn/crypto_openssl.c         | 29 ++++++++++++++++++++++++++++
 src/openvpn/openvpn.c                |  4 ++++
 src/openvpn/options.c                |  4 ++++
 src/openvpn/options.h                |  1 +
 7 files changed, 63 insertions(+)

Patch

diff --git a/doc/man-sections/generic-options.rst b/doc/man-sections/generic-options.rst
index e6c1fe455..f5b8a9135 100644
--- a/doc/man-sections/generic-options.rst
+++ b/doc/man-sections/generic-options.rst
@@ -280,6 +280,16 @@  which mode OpenVPN is configured as.
   This option solves the problem by persisting keys across :code:`SIGUSR1`
   resets, so they don't need to be re-read.
 
+--provider providers
+  Load the : separated list of (OpenSSL) providers. This is mainly useful for
+  using an external provider for key management like tpm2-openssl or to load
+  the legacy provider with
+
+  ::
+
+      --provider "legacy:default"
+
+
 --remap-usr1 signal
   Control whether internally or externally generated :code:`SIGUSR1` signals
   are remapped to :code:`SIGHUP` (restart without persisting state) or
diff --git a/src/openvpn/crypto_backend.h b/src/openvpn/crypto_backend.h
index cc897acf4..fa265e6c2 100644
--- a/src/openvpn/crypto_backend.h
+++ b/src/openvpn/crypto_backend.h
@@ -78,6 +78,13 @@  void crypto_clear_error(void);
  */
 void crypto_init_lib_engine(const char *engine_name);
 
+
+/**
+ * Load the given (OpenSSL) providers
+ * @param providers list of providers to load, seperated by :
+ */
+void crypto_init_lib_provider(const char *providers);
+
 #ifdef DMALLOC
 /*
  * OpenSSL memory debugging.  If dmalloc debugging is enabled, tell
diff --git a/src/openvpn/crypto_mbedtls.c b/src/openvpn/crypto_mbedtls.c
index 2f7f00d19..e6ed1ae99 100644
--- a/src/openvpn/crypto_mbedtls.c
+++ b/src/openvpn/crypto_mbedtls.c
@@ -70,6 +70,14 @@  crypto_init_lib_engine(const char *engine_name)
         "available");
 }
 
+void crypto_init_lib_provider(const char *providers)
+{
+    if (providers)
+    {
+        msg(M_WARN, "Note: mbed TLS provider functionality is not available");
+    }
+}
+
 /*
  *
  * Functions related to the core crypto library
diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c
index 407ea4a7c..1900ccc1b 100644
--- a/src/openvpn/crypto_openssl.c
+++ b/src/openvpn/crypto_openssl.c
@@ -54,6 +54,9 @@ 
 #if (OPENSSL_VERSION_NUMBER >= 0x10100000L) && !defined(LIBRESSL_VERSION_NUMBER)
 #include <openssl/kdf.h>
 #endif
+#if OPENSSL_VERSION_NUMBER >= 0x30000000L
+#include <openssl/provider.h>
+#endif
 
 /*
  * Check for key size creepage.
@@ -145,6 +148,32 @@  crypto_init_lib_engine(const char *engine_name)
 #endif
 }
 
+void
+crypto_init_lib_provider(const char *providers)
+{
+    if (!providers)
+    {
+        return;
+    }
+#if OPENSSL_VERSION_NUMBER >= 0x30000000L
+    struct gc_arena gc = gc_new();
+    char *tmp_providers = string_alloc(providers, &gc);
+
+    const char *provname;
+    while ((provname = strsep(&tmp_providers, ":")))
+    {
+        /* Load providers into the default (NULL) library context */
+        OSSL_PROVIDER* provider = OSSL_PROVIDER_load(NULL, provname);
+        if (!provider)
+        {
+            crypto_msg(M_FATAL, "failed to load provider '%s'", provname);
+        }
+    }
+#else  /* OPENSSL_VERSION_NUMBER >= 0x30000000L */
+    msg(M_WARN, "Note: OpenSSL hardware crypto engine functionality is not available");
+#endif
+}
+
 /*
  *
  * Functions related to the core crypto library
diff --git a/src/openvpn/openvpn.c b/src/openvpn/openvpn.c
index f8e94509f..3c9bcf885 100644
--- a/src/openvpn/openvpn.c
+++ b/src/openvpn/openvpn.c
@@ -112,6 +112,10 @@  void init_early(struct context *c)
     /* init verbosity and mute levels */
     init_verb_mute(c, IVM_LEVEL_1);
 
+    /* Initialise OpenVPN provider, this needs to be intialised this
+    * early since option post processing and also openssl info
+    * printing depends on it */
+    crypto_init_lib_provider((*c).options.providers);
 }
 
 static void uninit_early(struct context *c)
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index ed2dcd53d..ab7b00783 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -8178,6 +8178,10 @@  add_option(struct options *options,
             options->engine = "auto";
         }
     }
+    else if (streq(p[0], "provider") && p[1] && !p[2])
+    {
+        options->providers = p[1];
+    }
 #endif /* ENABLE_CRYPTO_MBEDTLS */
 #ifdef ENABLE_PREDICTION_RESISTANCE
     else if (streq(p[0], "use-prediction-resistance") && !p[1])
diff --git a/src/openvpn/options.h b/src/openvpn/options.h
index 98c21a2a8..6759f1950 100644
--- a/src/openvpn/options.h
+++ b/src/openvpn/options.h
@@ -521,6 +521,7 @@  struct options
     const char *prng_hash;
     int prng_nonce_secret_len;
     const char *engine;
+    const char *providers;
     bool replay;
     bool mute_replay_warnings;
     int replay_window;