Network: only enable it if PROJ_NETWORK=ON or proj_context_set_enable_network(ctx, true)

5 files changed, 108 insertions, 7 deletions

diff --git a/scripts/reference_exported_symbols.txt b/scripts/reference_exported_symbols.txt
index 6e4e5302..9d7d400a 100644
--- a/scripts/reference_exported_symbols.txt
+++ b/scripts/reference_exported_symbols.txt
@@ -794,6 +794,7 @@ proj_context_get_use_proj4_init_rules
 proj_context_guess_wkt_dialect
 proj_context_set_autoclose_database
 proj_context_set_database_path
+proj_context_set_enable_network
 proj_context_set_file_finder
 proj_context_set_network_callbacks
 proj_context_set(PJconsts*, projCtx_t*)
diff --git a/src/filemanager.cpp b/src/filemanager.cpp
index ea0a63ea..cd738d5e 100644
--- a/src/filemanager.cpp
+++ b/src/filemanager.cpp
@@ -63,9 +63,9 @@ class MyMutex {
 
 //! @cond Doxygen_Suppress
 
-NS_PROJ_START
+using namespace NS_PROJ::internal;
 
-using namespace internal;
+NS_PROJ_START
 
 // ---------------------------------------------------------------------------
 
@@ -488,6 +488,14 @@ std::unique_ptr<File> FileManager::open(PJ_CONTEXT *ctx, const char *filename) {
     }
 #endif
     if (starts_with(filename, "http://") || starts_with(filename, "https://")) {
+        if (!pj_context_is_network_enabled(ctx)) {
+            pj_log(
+                ctx, PJ_LOG_ERROR,
+                "Attempt at accessing remote resource not authorized. Either "
+                "set PROJ_NETWORK=ON or "
+                "proj_context_set_enable_network(ctx, TRUE)");
+            return nullptr;
+        }
         return NetworkFile::open(ctx, filename);
     }
     return FileStdio::open(ctx, filename);
@@ -756,3 +764,49 @@ int proj_context_set_network_callbacks(
     ctx->networking.user_data = user_data;
     return true;
 }
+
+// ---------------------------------------------------------------------------
+
+/** Enable or disable network access.
+*
+* @param ctx PROJ context, or NULL
+* @param enable TRUE if network access is allowed.
+* @return TRUE if network access is possible. That is either libcurl is
+*         available, or an alternate interface has been set.
+*/
+int proj_context_set_enable_network(PJ_CONTEXT *ctx, int enable) {
+    if (ctx == nullptr) {
+        ctx = pj_get_default_ctx();
+    }
+    ctx->networking.enabled_env_variable_checked = true;
+    ctx->networking.enabled = enable != FALSE;
+#ifdef CURL_ENABLED
+    return ctx->networking.enabled;
+#else
+    return ctx->networking.enabled &&
+           ctx->networking.open != NS_PROJ::no_op_network_open;
+#endif
+}
+
+// ---------------------------------------------------------------------------
+
+//! @cond Doxygen_Suppress
+
+bool pj_context_is_network_enabled(PJ_CONTEXT *ctx) {
+    if (ctx == nullptr) {
+        ctx = pj_get_default_ctx();
+    }
+    if (ctx->networking.enabled_env_variable_checked) {
+        return ctx->networking.enabled;
+    }
+    const char *enabled = getenv("PROJ_NETWORK");
+    if (enabled && enabled[0] != '\0') {
+        ctx->networking.enabled = ci_equal(enabled, "ON") ||
+                                  ci_equal(enabled, "YES") ||
+                                  ci_equal(enabled, "TRUE");
+    }
+    ctx->networking.enabled_env_variable_checked = true;
+    return ctx->networking.enabled;
+}
+
+//! @endcond
diff --git a/src/proj.h b/src/proj.h
index 95bbacd1..4f7878a4 100644
--- a/src/proj.h
+++ b/src/proj.h
@@ -421,6 +421,9 @@ int PROJ_DLL proj_context_set_network_callbacks(
     proj_network_get_last_error_type get_last_error_cbk,
     void* user_data);
 
+int PROJ_DLL proj_context_set_enable_network(PJ_CONTEXT* ctx,
+                                             int enabled);
+
 /*! @cond Doxygen_Suppress */
 
 /* Manage the transformation definition object PJ */
diff --git a/src/proj_internal.h b/src/proj_internal.h
index 0c148d02..d54d8fb9 100644
--- a/src/proj_internal.h
+++ b/src/proj_internal.h
@@ -668,6 +668,8 @@ struct projCppContext;
 
 struct projNetworkCallbacksAndData
 {
+    bool enabled = false;
+    bool enabled_env_variable_checked = false; // whereas we have checked PROJ_NETWORK env variable
     proj_network_open_cbk_type open = nullptr;
     proj_network_close_cbk_type close = nullptr;
     proj_network_get_header_value_cbk_type get_header_value = nullptr;
@@ -824,6 +826,8 @@ PJ *pj_create_argv_internal (PJ_CONTEXT *ctx, int argc, char **argv);
 
 void pj_pipeline_assign_context_to_steps( PJ* P, PJ_CONTEXT* ctx );
 
+bool pj_context_is_network_enabled(PJ_CONTEXT* ctx);
+
 /* classic public API */
 #include "proj_api.h"
 
diff --git a/test/unit/test_network.cpp b/test/unit/test_network.cpp
index 5940814b..ba592da4 100644
--- a/test/unit/test_network.cpp
+++ b/test/unit/test_network.cpp
@@ -30,6 +30,7 @@
 
 #include <memory>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "proj_internal.h"
 #include <proj.h>
@@ -77,18 +78,54 @@ TEST(networking, initial_check) {
 
 // ---------------------------------------------------------------------------
 
+static void silent_logger(void *, int, const char *) {}
+
+// ---------------------------------------------------------------------------
+
 TEST(networking, basic) {
-    auto P = proj_create(
-        PJ_DEFAULT_CTX,
+    const char *pipeline =
         "+proj=pipeline "
         "+step +proj=unitconvert +xy_in=deg +xy_out=rad "
         "+step +proj=hgridshift +grids=https://cdn.proj.org/ntf_r93.tif "
-        "+step +proj=unitconvert +xy_in=rad +xy_out=deg ");
+        "+step +proj=unitconvert +xy_in=rad +xy_out=deg";
+
+    // network access disabled by default
+    auto ctx = proj_context_create();
+    proj_log_func(ctx, nullptr, silent_logger);
+    auto P = proj_create(ctx, pipeline);
+    ASSERT_EQ(P, nullptr);
+    proj_context_destroy(ctx);
+
+#ifdef CURL_ENABLED
+    // enable through env variable
+    ctx = proj_context_create();
+    putenv(const_cast<char *>("PROJ_NETWORK=ON"));
+    P = proj_create(ctx, pipeline);
+    if (networkAccessOK) {
+        ASSERT_NE(P, nullptr);
+    }
+    proj_destroy(P);
+    proj_context_destroy(ctx);
+    putenv(const_cast<char *>("PROJ_NETWORK="));
+#endif
+
+    // still disabled
+    ctx = proj_context_create();
+    proj_log_func(ctx, nullptr, silent_logger);
+    P = proj_create(ctx, pipeline);
+    ASSERT_EQ(P, nullptr);
+    proj_context_destroy(ctx);
+
+    // enable through API
+    ctx = proj_context_create();
+    proj_context_set_enable_network(ctx, true);
+    P = proj_create(ctx, pipeline);
 #ifdef CURL_ENABLED
     if (networkAccessOK) {
         ASSERT_NE(P, nullptr);
     } else {
         ASSERT_EQ(P, nullptr);
+        proj_context_destroy(ctx);
         return;
     }
     double lon = 2;
@@ -102,16 +139,16 @@ TEST(networking, basic) {
 #else
     ASSERT_EQ(P, nullptr);
 #endif
+    proj_context_destroy(ctx);
 }
 
 // ---------------------------------------------------------------------------
 
 #ifdef CURL_ENABLED
 
-static void silent_logger(void *, int, const char *) {}
-
 TEST(networking, curl_invalid_resource) {
     auto ctx = proj_context_create();
+    proj_context_set_enable_network(ctx, true);
     proj_log_func(ctx, nullptr, silent_logger);
     auto P = proj_create(
         ctx, "+proj=hgridshift +grids=https://i_do_not.exist/my.tif");
@@ -364,6 +401,7 @@ static const char *get_last_error_cbk(PJ_CONTEXT * /*ctx*/,
 
 TEST(networking, custom) {
     auto ctx = proj_context_create();
+    proj_context_set_enable_network(ctx, true);
     ExchangeWithCallback exchange;
     ASSERT_TRUE(proj_context_set_network_callbacks(
         ctx, open_cbk, close_cbk, get_header_value_cbk, read_range_cbk,
@@ -499,6 +537,7 @@ TEST(networking, custom) {
 
 TEST(networking, getfilesize) {
     auto ctx = proj_context_create();
+    proj_context_set_enable_network(ctx, true);
     ExchangeWithCallback exchange;
     ASSERT_TRUE(proj_context_set_network_callbacks(
         ctx, open_cbk, close_cbk, get_header_value_cbk, read_range_cbk,