gnu: curl: Make libcurl respect SSL_CERT_DIR and SSL_CERT_FILE.

* gnu/packages/patches/curl-use-ssl-cert-env.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/curl.scm (curl)[source]: Use the patch.
[native-search-paths]: Add the new variables.

Signed-off-by: Marius Bakke <mbakke@fastmail.com>

gnu/local.mk

@@ -789,6 +789,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/csvkit-fix-tests.patch			\
   %D%/packages/patches/clucene-contribs-lib.patch               \
   %D%/packages/patches/cube-nocheck.patch			\
+  %D%/packages/patches/curl-use-ssl-cert-env.patch		\
   %D%/packages/patches/cursynth-wave-rand.patch			\
   %D%/packages/patches/cvs-CVE-2017-12836.patch		\
   %D%/packages/patches/cyrus-sasl-ac-try-run-fix.patch		\

gnu/packages/curl.scm

@@ -9,6 +9,7 @@
 ;;; Copyright © 2017, 2018 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2018 Roel Janssen <roel@gnu.org>
 ;;; Copyright © 2019 Ricardo Wurmus <rekado@elephly.net>
+;;; Copyright © 2020 Jakub Kądziołka <kuba@kadziolka.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -57,7 +58,8 @@
                                 version ".tar.xz"))
             (sha256
              (base32
-              "0nh3j90w6b97wqcgxjfq55qhkz9s38955fbhwzv2fsi7483j895p"))))
+              "0nh3j90w6b97wqcgxjfq55qhkz9s38955fbhwzv2fsi7483j895p"))
+            (patches (search-patches "curl-use-ssl-cert-env.patch"))))
    (build-system gnu-build-system)
    (outputs '("out"
               "doc"))                             ;1.2 MiB of man3 pages
@@ -74,10 +76,20 @@
        ("pkg-config" ,pkg-config)
        ("python" ,python-wrapper)))
    (native-search-paths
-    ;; Note: This search path is respected by the `curl` command-line tool only.
+    ;; These variables are introduced by libcurl-use-ssl-cert-env.patch.
-    ;; Ideally we would bake this into libcurl itself so other users can benefit,
-    ;; but it's not supported upstream due to thread safety concerns.
     (list (search-path-specification
+           (variable "SSL_CERT_DIR")
+           (separator #f)                        ;single entry
+           (files '("etc/ssl/certs")))
+          (search-path-specification
+           (variable "SSL_CERT_FILE")
+           (file-type 'regular)
+           (separator #f)                        ;single entry
+           (files '("etc/ssl/certs/ca-certificates.crt")))
+          ;; Note: This search path is respected by the `curl` command-line
+          ;; tool only.  Patching libcurl to read it too would bring no
+          ;; advantages and require maintaining a more complex patch.
+          (search-path-specification
            (variable "CURL_CA_BUNDLE")
            (file-type 'regular)
            (separator #f)                         ;single entry

gnu/packages/patches/curl-use-ssl-cert-env.patch

@@ -0,0 +1,64 @@
+Make libcurl respect the SSL_CERT_{DIR,FILE} variables by default. The variables
+are fetched during initialization to preserve thread-safety (curl_global_init(3)
+must be called when no other threads exist).
+
+This fixes network functionality in rust:cargo, and probably removes the need
+for other future workarounds.
+===================================================================
+--- curl-7.66.0.orig/lib/easy.c	2020-01-02 15:43:11.883921171 +0100
++++ curl-7.66.0/lib/easy.c	2020-01-02 16:18:54.691882797 +0100
+@@ -134,6 +134,9 @@
+ #  pragma warning(default:4232) /* MSVC extension, dllimport identity */
+ #endif
+ 
++char * Curl_ssl_cert_dir = NULL;
++char * Curl_ssl_cert_file = NULL;
++
+ /**
+  * curl_global_init() globally initializes curl given a bitwise set of the
+  * different features of what to initialize.
+@@ -155,6 +158,9 @@
+ #endif
+   }
+ 
++  Curl_ssl_cert_dir = curl_getenv("SSL_CERT_DIR");
++  Curl_ssl_cert_file = curl_getenv("SSL_CERT_FILE");
++
+   if(!Curl_ssl_init()) {
+     DEBUGF(fprintf(stderr, "Error: Curl_ssl_init failed\n"));
+     return CURLE_FAILED_INIT;
+@@ -260,6 +266,9 @@
+   Curl_ssl_cleanup();
+   Curl_resolver_global_cleanup();
+ 
++  free(Curl_ssl_cert_dir);
++  free(Curl_ssl_cert_file);
++
+ #ifdef WIN32
+   Curl_win32_cleanup(init_flags);
+ #endif
+diff -ur curl-7.66.0.orig/lib/url.c curl-7.66.0/lib/url.c
+--- curl-7.66.0.orig/lib/url.c	2020-01-02 15:43:11.883921171 +0100
++++ curl-7.66.0/lib/url.c	2020-01-02 16:21:11.563880346 +0100
+@@ -524,6 +524,21 @@
+     if(result)
+       return result;
+ #endif
++    extern char * Curl_ssl_cert_dir;
++    extern char * Curl_ssl_cert_file;
++    if(Curl_ssl_cert_dir) {
++        if(result = Curl_setstropt(&set->str[STRING_SSL_CAPATH_ORIG], Curl_ssl_cert_dir))
++            return result;
++        if(result = Curl_setstropt(&set->str[STRING_SSL_CAPATH_PROXY], Curl_ssl_cert_dir))
++            return result;
++    }
++
++    if(Curl_ssl_cert_file) {
++        if(result = Curl_setstropt(&set->str[STRING_SSL_CAFILE_ORIG], Curl_ssl_cert_file))
++            return result;
++        if(result = Curl_setstropt(&set->str[STRING_SSL_CAFILE_PROXY], Curl_ssl_cert_file))
++            return result;
++    }
+   }
+ 
+   set->wildcard_enabled = FALSE;