Merge pull request #4319 from Ma27/store-v6-addr

libstore/openStore: fix stores with IPv6 addresses

src/libstore/store-api.cc

@@ -10,6 +10,8 @@
 #include "archive.hh"
 #include "callback.hh"
 
+#include <regex>
+
 namespace nix {
 
 
@@ -1091,6 +1093,34 @@ std::shared_ptr<Store> openFromNonUri(const std::string & uri, const Store::Para
     }
 }
 
+// The `parseURL` function supports both IPv6 URIs as defined in
+// RFC2732, but also pure addresses. The latter one is needed here to
+// connect to a remote store via SSH (it's possible to do e.g. `ssh root@::1`).
+//
+// This function now ensures that a usable connection string is available:
+// * If the store to be opened is not an SSH store, nothing will be done.
+// * If the URL looks like `root@[::1]` (which is allowed by the URL parser and probably
+//   needed to pass further flags), it
+//   will be transformed into `root@::1` for SSH (same for `[::1]` -> `::1`).
+// * If the URL looks like `root@::1` it will be left as-is.
+// * In any other case, the string will be left as-is.
+static std::string extractConnStr(const std::string &proto, const std::string &connStr)
+{
+    if (proto.rfind("ssh") != std::string::npos) {
+        std::smatch result;
+        std::regex v6AddrRegex("^((.*)@)?\\[(.*)\\]$");
+
+        if (std::regex_match(connStr, result, v6AddrRegex)) {
+            if (result[1].matched) {
+                return result.str(1) + result.str(3);
+            }
+            return result.str(3);
+        }
+    }
+
+    return connStr;
+}
+
 ref<Store> openStore(const std::string & uri_,
     const Store::Params & extraParams)
 {
@@ -1099,7 +1129,10 @@ ref<Store> openStore(const std::string & uri_,
         auto parsedUri = parseURL(uri_);
         params.insert(parsedUri.query.begin(), parsedUri.query.end());
 
-        auto baseURI = parsedUri.authority.value_or("") + parsedUri.path;
+        auto baseURI = extractConnStr(
+            parsedUri.scheme,
+            parsedUri.authority.value_or("") + parsedUri.path
+        );
 
         for (auto implem : *Implementations::registered) {
             if (implem.uriSchemes.count(parsedUri.scheme)) {

src/libutil/url-parts.hh

@@ -8,7 +8,8 @@ namespace nix {
 // URI stuff.
 const static std::string pctEncoded = "(?:%[0-9a-fA-F][0-9a-fA-F])";
 const static std::string schemeRegex = "(?:[a-z][a-z0-9+.-]*)";
-const static std::string ipv6AddressRegex = "(?:\\[[0-9a-fA-F:]+\\])";
+const static std::string ipv6AddressSegmentRegex = "[0-9a-fA-F:]+";
+const static std::string ipv6AddressRegex = "(?:\\[" + ipv6AddressSegmentRegex + "\\]|" + ipv6AddressSegmentRegex + ")";
 const static std::string unreservedRegex = "(?:[a-zA-Z0-9-._~])";
 const static std::string subdelimsRegex = "(?:[!$&'\"()*+,;=])";
 const static std::string hostnameRegex = "(?:(?:" + unreservedRegex + "|" + pctEncoded + "|" + subdelimsRegex + ")*)";