Correctly decode multi-share SLIP-39 URs.

* Fixed bug where multi-share URs like SLIP-39 were not decoded correctly due to support for multi-part URs being added. Seedtool now supports *either* decoding a multi-part UR or a multi-share UR where the shares are encoded as URs, but not both simultaneously.
* Added example to MANUAL of decoding URs containing SLIP-39 shares.

Author: wolfmcnally

.vscode/launch.json

@@ -7,7 +7,7 @@
             "type": "lldb",
             "request": "launch",
             "program": "${workspaceFolder}/src/seedtool",
-            "args": [ "--in", "ur" ],
+            "args": [ ],
             "cwd": "${workspaceFolder}/src",
             "preLaunchTask": "Build"
         }

MANUAL.md

@@ -1,6 +1,6 @@
 # 🌱 Seedtool
 
-**Version 0.7.0**<br/>**August 12, 2020**
+**Version 0.7.1**<br/>**August 21, 2020**
 
 *Copyright © 2020 by Blockchain Commons, LLC*<br/>*Licensed under the "BSD-2-Clause Plus Patent License"*
 
@@ -933,8 +933,27 @@ ur:crypto-slip39/18-9/ltbgascfadrkcyrkfmesjlhdeyihiajlkoihjpiojkjyhsieinkpjniojo
 9d347f841a4e2ce6bc886e1aee74d824
 ```
 
+The example above uses a multi-part UR to encode all the shares of a SLIP-39 seed. Each of the parts of a multi-part UR are *not* equivalent to a share of a multi-share recovery tool like SLIP-39. Seedtool can also decode a SLIP-39 seed from one or more single-part URs that each represent one share of a SLIP-39.
+
+```
+#
+# Recover a SLIP-39 seed using 2 of 3 shares. Each UR is one share.
+#
+
+$ seedtool --in ur
+ur:crypto-slip39/oyadlymwihkojliniaihishsiahsieihjniniaishsiahsieihjniniaiehsiainieiohsjtksinihjykkihiojpinjzjzieiyhsktjtiohskpiajyinjljtiokoihjpieiniajyiyjyihjnjojzihieisjlkpjpiojzinidjphsjpkkihiokpihjkjyiejohsjohsiyjpiskkjyisjnihjkhskoihjpiejlkoihjtihjphsjkjokkisihksiaishsjtioihiyjyjphsiajejkbnvsckem
+ur:crypto-slip39/oyadlymwihkojliniaihishsiahsieihjniniaishsiahsieihjniniaiyhsioihjtiakkiyhsiyjphsinieiyiahsjtkkjljtisjkkkjnjohsjyiskkiyiajpihieinjyiojpihkoihjtkpihihiejpjlkoihiohsiekohsjtiaihiojzhsktjkkpinjyihiahsjpiojlisidinjpjyisiehskkieieihjtkkiyjphsiainjkjnihhsjohsjpjyiyjkhsiyhsjpiniojyjphsiyiyiniaiyihjphsjkihjptytpolwy
+^D
+e3b0c44298fc1c149afbf4c8996fb924
+```
+
 ## Version History
 
+### 0.7.1, 8/21/2020
+
+* Fixed bug where multi-share URs like SLIP-39 were not decoded correctly due to support for multi-part URs being added. Seedtool now supports *either* decoding a multi-part UR or a multi-share UR where the shares are encoded as URs, but not both simultaneously.
+* Added example to MANUAL of decoding URs containing SLIP-39 shares.
+
 ### 0.7.0, 8/12/2020
 
 * Now using bc-ur for UR encoding/decoding. Support multi-part fountain encoding/decoding.

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for bc-seedtool-cli 0.7.0.
+# Generated by GNU Autoconf 2.69 for bc-seedtool-cli 0.7.1.
 #
 #
 # Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
@@ -577,8 +577,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='bc-seedtool-cli'
 PACKAGE_TARNAME='bc-seedtool-cli'
-PACKAGE_VERSION='0.7.0'
-PACKAGE_STRING='bc-seedtool-cli 0.7.0'
+PACKAGE_VERSION='0.7.1'
+PACKAGE_STRING='bc-seedtool-cli 0.7.1'
 PACKAGE_BUGREPORT=''
 PACKAGE_URL=''
 
@@ -1232,7 +1232,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures bc-seedtool-cli 0.7.0 to adapt to many kinds of systems.
+\`configure' configures bc-seedtool-cli 0.7.1 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1293,7 +1293,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of bc-seedtool-cli 0.7.0:";;
+     short | recursive ) echo "Configuration of bc-seedtool-cli 0.7.1:";;
    esac
   cat <<\_ACEOF
 
@@ -1375,7 +1375,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-bc-seedtool-cli configure 0.7.0
+bc-seedtool-cli configure 0.7.1
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -1962,7 +1962,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by bc-seedtool-cli $as_me 0.7.0, which was
+It was created by bc-seedtool-cli $as_me 0.7.1, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -5048,7 +5048,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by bc-seedtool-cli $as_me 0.7.0, which was
+This file was extended by bc-seedtool-cli $as_me 0.7.1, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -5110,7 +5110,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-bc-seedtool-cli config.status 0.7.0
+bc-seedtool-cli config.status 0.7.1
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 

configure.ac

@@ -2,7 +2,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.69])
-AC_INIT([bc-seedtool-cli], [0.7.0])
+AC_INIT([bc-seedtool-cli], [0.7.1])
 AC_CONFIG_SRCDIR([src/seedtool.cpp])
 AC_CONFIG_HEADERS([src/config.h])
 

src/format-bip39.cpp

@@ -29,7 +29,7 @@ void FormatBIP39::process_input(Params* p) {
     string input;
 
     if(p->is_ur_in) {
-        auto& ur = *(p->ur);
+        auto& ur = p->ur_shares.front();
         auto pos = ur.cbor().begin();
         const auto end = ur.cbor().end();
 

src/format-hex.cpp

@@ -25,7 +25,7 @@ void FormatHex::process_input(Params* p) {
     // ONLY in "raw entropy" mode.
 
     if(p->is_ur_in) {
-        auto& ur = *p->ur;
+        auto& ur = p->ur_shares.front();
         auto pos = ur.cbor().begin();
         const auto end = ur.cbor().end();
 

src/format-slip39.cpp

@@ -69,18 +69,19 @@ static byte_vector combine(string_vector shares) {
 
 void FormatSLIP39::process_input(Params* p) {
     if(p->is_ur_in) {
-        auto& ur = *p->ur;
-        auto pos = ur.cbor().begin();
-        const auto end = ur.cbor().end();
-
-        vector<string_vector> array_of_string_arrays;
-        typedef ur::ByteVector::const_iterator Iter;
-        auto f = [&array_of_string_arrays](Iter& pos, Iter end) {
-            decode_array_of_string_arrays(pos, end, array_of_string_arrays);
-        };
-        decode_dict_with_birthdate(pos, end, f);
-        for(auto a: array_of_string_arrays) {
-            p->shares.push_back(join(a, " "));
+        for(auto& ur: p->ur_shares) {
+            auto pos = ur.cbor().begin();
+            const auto end = ur.cbor().end();
+
+            vector<string_vector> array_of_string_arrays;
+            typedef ur::ByteVector::const_iterator Iter;
+            auto f = [&array_of_string_arrays](Iter& pos, Iter end) {
+                decode_array_of_string_arrays(pos, end, array_of_string_arrays);
+            };
+            decode_dict_with_birthdate(pos, end, f);
+            for(auto a: array_of_string_arrays) {
+                p->shares.push_back(join(a, " "));
+            }
         }
     } else {
         p->shares = p->get_multiple_arguments();

src/params.cpp

@@ -252,22 +252,73 @@ void Params::validate_input() {
             argp_error(state, "No input provided.");
         }
 
+        // We have to handle the cases of multi-part URs and multi-share URs, like SLIP39.
+        // It's also possible that SLIP39 UR shares might themselves be multi-part.
         if(is_ur_in) {
-            auto decoder = ur::URDecoder();
-            for(auto part: input) {
-                decoder.receive_part(part);
+            auto i = input.begin();
+            ur::URDecoder* decoder = NULL;
+
+            enum decoding_state {
+                starting,
+                decoding_multi_part,
+                decoding_multi_share
+            };
+
+            decoding_state ur_state = starting;
+
+            while(i != input.end()) {
+                auto part = *i;
+                //cout << part << endl;
+
+                if(decoder == NULL) {
+                    decoder = new ur::URDecoder();
+                }
+
+                decoder->receive_part(part);
+
+                if(decoder->is_failure()) {
+                    argp_error(state, "%s", decoder->result_error().what());
+                }
+
+                if(ur_state == starting) {
+                    if(decoder->is_success()) {
+                        ur_state = decoding_multi_share;
+                    } else {
+                        ur_state = decoding_multi_part;
+                    }
+                }
+
+                if(decoder->is_success()) {
+                    ur_shares.push_back(decoder->result_ur());
+                }
+
+                if(ur_state == decoding_multi_share) {
+                    if(decoder->is_success()) {
+                        delete decoder;
+                        decoder = NULL;
+                    } else {
+                        argp_error(state, "Multi-part UR encountered while decoding multi-share.");
+                    }
+                } else if(ur_state == decoding_multi_part) {
+                    if(decoder->is_success()) {
+                        delete decoder;
+                        decoder = NULL;
+                        break;
+                    }
+                }
+
+                i++;
             }
-            if(!decoder.is_complete()) {
+
+            if(decoder != NULL) {
                 argp_error(state, "Incomplete UR parts.");
-            } else if(decoder.is_failure()) {
-                argp_error(state, "%s", decoder.result_error().what());
             } else {
-                ur = decoder.result_ur();
-                if(ur->type() == "crypto-seed") {
+                auto type = ur_shares.front().type();
+                if(type == "crypto-seed") {
                     input_format = new FormatHex();
-                } else if(ur->type() == "crypto-bip39") {
+                } else if(type == "crypto-bip39") {
                     input_format = new FormatBIP39();
-                } else if(ur->type() == "crypto-slip39") {
+                } else if(type == "crypto-slip39") {
                     input_format = new FormatSLIP39();
                 } else {
                     argp_error(state, "Unknown UR type.");

src/params.hpp

@@ -55,7 +55,7 @@ class Params {
 
     bool is_ur_out = false;
     bool is_ur_in = false;
-    std::optional<ur::UR> ur;
+    std::vector<ur::UR> ur_shares;
     size_t max_fragment_length = 0;
     std::optional<size_t> fountain_parts;