From 9f497717cbb7ffea60b235da3e10a7b42bda41ac Mon Sep 17 00:00:00 2001
From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Sat, 9 Feb 2019 14:57:46 +0000
Subject: [PATCH] JSON: fix crashes in ${extract jsons } and ${extract json
 {digits} }

Broken-by: 386ab6457b and 8fdf20fd84
---
 src/src/expand.c             | 27 +++++++++++++++------------
 test/scripts/0000-Basic/0002 |  4 ++++
 test/stdout/0002             |  4 ++++
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/src/expand.c b/src/src/expand.c
index ec5660adb..aa4d0289e 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -5811,10 +5811,11 @@ while (*s != 0)
 	      }
 	    while (field_number > 0 && (item = json_nextinlist(&list)))
 	      field_number--;
-	    s = item;
-	    lookup_value = s;
-	    while (*s) s++;
-	    while (--s >= lookup_value && isspace(*s)) *s = '\0';
+	    if ((lookup_value = s = item))
+	      {
+	      while (*s) s++;
+	      while (--s >= lookup_value && isspace(*s)) *s = '\0';
+	      }
 	    }
 	  else
 	    {
@@ -5850,14 +5851,16 @@ while (*s != 0)
 	    }
 	  }
 
-	  if (fmt == extract_jsons)
-	    if (!(lookup_value = dewrap(lookup_value, US"\"\"")))
-	      {
-	      expand_string_message =
-		string_sprintf("%s wrapping string result for extract jsons",
-		  expand_string_message);
-	      goto EXPAND_FAILED_CURLY;
-	      }
+	  if (  fmt == extract_jsons
+	     && lookup_value
+	     && !(lookup_value = dewrap(lookup_value, US"\"\"")))
+	    {
+	    expand_string_message =
+	      string_sprintf("%s wrapping string result for extract jsons",
+		expand_string_message);
+	    goto EXPAND_FAILED_CURLY;
+	    }
+	  break;	/* json/s */
 	}
 
       /* If no string follows, $value gets substituted; otherwise there can
diff --git a/test/scripts/0000-Basic/0002 b/test/scripts/0000-Basic/0002
index ad1910510..65ad69047 100644
--- a/test/scripts/0000-Basic/0002
+++ b/test/scripts/0000-Basic/0002
@@ -895,6 +895,8 @@ ${extract json {2} {${extract json{IDs} {\{"other":"foo", "IDs": [116, 943, 234]
 
 ${extract json {2} {["red", "green", "blue", "black"]} }
 ${extract jsons{2} {["red", "green", "blue", "black"]} }
+<${extract jsons{5} {["red", "green", "blue", "black"]} }>
+expect: <>
 
 ${extract json {seconds} { \{"hours":0, "mins":0, "seconds":59\} }}
 ${extract json {seconds} {${extract json {2} { ["irrelevant", \{"hours":0, "mins":0, "seconds":59\}] }}}}
@@ -907,6 +909,8 @@ expect: {"1":116, "2":943, "3":234}
 
 <${extract json{nonexistent}{ \{"id": \{"a":101, "b":102\}, "IDs": \{"1":116, "2":943, "3":234\}\} }}>
 expect: <>
+<${extract jsons{nonexistent}{ \{"id": \{"a":101, "b":102\}, "IDs": \{"1":116, "2":943, "3":234\}\} }}>
+expect: <>
 
 ${if forany_json {[1, 2, 3]}{={$item}{1}}{yes}{no}}
 ${if forany_jsons{["A", "B", "C"]}{eq{$item}{B}}{yes}{no}}
diff --git a/test/stdout/0002 b/test/stdout/0002
index f53d9d563..f5a97289a 100644
--- a/test/stdout/0002
+++ b/test/stdout/0002
@@ -838,6 +838,8 @@ xyz
 > 
 > "green"
 > green
+> <>
+> expect: <>
 > 
 > 59
 > 59
@@ -850,6 +852,8 @@ xyz
 > 
 > <>
 > expect: <>
+> <>
+> expect: <>
 > 
 > yes
 > yes
-- 
2.25.1