From 71d6fa9ad07f42e20eadbad11844301caae1a187 Mon Sep 17 00:00:00 2001
From: Daniel Schultz <slifty@gmail.com>
Date: Fri, 4 Dec 2020 16:23:04 -0500
Subject: [PATCH] Fix dual-callback case (#3537)

This fixes a bug where using the callback version of createPresignedPost
without proper AWS credentials configured would result in an
un-catchable error and crash the node process.

It is not possible to write a test to capture this error due to the
nature of the error.  The callback is called, and only after that does
the crash occur.
---
 .changes/next-release/bugfix-S3-9d19dd09.json | 5 +++++
 lib/services/s3.js                            | 8 ++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 .changes/next-release/bugfix-S3-9d19dd09.json

diff --git a/.changes/next-release/bugfix-S3-9d19dd09.json b/.changes/next-release/bugfix-S3-9d19dd09.json
new file mode 100644
index 0000000000..6df9dae1eb
--- /dev/null
+++ b/.changes/next-release/bugfix-S3-9d19dd09.json
@@ -0,0 +1,5 @@
+{
+  "type": "bugfix",
+  "category": "S3",
+  "description": "fixed a bug where createPresignedPost could result in a process crash."
+}
\ No newline at end of file
diff --git a/lib/services/s3.js b/lib/services/s3.js
index 345f45ef51..ef2f991be8 100644
--- a/lib/services/s3.js
+++ b/lib/services/s3.js
@@ -1079,9 +1079,13 @@ AWS.util.update(AWS.S3.prototype, {
       config.getCredentials(function (err) {
         if (err) {
           callback(err);
+        } else {
+          try {
+            callback(null, finalizePost());
+          } catch (err) {
+            callback(err);
+          }
         }
-
-        callback(null, finalizePost());
       });
     } else {
       return finalizePost();