From 6af44f8432fe07c0ce1feba885399be3511b8a73 Mon Sep 17 00:00:00 2001
From: Luiz Aoqui <luiz@hashicorp.com>
Date: Fri, 9 Apr 2021 14:37:27 -0400
Subject: [PATCH] limit bytes passed to http.DetectContentType (#10348)

---
 client/allocdir/alloc_dir.go      | 4 ++--
 client/allocdir/alloc_dir_test.go | 1 +
 client/allocdir/input/test.hcl    | 3 +++
 3 files changed, 6 insertions(+), 2 deletions(-)
 create mode 100644 client/allocdir/input/test.hcl

diff --git a/client/allocdir/alloc_dir.go b/client/allocdir/alloc_dir.go
index a51ba5c34a13..bd16f1d59bb9 100644
--- a/client/allocdir/alloc_dir.go
+++ b/client/allocdir/alloc_dir.go
@@ -426,9 +426,9 @@ func detectContentType(fileInfo os.FileInfo, path string) string {
 		// We ignore errors because this is optional information
 		if err == nil {
 			fileBytes := make([]byte, 512)
-			_, err := f.Read(fileBytes)
+			n, err := f.Read(fileBytes)
 			if err == nil {
-				contentType = http.DetectContentType(fileBytes)
+				contentType = http.DetectContentType(fileBytes[:n])
 			}
 			f.Close()
 		}
diff --git a/client/allocdir/alloc_dir_test.go b/client/allocdir/alloc_dir_test.go
index 82b3ae1cb13b..8dc61b5cd622 100644
--- a/client/allocdir/alloc_dir_test.go
+++ b/client/allocdir/alloc_dir_test.go
@@ -493,6 +493,7 @@ func TestAllocDir_DetectContentType(t *testing.T) {
 		"input/test.json": "application/json",
 		"input/test.txt":  "text/plain; charset=utf-8",
 		"input/test.go":   "text/plain; charset=utf-8",
+		"input/test.hcl":  "text/plain; charset=utf-8",
 	}
 	for _, file := range testFiles {
 		fileInfo, err := os.Stat(file)
diff --git a/client/allocdir/input/test.hcl b/client/allocdir/input/test.hcl
new file mode 100644
index 000000000000..64aa42c4da13
--- /dev/null
+++ b/client/allocdir/input/test.hcl
@@ -0,0 +1,3 @@
+test "test" {
+  test = "test"
+}