From 263d2ce49d2a92130be913536bdee4c9d268670a Mon Sep 17 00:00:00 2001
From: Patrick Crosby <patrick@keyba.se>
Date: Mon, 9 Mar 2020 14:29:50 -0500
Subject: [PATCH] Handle symlinks properly when zipping a directory (#22981)

---
 go/service/saltpack.go                   | 23 +++++++++++++++++++++--
 go/service/testdata/archive/symlink_to_2 |  1 +
 go/service/testdata/archive/symlink_to_a |  1 +
 3 files changed, 23 insertions(+), 2 deletions(-)
 create mode 120000 go/service/testdata/archive/symlink_to_2
 create mode 120000 go/service/testdata/archive/symlink_to_a

diff --git a/go/service/saltpack.go b/go/service/saltpack.go
index ec932ec05487..d5eca8f61663 100644
--- a/go/service/saltpack.go
+++ b/go/service/saltpack.go
@@ -917,9 +917,28 @@ func zipDir(directory string, prog *progress.ProgressWriter) io.ReadCloser {
 				return nil
 			}
 
+			if (info.Mode() & os.ModeSymlink) != 0 {
+				// figure out the destination of the link
+				dest, err := os.Readlink(path)
+				if err != nil {
+					return err
+				}
+				header.Name = stripped
+				zw, err := w.CreateHeader(header)
+				if err != nil {
+					return err
+				}
+				// the body of the entry is the link destination
+				_, err = zw.Write([]byte(dest))
+				if err != nil {
+					return err
+				}
+				return nil
+			}
+
 			// make a regular file and copy all the data into it.
 			header.Name = stripped
-			w, err := w.CreateHeader(header)
+			zw, err := w.CreateHeader(header)
 			if err != nil {
 				return err
 			}
@@ -929,7 +948,7 @@ func zipDir(directory string, prog *progress.ProgressWriter) io.ReadCloser {
 			}
 			defer f.Close()
 			tr := io.TeeReader(bufio.NewReader(f), prog)
-			_, err = io.Copy(w, tr)
+			_, err = io.Copy(zw, tr)
 			if err != nil {
 				return err
 			}
diff --git a/go/service/testdata/archive/symlink_to_2 b/go/service/testdata/archive/symlink_to_2
new file mode 120000
index 000000000000..d8263ee98605
--- /dev/null
+++ b/go/service/testdata/archive/symlink_to_2
@@ -0,0 +1 @@
+2
\ No newline at end of file
diff --git a/go/service/testdata/archive/symlink_to_a b/go/service/testdata/archive/symlink_to_a
new file mode 120000
index 000000000000..8d14cbf983b3
--- /dev/null
+++ b/go/service/testdata/archive/symlink_to_a
@@ -0,0 +1 @@
+a.txt
\ No newline at end of file