From 1bb47b6796c7a2cfb64e6cdff37c43c03c473a81 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Sun, 26 Nov 2017 21:27:29 +0100
Subject: reverse: reject too-long symlink target reads with ENAMETOOLONG

If the symlink target gets too long due to base64 encoding, we should
return ENAMETOOLONG instead of having the kernel reject the data and
returning an I/O error to the user.

Fixes https://github.com/rfjakob/gocryptfs/issues/167
---
 tests/reverse/correctness_test.go | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

(limited to 'tests/reverse')

diff --git a/tests/reverse/correctness_test.go b/tests/reverse/correctness_test.go
index ee0a5b0..63043b7 100644
--- a/tests/reverse/correctness_test.go
+++ b/tests/reverse/correctness_test.go
@@ -147,3 +147,25 @@ func TestEnoent(t *testing.T) {
 		t.Errorf("want ENOENT, got: %v", err)
 	}
 }
+
+// If the symlink target gets too long due to base64 encoding, we should
+// return ENAMETOOLONG instead of having the kernel reject the data and
+// returning an I/O error to the user.
+// https://github.com/rfjakob/gocryptfs/issues/167
+func TestTooLongSymlink(t *testing.T) {
+	fn := dirA + "/TooLongSymlink"
+	target := string(bytes.Repeat([]byte("x"), 4000))
+	err := os.Symlink(target, fn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = os.Readlink(dirC + "/TooLongSymlink")
+	if err == nil {
+		return
+	}
+	err2 := err.(*os.PathError)
+	if err2.Err != syscall.ENAMETOOLONG {
+		t.Errorf("Expected %q error, got %q instead", syscall.ENAMETOOLONG,
+			err2.Err)
+	}
+}
-- 
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