1 files changed, 82 insertions, 0 deletions
diff --git a/t/t4254-am-corrupt.sh b/t/t4254-am-corrupt.sh
new file mode 100755
index 0000000000..daf01c309d
--- /dev/null
+++ b/t/t4254-am-corrupt.sh
@@ -0,0 +1,82 @@
+#!/bin/sh
+
+test_description='git am with corrupt input'
+. ./test-lib.sh
+
+make_mbox_with_nul () {
+	space=' '
+	q_nul_in_subject=
+	q_nul_in_body=
+	while test $# -ne 0
+	do
+		case "$1" in
+		subject) q_nul_in_subject='=00' ;;
+		body)    q_nul_in_body='=00' ;;
+		esac &&
+		shift
+	done &&
+	cat <<-EOF
+	From ec7364544f690c560304f5a5de9428ea3b978b26 Mon Sep 17 00:00:00 2001
+	From: A U Thor <author@example.com>
+	Date: Sun, 19 Apr 2020 13:42:07 +0700
+	Subject: [PATCH] =?ISO-8859-1?q?=C4=CB${q_nul_in_subject}=D1=CF=D6?=
+	MIME-Version: 1.0
+	Content-Type: text/plain; charset=ISO-8859-1
+	Content-Transfer-Encoding: quoted-printable
+
+	abc${q_nul_in_body}def
+	---
+	diff --git a/afile b/afile
+	new file mode 100644
+	index 0000000000..e69de29bb2
+	--$space
+	2.26.1
+	EOF
+}
+
+test_expect_success setup '
+	# Note the missing "+++" line:
+	cat >bad-patch.diff <<-\EOF &&
+	From: A U Thor <au.thor@example.com>
+	diff --git a/f b/f
+	index 7898192..6178079 100644
+	--- a/f
+	@@ -1 +1 @@
+	-a
+	+b
+	EOF
+
+	echo a >f &&
+	git add f &&
+	test_tick &&
+	git commit -m initial
+'
+
+# This used to fail before, too, but with a different diagnostic.
+#   fatal: unable to write file '(null)' mode 100644: Bad address
+# Also, it had the unwanted side-effect of deleting f.
+test_expect_success 'try to apply corrupted patch' '
+	test_when_finished "git am --abort" &&
+	test_must_fail git -c advice.amWorkDir=false am bad-patch.diff 2>actual &&
+	echo "error: git diff header lacks filename information (line 4)" >expected &&
+	test_path_is_file f &&
+	test_i18ncmp expected actual
+'
+
+test_expect_success "NUL in commit message's body" '
+	test_when_finished "git am --abort" &&
+	make_mbox_with_nul body >body.patch &&
+	test_must_fail git am body.patch 2>err &&
+	grep "a NUL byte in commit log message not allowed" err
+'
+
+test_expect_success "NUL in commit message's header" "
+	test_when_finished 'git am --abort' &&
+	make_mbox_with_nul subject >subject.patch &&
+	test_must_fail git mailinfo msg patch <subject.patch 2>err &&
+	grep \"a NUL byte in 'Subject' is not allowed\" err &&
+	test_must_fail git am subject.patch 2>err &&
+	grep \"a NUL byte in 'Subject' is not allowed\" err
+"
+
+test_done