mailmap: do not respect symlinks for in-tree .mailmap

As with .gitattributes and .gitignore, we would like to make sure that
.mailmap files are handled consistently whether read from the a blob (as
is the default behavior in a bare repo) or from the filesystem.
Likewise, we would like to avoid reading out-of-tree files pointed to by
a symlink, which could have security implications in certain setups.

We can cover both by using open_nofollow() when opening the in-tree
files. We'll continue to follow links for mailmap.file, as well as when
reading .mailmap from the current directory when outside of a repository
entirely.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/t/t4203-mailmap.sh b/t/t4203-mailmap.sh
index 621f9962d5..96a4e6132f 100755
--- a/t/t4203-mailmap.sh
+++ b/t/t4203-mailmap.sh
@@ -889,4 +889,35 @@ test_expect_success 'empty syntax: setup' '
 	test_cmp expect actual
 '
 
+test_expect_success SYMLINKS 'set up symlink tests' '
+	git commit --allow-empty -m foo --author="Orig <orig@example.com>" &&
+	echo "New <new@example.com> <orig@example.com>" >map &&
+	rm -f .mailmap
+'
+
+test_expect_success SYMLINKS 'symlinks respected in mailmap.file' '
+	test_when_finished "rm symlink" &&
+	ln -s map symlink &&
+	git -c mailmap.file="$(pwd)/symlink" log -1 --format=%aE >actual &&
+	echo "new@example.com" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success SYMLINKS 'symlinks respected in non-repo shortlog' '
+	git log -1 >input &&
+	test_when_finished "nongit rm .mailmap" &&
+	nongit ln -sf "$TRASH_DIRECTORY/map" .mailmap &&
+	nongit git shortlog -s <input >actual &&
+	echo "     1	New" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success SYMLINKS 'symlinks not respected in-tree' '
+	test_when_finished "rm .mailmap" &&
+	ln -s map .mailmap &&
+	git log -1 --format=%aE >actual &&
+	echo "orig@example.com" >expect&&
+	test_cmp expect actual
+'
+
 test_done