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>

diff --git a/mailmap.c b/mailmap.c
index eb77c6e77cebf517c989cb0a072e9ead77fd6350..7ac966107ebab7fab8ad25fbc32d8e8f78a7c31c 100644 (file)
--- a/mailmap.c
+++ b/mailmap.c
@@ -157,20 +157,30 @@ static void read_mailmap_line(struct string_list *map, char *buffer)
                add_mapping(map, name1, email1, name2, email2);
 }
 
-static int read_mailmap_file(struct string_list *map, const char *filename)
+/* Flags for read_mailmap_file() */
+#define MAILMAP_NOFOLLOW (1<<0)
+
+static int read_mailmap_file(struct string_list *map, const char *filename,
+                            unsigned flags)
 {
        char buffer[1024];
        FILE *f;
+       int fd;
 
        if (!filename)
                return 0;
 
-       f = fopen(filename, "r");
-       if (!f) {
+       if (flags & MAILMAP_NOFOLLOW)
+               fd = open_nofollow(filename, O_RDONLY);
+       else
+               fd = open(filename, O_RDONLY);
+
+       if (fd < 0) {
                if (errno == ENOENT)
                        return 0;
                return error_errno("unable to open mailmap at %s", filename);
        }
+       f = xfdopen(fd, "r");
 
        while (fgets(buffer, sizeof(buffer), f) != NULL)
                read_mailmap_line(map, buffer);
@@ -225,10 +235,12 @@ int read_mailmap(struct string_list *map)
        if (!git_mailmap_blob && is_bare_repository())
                git_mailmap_blob = "HEAD:.mailmap";
 
-       err |= read_mailmap_file(map, ".mailmap");
+       err |= read_mailmap_file(map, ".mailmap",
+                                startup_info->have_repository ?
+                                MAILMAP_NOFOLLOW : 0);
        if (startup_info->have_repository)
                err |= read_mailmap_blob(map, git_mailmap_blob);
-       err |= read_mailmap_file(map, git_mailmap_file);
+       err |= read_mailmap_file(map, git_mailmap_file, 0);
        return err;
 }
 

diff --git a/t/t4203-mailmap.sh b/t/t4203-mailmap.sh
index 621f9962d51ea862af3692d2a9fd3fc358bbab0f..96a4e6132f082997b9e0e92da492765a3d636cda 100755 (executable)
--- 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