From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sun, 16 Apr 2023 20:19:07 +0000 (+0900)
Subject: chase: make the result absolute when a symlink is absolute
X-Git-Tag: v254-rc1~681^2~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=24be89ebd8e9fbf97cb60c304b615ab26869c204;p=thirdparty%2Fsystemd.git

chase: make the result absolute when a symlink is absolute

As the path may be outside of the specified dir_fd.
---

diff --git a/src/basic/chase.c b/src/basic/chase.c
index a6a37978e8f..2b8befc7f7b 100644
--- a/src/basic/chase.c
+++ b/src/basic/chase.c
@@ -374,6 +374,11 @@ int chaseat(int dir_fd, const char *path, ChaseFlags flags, char **ret_path, int
                                     unsafe_transition(&st_child, &st))
                                         return log_unsafe_transition(child, fd, path, flags);
 
+                                /* When CHASE_AT_RESOLVE_IN_ROOT is not set, now the chased path may be
+                                 * outside of the specified dir_fd. Let's make the result absolute. */
+                                if (!FLAGS_SET(flags, CHASE_AT_RESOLVE_IN_ROOT))
+                                        need_absolute = true;
+
                                 r = free_and_strdup(&done, need_absolute ? "/" : NULL);
                                 if (r < 0)
                                         return r;
diff --git a/src/test/test-chase.c b/src/test/test-chase.c
index 52ea21a54c6..c5fc08ca25a 100644
--- a/src/test/test-chase.c
+++ b/src/test/test-chase.c
@@ -457,7 +457,16 @@ TEST(chaseat) {
 
         fd = safe_close(fd);
 
-        /* If the file descriptor does not point to the root directory, the result will be relative. */
+        /* If the file descriptor does not point to the root directory, the result will be relative
+         * unless the result is outside of the specified file descriptor. */
+
+        assert_se(chaseat(tfd, "abc", 0, &result, NULL) >= 0);
+        assert_se(streq(result, "/usr"));
+        result = mfree(result);
+
+        assert_se(chaseat(tfd, "/abc", 0, &result, NULL) >= 0);
+        assert_se(streq(result, "/usr"));
+        result = mfree(result);
 
         assert_se(chaseat(tfd, "abc", CHASE_AT_RESOLVE_IN_ROOT, NULL, NULL) == -ENOENT);
         assert_se(chaseat(tfd, "/abc", CHASE_AT_RESOLVE_IN_ROOT, NULL, NULL) == -ENOENT);