From: Daan De Meyer <daan.j.demeyer@gmail.com>
Date: Thu, 6 Jun 2024 20:59:36 +0000 (+0200)
Subject: chase: Tighten "." and "./" check
X-Git-Tag: v256~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7efaab482af44e0ffcb5242d4f37cc316e705e2d;p=thirdparty%2Fsystemd.git

chase: Tighten "." and "./" check

Currently the check also succeeds if the input path starts with a dot, whereas
we only want it to succeed for "." and "./". Tighten the check and add a test.
---

diff --git a/src/basic/chase.c b/src/basic/chase.c
index 245dd0800ef..4576e4b0588 100644
--- a/src/basic/chase.c
+++ b/src/basic/chase.c
@@ -641,8 +641,8 @@ int chase(const char *path, const char *root, ChaseFlags flags, char **ret_path,
                          * absolute, hence it is not necessary to prefix with the root. When "root" points to
                          * a non-root directory, the result path is always normalized and relative, hence
                          * we can simply call path_join() and not necessary to call path_simplify().
-                         * Note that the result of chaseat() may start with "." (more specifically, it may be
-                         * "." or "./"), and we need to drop "." in that case. */
+                         * As a special case, chaseat() may return "." or "./", which are normalized too,
+                         * but we need to drop "." before merging with root. */
 
                         if (empty_or_root(root))
                                 assert(path_is_absolute(p));
@@ -651,7 +651,7 @@ int chase(const char *path, const char *root, ChaseFlags flags, char **ret_path,
 
                                 assert(!path_is_absolute(p));
 
-                                q = path_join(root, p + (*p == '.'));
+                                q = path_join(root, p + STR_IN_SET(p, ".", "./"));
                                 if (!q)
                                         return -ENOMEM;
 
diff --git a/src/test/test-chase.c b/src/test/test-chase.c
index 5d3ee7aceec..13ee7028c87 100644
--- a/src/test/test-chase.c
+++ b/src/test/test-chase.c
@@ -236,6 +236,12 @@ TEST(chase) {
         ASSERT_STREQ(result, "/test-chase.fsldajfl");
         result = mfree(result);
 
+        r = chase("/.path/with/dot", temp, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &result, NULL);
+        ASSERT_OK(r);
+        q = strjoina(temp, "/.path/with/dot");
+        ASSERT_STREQ(result, q);
+        result = mfree(result);
+
         r = chase("/etc/machine-id/foo", NULL, 0, &result, NULL);
         assert_se(IN_SET(r, -ENOTDIR, -ENOENT));
         result = mfree(result);