From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Thu, 20 Jul 2023 06:17:27 +0000 (+0900)
Subject: chase: carefully handle result of extracting parent directory
X-Git-Tag: v255-rc1~875^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4de5b4e3751609e6a0fe5e3f5dfef22ccae56fad;p=thirdparty%2Fsystemd.git

chase: carefully handle result of extracting parent directory

Should not change any behavior.
---

diff --git a/src/basic/chase.c b/src/basic/chase.c
index 4d883e18d8e..b612a2fef61 100644
--- a/src/basic/chase.c
+++ b/src/basic/chase.c
@@ -292,9 +292,25 @@ int chaseat(int dir_fd, const char *path, ChaseFlags flags, char **ret_path, int
                         }
 
                         r = path_extract_directory(done, &parent);
-                        if (r >= 0 || r == -EDESTADDRREQ)
+                        if (r >= 0) {
+                                assert(!need_absolute || path_is_absolute(parent));
                                 free_and_replace(done, parent);
-                        else if (IN_SET(r, -EINVAL, -EADDRNOTAVAIL)) {
+                        } else if (r == -EDESTADDRREQ) {
+                                /* 'done' contains filename only (i.e. no slash). */
+                                assert(!need_absolute);
+                                done = mfree(done);
+                        } else if (r == -EADDRNOTAVAIL) {
+                                /* 'done' is "/". This branch should be already handled in the above. */
+                                assert(!FLAGS_SET(flags, CHASE_AT_RESOLVE_IN_ROOT));
+                                assert_not_reached();
+                        } else if (r == -EINVAL) {
+                                /* 'done' is an empty string, ends with '..', or an invalid path. */
+                                assert(!need_absolute);
+                                assert(!FLAGS_SET(flags, CHASE_AT_RESOLVE_IN_ROOT));
+
+                                if (!path_is_valid(done))
+                                        return -EINVAL;
+
                                 /* If we're at the top of "dir_fd", start appending ".." to "done". */
                                 if (!path_extend(&done, ".."))
                                         return -ENOMEM;