diff --git a/src/basic/path-util.c b/src/basic/path-util.c index 80fdda170f..6c06bd2acb 100644 --- a/src/basic/path-util.c +++ b/src/basic/path-util.c @@ -131,8 +131,7 @@ int path_make_relative(const char *from_dir, const char *to_path, char **_r) { /* Skip the common part. */ for (;;) { - size_t a; - size_t b; + size_t a, b; from_dir += strspn(from_dir, "/"); to_path += strspn(to_path, "/"); @@ -144,7 +143,6 @@ int path_make_relative(const char *from_dir, const char *to_path, char **_r) { else /* from_dir is a parent directory of to_path. */ r = strdup(to_path); - if (!r) return -ENOMEM; @@ -175,21 +173,32 @@ int path_make_relative(const char *from_dir, const char *to_path, char **_r) { /* Count the number of necessary ".." elements. */ for (n_parents = 0;;) { + size_t w; + from_dir += strspn(from_dir, "/"); if (!*from_dir) break; - from_dir += strcspn(from_dir, "/"); - n_parents++; + w = strcspn(from_dir, "/"); + + /* If this includes ".." we can't do a simple series of "..", refuse */ + if (w == 2 && from_dir[0] == '.' && from_dir[1] == '.') + return -EINVAL; + + /* Count number of elements, except if they are "." */ + if (w != 1 || from_dir[0] != '.') + n_parents++; + + from_dir += w; } - r = malloc(n_parents * 3 + strlen(to_path) + 1); + r = new(char, n_parents * 3 + strlen(to_path) + 1); if (!r) return -ENOMEM; - for (p = r; n_parents > 0; n_parents--, p += 3) - memcpy(p, "../", 3); + for (p = r; n_parents > 0; n_parents--) + p = mempcpy(p, "../", 3); strcpy(p, to_path); path_kill_slashes(r); diff --git a/src/test/test-path-util.c b/src/test/test-path-util.c index e708d6ee50..ff46a896b5 100644 --- a/src/test/test-path-util.c +++ b/src/test/test-path-util.c @@ -261,6 +261,7 @@ static void test_make_relative(void) { assert_se(path_make_relative("some/relative/path", "/some/path", &result) < 0); assert_se(path_make_relative("/some/path", "some/relative/path", &result) < 0); + assert_se(path_make_relative("/some/dotdot/../path", "/some/path", &result) < 0); #define test(from_dir, to_path, expected) { \ _cleanup_free_ char *z = NULL; \ @@ -274,6 +275,7 @@ static void test_make_relative(void) { test("/some/path", "/some/path/in/subdir", "in/subdir"); test("/some/path", "/", "../.."); test("/some/path", "/some/other/path", "../other/path"); + test("/some/path/./dot", "/some/further/path", "../../further/path"); test("//extra/////slashes///won't////fool///anybody//", "////extra///slashes////are/just///fine///", "../../../are/just/fine"); }