From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 22 Nov 2023 20:03:43 +0000 (+0900)
Subject: parse-util: accept arbitrary MTU size when AF_UNSPEC
X-Git-Tag: v256-rc1~1515^2~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a0460dfed617a73f7dbf36a6eb7e474e887ae780;p=thirdparty%2Fsystemd.git

parse-util: accept arbitrary MTU size when AF_UNSPEC

When [Link] MTU= is specified in a .network file, we have no idea about
that what kind of interface will be configured with the .network file.
The maximum and minimum MTU size depend on the kind of interface.
So, we should not filter MTU eagerly in the parser.

Closes #30140.
---

diff --git a/src/basic/parse-util.c b/src/basic/parse-util.c
index dc868c9b8e9..0430e33e40d 100644
--- a/src/basic/parse-util.c
+++ b/src/basic/parse-util.c
@@ -123,8 +123,7 @@ int parse_ifindex(const char *s) {
 }
 
 int parse_mtu(int family, const char *s, uint32_t *ret) {
-        uint64_t u;
-        size_t m;
+        uint64_t u, m;
         int r;
 
         r = parse_size(s, 1024, &u);
@@ -134,10 +133,16 @@ int parse_mtu(int family, const char *s, uint32_t *ret) {
         if (u > UINT32_MAX)
                 return -ERANGE;
 
-        if (family == AF_INET6)
+        switch (family) {
+        case AF_INET:
+                m = IPV4_MIN_MTU; /* This is 68 */
+                break;
+        case AF_INET6:
                 m = IPV6_MIN_MTU; /* This is 1280 */
-        else
-                m = IPV4_MIN_MTU; /* For all other protocols, including 'unspecified' we assume the IPv4 minimal MTU */
+                break;
+        default:
+                m = 0;
+        }
 
         if (u < m)
                 return -ERANGE;
diff --git a/src/test/test-parse-util.c b/src/test/test-parse-util.c
index 7a485f390fb..58d22b6cfee 100644
--- a/src/test/test-parse-util.c
+++ b/src/test/test-parse-util.c
@@ -914,15 +914,30 @@ TEST(parse_mtu) {
         assert_se(parse_mtu(AF_UNSPEC, "4294967295", &mtu) >= 0 && mtu == 4294967295);
         assert_se(parse_mtu(AF_UNSPEC, "500", &mtu) >= 0 && mtu == 500);
         assert_se(parse_mtu(AF_UNSPEC, "1280", &mtu) >= 0 && mtu == 1280);
+        assert_se(parse_mtu(AF_UNSPEC, "4294967296", &mtu) == -ERANGE);
+        assert_se(parse_mtu(AF_UNSPEC, "68", &mtu) >= 0 && mtu == 68);
+        assert_se(parse_mtu(AF_UNSPEC, "67", &mtu) >= 0 && mtu == 67);
+        assert_se(parse_mtu(AF_UNSPEC, "0", &mtu) >= 0 && mtu == 0);
+        assert_se(parse_mtu(AF_UNSPEC, "", &mtu) == -EINVAL);
+
+        assert_se(parse_mtu(AF_INET, "1500", &mtu) >= 0 && mtu == 1500);
+        assert_se(parse_mtu(AF_INET, "1400", &mtu) >= 0 && mtu == 1400);
+        assert_se(parse_mtu(AF_INET, "65535", &mtu) >= 0 && mtu == 65535);
+        assert_se(parse_mtu(AF_INET, "65536", &mtu) >= 0 && mtu == 65536);
+        assert_se(parse_mtu(AF_INET, "4294967295", &mtu) >= 0 && mtu == 4294967295);
+        assert_se(parse_mtu(AF_INET, "500", &mtu) >= 0 && mtu == 500);
+        assert_se(parse_mtu(AF_INET, "1280", &mtu) >= 0 && mtu == 1280);
+        assert_se(parse_mtu(AF_INET, "4294967296", &mtu) == -ERANGE);
+        assert_se(parse_mtu(AF_INET, "68", &mtu) >= 0 && mtu == 68);
+        assert_se(parse_mtu(AF_INET, "67", &mtu) == -ERANGE);
+        assert_se(parse_mtu(AF_INET, "0", &mtu) == -ERANGE);
+        assert_se(parse_mtu(AF_INET, "", &mtu) == -EINVAL);
+
         assert_se(parse_mtu(AF_INET6, "1280", &mtu) >= 0 && mtu == 1280);
         assert_se(parse_mtu(AF_INET6, "1279", &mtu) == -ERANGE);
-        assert_se(parse_mtu(AF_UNSPEC, "4294967296", &mtu) == -ERANGE);
         assert_se(parse_mtu(AF_INET6, "4294967296", &mtu) == -ERANGE);
         assert_se(parse_mtu(AF_INET6, "68", &mtu) == -ERANGE);
-        assert_se(parse_mtu(AF_UNSPEC, "68", &mtu) >= 0 && mtu == 68);
-        assert_se(parse_mtu(AF_UNSPEC, "67", &mtu) == -ERANGE);
-        assert_se(parse_mtu(AF_UNSPEC, "0", &mtu) == -ERANGE);
-        assert_se(parse_mtu(AF_UNSPEC, "", &mtu) == -EINVAL);
+        assert_se(parse_mtu(AF_INET6, "", &mtu) == -EINVAL);
 }
 
 TEST(parse_loadavg_fixed_point) {
diff --git a/test/test-network-generator-conversion.sh b/test/test-network-generator-conversion.sh
index 6224a4d04f9..9a4732c981d 100755
--- a/test/test-network-generator-conversion.sh
+++ b/test/test-network-generator-conversion.sh
@@ -296,7 +296,7 @@ INVALID_COMMAND_LINES=(
     "ip=10.0.0.1:::255.255.255::foo99:off"
     "ip=10.0.0.1:::255.255.255.0:invalid_hostname:foo99:off"
     "ip=10.0.0.1:::255.255.255.0::verylonginterfacename:off"
-    "ip=:::::dhcp99:dhcp6:0"
+    "ip=:::::dhcp99:dhcp6:4294967296"
     "ip=:::::dhcp99:dhcp6:-1"
     "ip=:::::dhcp99:dhcp6:666:52:54:00"
     "ip=fdef:c400:bd01:1096::2::[fdef:c400:bd01:1096::1]:64::ipv6:off:[fdef:c400:bd01:1096::aaaa]"