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Merge pull request #24019 from yuwata/network-ipv4ll

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network: refuse 169.254.0.0/24 and 169.254.255.0/24
This commit is contained in:
Yu Watanabe 2022-07-15 07:59:13 +09:00 committed by GitHub
commit 3f5ef8aeac
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7 changed files with 28 additions and 21 deletions
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11
man/systemd.network.xml
View File

@ -401,12 +401,11 @@
<varlistentry>
<term><varname>IPv4LLStartAddress=</varname></term>
<listitem>
<para>Specifies the first IPv4 link-local address to try. Takes an IPv4 address
for example 169.254.1.2, from the link-local address range 169.254.0.0/16.
This setting may be useful if the device should always have the same address
as long as there is no address conflict. When unset, a random address will be automatically selected.
Defaults to unset.
</para>
<para>Specifies the first IPv4 link-local address to try. Takes an IPv4 address for example
169.254.1.2, from the link-local address range: 169.254.0.0/16 except for 169.254.0.0/24 and
169.254.255.0/24. This setting may be useful if the device should always have the same address
as long as there is no address conflict. When unset, a random address will be automatically
selected. Defaults to unset.</para>
</listitem>
</varlistentry>

14
src/basic/in-addr-util.c
View File

@ -49,6 +49,20 @@ bool in4_addr_is_link_local(const struct in_addr *a) {
return (be32toh(a->s_addr) & UINT32_C(0xFFFF0000)) == (UINT32_C(169) << 24 | UINT32_C(254) << 16);
}
bool in4_addr_is_link_local_dynamic(const struct in_addr *a) {
assert(a);
if (!in4_addr_is_link_local(a))
return false;
/* 169.254.0.0/24 and 169.254.255.0/24 must not be used for the dynamic IPv4LL assignment.
* See RFC 3927 Section 2.1:
* The IPv4 prefix 169.254/16 is registered with the IANA for this purpose. The first 256 and last
* 256 addresses in the 169.254/16 prefix are reserved for future use and MUST NOT be selected by a
* host using this dynamic configuration mechanism. */
return !IN_SET(be32toh(a->s_addr) & 0x0000FF00U, 0x0000U, 0xFF00U);
}
bool in6_addr_is_link_local(const struct in6_addr *a) {
assert(a);

1
src/basic/in-addr-util.h
View File

@ -44,6 +44,7 @@ static inline bool in_addr_data_is_set(const struct in_addr_data *a) {
int in_addr_is_multicast(int family, const union in_addr_union *u);
bool in4_addr_is_link_local(const struct in_addr *a);
bool in4_addr_is_link_local_dynamic(const struct in_addr *a);
bool in6_addr_is_link_local(const struct in6_addr *a);
int in_addr_is_link_local(int family, const union in_addr_union *u);
bool in6_addr_is_link_local_all_nodes(const struct in6_addr *a);

11
src/libsystemd-network/sd-ipv4ll.c
View File

@ -212,21 +212,12 @@ int sd_ipv4ll_is_running(sd_ipv4ll *ll) {
return sd_ipv4acd_is_running(ll->acd);
}
static bool ipv4ll_address_is_valid(const struct in_addr *address) {
assert(address);
if (!in4_addr_is_link_local(address))
return false;
return !IN_SET(be32toh(address->s_addr) & 0x0000FF00U, 0x0000U, 0xFF00U);
}
int sd_ipv4ll_set_address(sd_ipv4ll *ll, const struct in_addr *address) {
int r;
assert_return(ll, -EINVAL);
assert_return(address, -EINVAL);
assert_return(ipv4ll_address_is_valid(address), -EINVAL);
assert_return(in4_addr_is_link_local_dynamic(address), -EINVAL);
r = sd_ipv4acd_set_address(ll->acd, address);
if (r < 0)

5
src/network/networkd-ipv4ll.c
View File

@ -295,9 +295,10 @@ int config_parse_ipv4ll_address(
"Failed to parse %s=, ignoring assignment: %s", lvalue, rvalue);
return 0;
}
if (!in4_addr_is_link_local(&a.in)) {
if (!in4_addr_is_link_local_dynamic(&a.in)) {
log_syntax(unit, LOG_WARNING, filename, line, 0,
"Not a IPv4 link local address, ignoring assignment: %s", rvalue);
"Specified address cannot be used as an IPv4 link local address, ignoring assignment: %s",
rvalue);
return 0;
}

1
test/test-network/conf/25-dhcp-client-with-ipv4ll.network
View File

@ -6,3 +6,4 @@ Name=veth99
DHCP=ipv4
LinkLocalAddressing=yes
IPv6AcceptRA=no
IPv4LLStartAddress=169.254.133.11

6
test/test-network/systemd-networkd-tests.py
View File

@ -4570,7 +4570,7 @@ class NetworkdDHCPClientTests(unittest.TestCase, Utilities):
output = check_output('ip -4 address show dev veth99')
print(output)
self.assertNotIn('192.168.5.', output)
self.assertRegex(output, r'inet 169\.254\.\d+\.\d+/16 metric 2048 brd 169\.254\.255\.255 scope link')
self.assertIn('inet 169.254.133.11/16 metric 2048 brd 169.254.255.255 scope link', output)
start_dnsmasq()
print('Wait for a DHCP lease to be acquired and the IPv4LL address to be dropped')
@ -4587,12 +4587,12 @@ class NetworkdDHCPClientTests(unittest.TestCase, Utilities):
stop_dnsmasq()
print('Wait for the DHCP lease to be expired and an IPv4LL address to be acquired')
self.wait_address_dropped('veth99', r'inet 192\.168\.5\.\d+/24 metric 1024 brd 192\.168\.5\.255 scope global dynamic', ipv='-4', timeout_sec=130)
self.wait_address('veth99', r'inet 169\.254\.\d+\.\d+/16 metric 2048 brd 169\.254\.255\.255 scope link', scope='link', ipv='-4')
self.wait_address('veth99', r'inet 169\.254\.133\.11/16 metric 2048 brd 169\.254\.255\.255 scope link', scope='link', ipv='-4')
output = check_output('ip -4 address show dev veth99')
print(output)
self.assertNotIn('192.168.5.', output)
self.assertRegex(output, r'inet 169\.254\.\d+\.\d+/16 metric 2048 brd 169\.254\.255\.255 scope link')
self.assertIn('inet 169.254.133.11/16 metric 2048 brd 169.254.255.255 scope link', output)
def test_dhcp_client_use_dns(self):
def check(self, ipv4, ipv6):