support non-standard DHCP Option 15 in EC2

packages/systemd/9013-sd-dhcp-lease-parse-multiple-domains-in-option-15.patch

@@ -0,0 +1,131 @@
+From 4c79d11d6888944f251681003a7b8b41606e108b Mon Sep 17 00:00:00 2001
+From: Ben Cressey <[email protected]>
+Date: Sat, 2 Sep 2023 16:19:22 +0000
+Subject: [PATCH] sd-dhcp-lease: parse multiple domains in option 15
+
+Non-compliant DHCP servers may pass through multiple domain names in
+Option 15, separated by a space character. This is then normalized
+into "032" by systemd-networkd, which effectively synthesizes a new
+domain name that doesn't match any of the expected ones.
+
+DHCP also supports Option 119 which specifies a compression scheme to
+avoid repeating any shared suffixes of the domain names. This option
+doesn't support space-separated domains either, so working around the
+problem isn't as straightforward as treating an Option 15 payload as
+a 119 payload instead.
+
+Deal with this by splitting the Option 15 payload on spaces first,
+before normalizing the individual domain names. If multiple domains
+are found, use them as the list of search domains unless Option 119
+is also present.
+
+Signed-off-by: Ben Cressey <[email protected]>
+---
+ src/libsystemd-network/sd-dhcp-lease.c | 69 +++++++++++++++++++++-----
+ 1 file changed, 56 insertions(+), 13 deletions(-)
+
+diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
+index b14ad57..263e97e 100644
+--- a/src/libsystemd-network/sd-dhcp-lease.c
++++ b/src/libsystemd-network/sd-dhcp-lease.c
+@@ -401,34 +401,70 @@ static int lease_parse_string(const uint8_t *option, size_t len, char **ret) {
+         return 0;
+ }
+
+-static int lease_parse_domain(const uint8_t *option, size_t len, char **ret) {
+-        _cleanup_free_ char *name = NULL, *normalized = NULL;
++static int lease_parse_domain_list(const uint8_t *option, size_t len, char ***ret) {
++        _cleanup_free_ char *parsed = NULL;
++        _cleanup_strv_free_ char **names = NULL, **normalized_names = NULL;
+         int r;
+
+         assert(option);
+         assert(ret);
+
+-        r = lease_parse_string(option, len, &name);
++        r = lease_parse_string(option, len, &parsed);
+         if (r < 0)
+                 return r;
+-        if (!name) {
+-                *ret = mfree(*ret);
++
++        if (!parsed)
+                 return 0;
++
++        names = strv_split(parsed, " ");
++        if (!names)
++                return -ENOMEM;
++
++        STRV_FOREACH(name, names) {
++                _cleanup_free_ char *normalized = NULL;
++
++                r = dns_name_normalize(*name, 0, &normalized);
++                if (r < 0)
++                        return r;
++
++                if (is_localhost(normalized))
++                        return -EINVAL;
++
++                if (dns_name_is_root(normalized))
++                        return -EINVAL;
++
++                r = strv_extend(&normalized_names, normalized);
++                if (r < 0)
++                        return r;
+         }
+
+-        r = dns_name_normalize(name, 0, &normalized);
++        strv_free_and_replace(*ret, normalized_names);
++        return 0;
++}
++
++static int lease_parse_domain(const uint8_t *option, size_t len, char **ret) {
++        _cleanup_strv_free_ char **names = NULL;
++        size_t n;
++        int r;
++
++        assert(option);
++        assert(ret);
++
++        r = lease_parse_domain_list(option, len, &names);
+         if (r < 0)
+                 return r;
+
+-        if (is_localhost(normalized))
+-                return -EINVAL;
+-
+-        if (dns_name_is_root(normalized))
+-                return -EINVAL;
++        n = strv_length(names);
++        if (n == 0) {
++                *ret = mfree(*ret);
++                return 0;
++        }
+
+-        free_and_replace(*ret, normalized);
++        r = free_and_strdup(ret, names[0]);
++        if (r < 0)
++                return r;
+
+-        return 0;
++        return n;
+ }
+
+ static int lease_parse_in_addrs(const uint8_t *option, size_t len, struct in_addr **ret, size_t *n_ret) {
+@@ -725,6 +761,13 @@ int dhcp_lease_parse_options(uint8_t code, uint8_t len, const void *option, void
+                         return 0;
+                 }
+
++                if (r <= 1 || !strv_isempty(lease->search_domains))
++                        break;
++
++                r = lease_parse_domain_list(option, len, &lease->search_domains);
++                if (r < 0)
++                        log_debug_errno(r, "Failed to parse Domain Search List, ignoring: %m");
++
+                 break;
+
+         case SD_DHCP_OPTION_DOMAIN_SEARCH:
+-- 
+2.40.1
+

packages/systemd/systemd.spec

@@ -57,6 +57,10 @@ Patch9011: 9011-systemd-networkd-Conditionalize-hostnamed-timezoned-.patch
 # as a kernel command line parameter to override.
 Patch9012: 9012-core-mount-increase-mount-rate-limit-burst-to-25.patch
 
+# Local patch to work around a potentially non-compliant Option 15 in the DHCP
+# lease in EC2.
+Patch9013: 9013-sd-dhcp-lease-parse-multiple-domains-in-option-15.patch
+
 BuildRequires: gperf
 BuildRequires: intltool
 BuildRequires: meson