From 494ef1674334bfb3b4b574cb24d447bc4e7986ab Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sat, 10 Dec 2022 10:21:41 +0900
Subject: [PATCH 1/3] resolve: drop recursion in TXT field handling

Fixes #25683.
---
 src/resolve/resolved-dns-rr.c | 32 +++++++++++++-------------------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index a4ba6bdc6d..5f890f9509 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -1768,36 +1768,30 @@ int dns_resource_record_get_cname_target(DnsResourceKey *key, DnsResourceRecord
         return 0;
 }
 
-DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i) {
-        DnsTxtItem *n;
+DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *first) {
+        LIST_FOREACH(items, i, first)
+                free(i);
 
-        if (!i)
-                return NULL;
-
-        n = i->items_next;
-
-        free(i);
-        return dns_txt_item_free_all(n);
+        return NULL;
 }
 
 bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b) {
+        DnsTxtItem *bb = b;
 
         if (a == b)
                 return true;
 
-        if (!a != !b)
-                return false;
+        LIST_FOREACH(items, aa, a) {
+                if (!bb)
+                        return false;
 
-        if (!a)
-                return true;
+                if (memcmp_nn(aa->data, aa->length, bb->data, bb->length) != 0)
+                        return false;
 
-        if (a->length != b->length)
-                return false;
+                bb = bb->items_next;
+        }
 
-        if (memcmp(a->data, b->data, a->length) != 0)
-                return false;
-
-        return dns_txt_item_equal(a->items_next, b->items_next);
+        return !bb;
 }
 
 DnsTxtItem *dns_txt_item_copy(DnsTxtItem *first) {

From 14822ede9f2c25ab93d7fceaa5f044804d24cfe8 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sat, 10 Dec 2022 10:25:38 +0900
Subject: [PATCH 2/3] resolve: shorten code a bit

---
 src/resolve/resolved-dns-rr.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 5f890f9509..ce9cecf118 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -1801,10 +1801,8 @@ DnsTxtItem *dns_txt_item_copy(DnsTxtItem *first) {
                 DnsTxtItem *j;
 
                 j = memdup(i, offsetof(DnsTxtItem, data) + i->length + 1);
-                if (!j) {
-                        dns_txt_item_free_all(copy);
-                        return NULL;
-                }
+                if (!j)
+                        return dns_txt_item_free_all(copy);
 
                 LIST_INSERT_AFTER(items, copy, end, j);
                 end = j;

From 068ef623bd2b9c7b39f0a021f5182700c0133ff1 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Sat, 10 Dec 2022 10:25:53 +0900
Subject: [PATCH 3/3] resolve: add missing assertion

---
 src/resolve/resolved-dns-rr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index ce9cecf118..d3175b1b9d 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -1814,6 +1814,8 @@ DnsTxtItem *dns_txt_item_copy(DnsTxtItem *first) {
 int dns_txt_item_new_empty(DnsTxtItem **ret) {
         DnsTxtItem *i;
 
+        assert(ret);
+
         /* RFC 6763, section 6.1 suggests to treat
          * empty TXT RRs as equivalent to a TXT record
          * with a single empty string. */
@@ -1823,7 +1825,6 @@ int dns_txt_item_new_empty(DnsTxtItem **ret) {
                 return -ENOMEM;
 
         *ret = i;
-
         return 0;
 }