new file mode 100644
@@ -0,0 +1,295 @@
+From 5c8341ba6ff3a8e4e4dfd616f8ed0418838b8b7b Mon Sep 17 00:00:00 2001
+From: "c-ares-backport-gha[bot]"
+ <299594594+c-ares-backport-gha[bot]@users.noreply.github.com>
+Date: Sun, 5 Jul 2026 05:41:49 +0000
+Subject: [PATCH] [Backport v1.34] enforce 255 octet name limit when parsing
+ dns names (#1210)
+
+# Description
+Backport of #1164 to `v1.34`.
+
+Signed-off-by: Syed Mohammed Nayyar <jmestwa@gmail.com>
+Co-authored-by: jmestwa-coder <jmestwa@gmail.com>
+
+CVE: CVE-2026-69184
+Upstream-Status: Backport [https://github.com/c-ares/c-ares/commit/5c8341ba6ff3a8e4e4dfd616f8ed0418838b8b7b]
+Signed-off-by: Peter Marko <peter.marko@siemens.com>
+---
+ src/lib/ares_dns_name.c | 42 +++++++++-
+ test/ares-test-parse.cc | 176 ++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 216 insertions(+), 2 deletions(-)
+
+diff --git a/src/lib/ares_dns_name.c b/src/lib/ares_dns_name.c
+index b7fdf594..134f3edc 100644
+--- a/src/lib/ares_dns_name.c
++++ b/src/lib/ares_dns_name.c
+@@ -27,6 +27,18 @@
+ #include "ares.h"
+ #include "ares_private.h"
+
++/* RFC 1035 3.1 limits a name to 255 octets. We track presentation length
++ * (label octets plus one separator before each label after the first), which is
++ * up to ~2 octets looser than the strict wire limit and so never rejects a
++ * compliant name. Shared by the read and write paths. */
++#define ARES_MAX_NAME_PRESENTATION_LEN 255
++
++/* A name of <= 255 octets holds at most 128 labels, so it can never legitimately
++ * require more than that many compression-pointer jumps. Bounding the number of
++ * indirections stops a name built purely from pointers (which never adds label
++ * bytes, so the length cap never fires) from being walked without limit. */
++#define ARES_MAX_INDIRS 128
++
+ typedef struct {
+ char *name;
+ size_t name_len;
+@@ -50,7 +62,7 @@ static ares_status_t ares__nameoffset_create(ares__llist_t **list,
+ ares_nameoffset_t *off = NULL;
+
+ if (list == NULL || name == NULL || ares_strlen(name) == 0 ||
+- ares_strlen(name) > 255) {
++ ares_strlen(name) > ARES_MAX_NAME_PRESENTATION_LEN) {
+ return ARES_EFORMERR;
+ }
+
+@@ -341,7 +353,7 @@ static ares_status_t ares_split_dns_name(ares_dns_labels_t *labels,
+ }
+
+ /* Can't exceed maximum (unescaped) length */
+- if (labels->num && total_len + labels->num - 1 > 255) {
++ if (labels->num && total_len + labels->num - 1 > ARES_MAX_NAME_PRESENTATION_LEN) {
+ status = ARES_EBADNAME;
+ goto done;
+ }
+@@ -541,6 +553,8 @@ ares_status_t ares__dns_name_parse(ares__buf_t *buf, char **name,
+ ares_status_t status;
+ ares__buf_t *namebuf = NULL;
+ size_t label_start = ares__buf_get_position(buf);
++ size_t name_len = 0;
++ size_t indir = 0;
+
+ if (buf == NULL) {
+ return ARES_EFORMERR;
+@@ -612,6 +626,16 @@ ares_status_t ares__dns_name_parse(ares__buf_t *buf, char **name,
+ goto fail;
+ }
+
++ /* Bound the number of indirections. A name made purely of pointers never
++ * adds label bytes, so the length cap below can't stop it; the
++ * strictly-decreasing rule alone still allows thousands of jumps per name.
++ * No legitimate <= 255 octet name needs more than 128 labels/jumps. */
++ indir++;
++ if (indir > ARES_MAX_INDIRS) {
++ status = ARES_EBADNAME;
++ goto fail;
++ }
++
+ /* First time we make a jump, save the current position */
+ if (save_offset == 0) {
+ save_offset = ares__buf_get_position(buf);
+@@ -635,6 +659,20 @@ ares_status_t ares__dns_name_parse(ares__buf_t *buf, char **name,
+
+ /* New label */
+
++ /* RFC 1035 3.1 limits a name to 255 octets. Enforce it during
++ * decompression so labels reached through a chain of pointers can't expand a
++ * single name without bound. Track the presentation length (label data plus
++ * the separator that precedes each label after the first), matching
++ * ares_split_dns_name() on the write side. */
++ if (name_len) {
++ name_len++;
++ }
++ name_len += c;
++ if (name_len > ARES_MAX_NAME_PRESENTATION_LEN) {
++ status = ARES_EBADNAME;
++ goto fail;
++ }
++
+ /* Labels are separated by periods */
+ if (ares__buf_len(namebuf) != 0 && name != NULL) {
+ status = ares__buf_append_byte(namebuf, '.');
+diff --git a/test/ares-test-parse.cc b/test/ares-test-parse.cc
+index 81fd7deb..399c94dd 100644
+--- a/test/ares-test-parse.cc
++++ b/test/ares-test-parse.cc
+@@ -219,5 +219,181 @@ TEST_F(LibraryTest, ParseMalformedRRCount) {
+ EXPECT_EQ(nullptr, dnsrec);
+ }
+
++TEST_F(LibraryTest, ParseRejectsOverlongName) {
++ // RFC 1035 3.1 limits a name to 255 octets. A longer name (here built from
++ // six 63-octet labels) must be rejected instead of expanded.
++ std::vector<byte> data = {
++ 0x12, 0x34, 0x81, 0x80,
++ 0x00, 0x01, // num questions
++ 0x00, 0x01, // num answer RRs
++ 0x00, 0x00, // num authority RRs
++ 0x00, 0x00, // num additional RRs
++ // Question
++ 0x01, 'a', 0x00,
++ 0x00, 0x01, // type A
++ 0x00, 0x01, // class IN
++ };
++ // Answer name: 6 x 63 label octets + 5 separators = 383 presentation octets
++ // (> 255), then root terminator
++ for (int i = 0; i < 6; i++) {
++ data.push_back(63);
++ for (int j = 0; j < 63; j++) {
++ data.push_back('a');
++ }
++ }
++ data.push_back(0x00);
++ std::vector<byte> tail = {
++ 0x00, 0x01, // type A
++ 0x00, 0x01, // class IN
++ 0x00, 0x00, 0x00, 0x00, // TTL
++ 0x00, 0x04, // rdata length
++ 0x01, 0x02, 0x03, 0x04,
++ };
++ data.insert(data.end(), tail.begin(), tail.end());
++
++ ares_dns_record_t *dnsrec = NULL;
++ EXPECT_EQ(ARES_EBADNAME, ares_dns_parse(data.data(), data.size(), 0, &dnsrec));
++ EXPECT_EQ(nullptr, dnsrec);
++}
++
++TEST_F(LibraryTest, ParseRejectsOverlongNameViaPointers) {
++ // The answer name is one 63-octet label followed by a compression pointer back
++ // to the question name (four 63-octet labels). Expanded that is 5 x 63 label
++ // octets + 4 separators = 319 presentation octets (> 255), so the length has
++ // to accumulate across the pointer jump for this to be rejected.
++ std::vector<byte> data = {
++ 0x12, 0x34, 0x81, 0x80,
++ 0x00, 0x01, // num questions
++ 0x00, 0x01, // num answer RRs
++ 0x00, 0x00, // num authority RRs
++ 0x00, 0x00, // num additional RRs
++ };
++ // Question name: 4 x 63 label octets + 3 separators = 255 presentation octets,
++ // exactly the limit, so the question itself is accepted.
++ for (int i = 0; i < 4; i++) {
++ data.push_back(63);
++ for (int j = 0; j < 63; j++) {
++ data.push_back('a');
++ }
++ }
++ data.push_back(0x00);
++ std::vector<byte> qtail = {0x00, 0x01, 0x00, 0x01}; // type A, class IN
++ data.insert(data.end(), qtail.begin(), qtail.end());
++ // Answer name: one 63-octet label, then a pointer to the question name.
++ data.push_back(63);
++ for (int j = 0; j < 63; j++) {
++ data.push_back('a');
++ }
++ data.push_back(0xc0);
++ data.push_back(0x0c); // -> offset 12, start of question name
++ std::vector<byte> tail = {
++ 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 1, 2, 3, 4,
++ };
++ data.insert(data.end(), tail.begin(), tail.end());
++ ares_dns_record_t *dnsrec = NULL;
++ EXPECT_EQ(ARES_EBADNAME, ares_dns_parse(data.data(), data.size(), 0, &dnsrec));
++ EXPECT_EQ(nullptr, dnsrec);
++}
++
++TEST_F(LibraryTest, ParseRejectsPointerChain) {
++ // A name built purely from compression pointers adds no label octets, so the
++ // length cap alone can never stop it. A long backward chain of pointers is
++ // hidden in the opaque rdata of a raw RR, and a second RR's name points at the
++ // top of the chain; walking it must trip the indirection cap and return
++ // EBADNAME rather than following every jump.
++ std::vector<byte> data = {
++ 0x12, 0x34, 0x81, 0x80,
++ 0x00, 0x01, // num questions
++ 0x00, 0x02, // num answer RRs
++ 0x00, 0x00, // num authority RRs
++ 0x00, 0x00, // num additional RRs
++ // Question
++ 0x01, 'a', 0x00,
++ 0x00, 0x01, // type A
++ 0x00, 0x01, // class IN
++ // RR1: raw RR (unknown type) whose rdata carries the pointer chain
++ 0x00, // name = root
++ 0xff, 0xfe, // type (unknown -> stored raw, rdata not name-parsed)
++ 0x00, 0x01, // class IN
++ 0x00, 0x00, 0x00, 0x00, // TTL
++ };
++ // The chain lives in RR1's rdata, which begins two octets past here (after the
++ // rdlength we are about to write), so compute absolute offsets from there.
++ const size_t rdata_off = data.size() + 2;
++ std::vector<byte> chain;
++ chain.push_back(0x00); // deepest target: root terminator
++ size_t prev = rdata_off; // absolute offset of the root
++ size_t top = prev;
++ const int N = 200; // well past the 128 indirection cap
++ for (int i = 0; i < N; i++) {
++ size_t here = rdata_off + chain.size();
++ chain.push_back(0xc0 | ((prev >> 8) & 0x3f));
++ chain.push_back(prev & 0xff);
++ top = here;
++ prev = here;
++ }
++ data.push_back((chain.size() >> 8) & 0xff); // rdlength
++ data.push_back(chain.size() & 0xff);
++ data.insert(data.end(), chain.begin(), chain.end());
++ // RR2: name = pointer to the top of the chain.
++ data.push_back(0xc0 | ((top >> 8) & 0x3f));
++ data.push_back(top & 0xff);
++ std::vector<byte> tail = {
++ 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 1, 2, 3, 4,
++ };
++ data.insert(data.end(), tail.begin(), tail.end());
++
++ ares_dns_record_t *dnsrec = NULL;
++ EXPECT_EQ(ARES_EBADNAME, ares_dns_parse(data.data(), data.size(), 0, &dnsrec));
++ EXPECT_EQ(nullptr, dnsrec);
++}
++
++TEST_F(LibraryTest, ParseAcceptsMaxLengthName) {
++ // Exactly 255 presentation octets: 4 x 63 = 252 + 3 separators = 255, which
++ // must still be accepted (the bound is "> 255", not ">= 255").
++ std::vector<byte> data = {
++ 0x12, 0x34, 0x81, 0x80, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00,
++ 0x00, 0x00, 0x01, 'a', 0x00, 0x00, 0x01, 0x00, 0x01,
++ };
++ for (int i = 0; i < 4; i++) {
++ data.push_back(63);
++ for (int j = 0; j < 63; j++) {
++ data.push_back('a');
++ }
++ }
++ data.push_back(0x00);
++ std::vector<byte> tail = {
++ 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 1, 2, 3, 4,
++ };
++ data.insert(data.end(), tail.begin(), tail.end());
++ ares_dns_record_t *dnsrec = NULL;
++ EXPECT_EQ(ARES_SUCCESS, ares_dns_parse(data.data(), data.size(), 0, &dnsrec));
++ EXPECT_NE(nullptr, dnsrec);
++ ares_dns_record_destroy(dnsrec);
++}
++
++TEST_F(LibraryTest, ParseRejectsName256) {
++ // One octet over: labels 63,63,63,62,1 = 252 + 4 separators = 256 -> reject.
++ std::vector<byte> data = {
++ 0x12, 0x34, 0x81, 0x80, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00,
++ 0x00, 0x00, 0x01, 'a', 0x00, 0x00, 0x01, 0x00, 0x01,
++ };
++ const int lens[] = {63, 63, 63, 62, 1};
++ for (int i = 0; i < 5; i++) {
++ data.push_back(static_cast<byte>(lens[i]));
++ for (int j = 0; j < lens[i]; j++) {
++ data.push_back('a');
++ }
++ }
++ data.push_back(0x00);
++ std::vector<byte> tail = {
++ 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 1, 2, 3, 4,
++ };
++ data.insert(data.end(), tail.begin(), tail.end());
++ ares_dns_record_t *dnsrec = NULL;
++ EXPECT_EQ(ARES_EBADNAME, ares_dns_parse(data.data(), data.size(), 0, &dnsrec));
++ EXPECT_EQ(nullptr, dnsrec);
++}
++
+ } // namespace test
+ } // namespace ares
@@ -8,6 +8,7 @@ LIC_FILES_CHKSUM = "file://LICENSE.md;md5=fdbc58a6da11a9f68aa73c453818decc"
SRC_URI = "https://github.com/c-ares/c-ares/releases/download/cares-1_27_0/${BPN}-${PV}.tar.gz \
file://run-ptest \
file://CVE-2026-69186.patch \
+ file://CVE-2026-69184.patch \
"
SRC_URI[sha256sum] = "0a72be66959955c43e2af2fbd03418e82a2bd5464604ec9a62147e37aceb420b"