Commit 075323d895 for strongswan.org

commit 075323d895f574424cfc4a5f491a1d388cdfda37
Author: R. Elliott Childre <elliottchildre329@gmail.com>
Date:   Mon May 18 00:53:24 2026 -0400

    identification: Fix double-free when cloning empty IDs

    The clone() method was missing a branch when there is an encoded chunk
    of length 0 that still needed to be cloned.  Otherwise, the destruction
    of the clone frees the same pointer that the original owns.

    This double free was found with an improved `fuzz_ids` fuzz harness and
    a two byte input to create an identification from "@#" or [0x40, 0x23].
    It can also be triggered with `<type>:#` e.g. `dns:#`.

    One of the problematic constructors is used to parse EAP-Identities,
    which are cloned before storing them in the auth-cfg.   So this can be
    triggered by an unauthenticated attacker.

    Note that while the length check was already added with 418dbd624363
    ("cloning %any ID without zero-byte memleak") and identities that trigger
    this can be created since 86ab5636c2c9 ("support for @#hex ID_KEY_ID
    identification_t"), it was the referenced commit that made the length
    check problematic.

    Fixes: 2147da40a5d7 ("simplified identification_t.clone() using memcpy")
    Fixes: CVE-2026-47895

diff --git a/fuzz/fuzz_ids.c b/fuzz/fuzz_ids.c
index aff9162544..5c6b344a58 100644
--- a/fuzz/fuzz_ids.c
+++ b/fuzz/fuzz_ids.c
@@ -19,14 +19,37 @@

 int LLVMFuzzerTestOneInput(const uint8_t *buf, size_t len)
 {
-	identification_t *id;
-	chunk_t chunk;
+	identification_t *id, *clone;
+	enumerator_t *part_enum;
+	chunk_t chunk, data;
+	id_part_t part;
+	char str_buf[BUF_LEN], min_buf[3];

 	dbg_default_set_level(-1);
 	library_init(NULL, "fuzz_ids");

 	chunk = chunk_create((u_char*)buf, len);
 	id = identification_create_from_data(chunk);
+	if (id)
+	{
+		id->hash(id, 0U);
+		id->equals(id, id);
+		id->matches(id, id);
+		id->contains_wildcards(id);
+
+		part_enum = id->create_part_enumerator(id);
+		if (part_enum)
+		{
+			while (part_enum->enumerate(part_enum, &part, &data));
+			part_enum->destroy(part_enum);
+		}
+
+		clone = id->clone(id);
+		clone->destroy(clone);
+	}
+
+	snprintf(str_buf, sizeof(str_buf), "%Y", id);
+	snprintf(min_buf, sizeof(min_buf), "%Y", id);
 	DESTROY_IF(id);

 	library_deinit();
diff --git a/src/libstrongswan/tests/suites/test_identification.c b/src/libstrongswan/tests/suites/test_identification.c
index e7a4d4493e..b318fc659b 100644
--- a/src/libstrongswan/tests/suites/test_identification.c
+++ b/src/libstrongswan/tests/suites/test_identification.c
@@ -1608,6 +1608,29 @@ START_TEST(test_clone)
 }
 END_TEST

+START_TEST(test_clone_empty)
+{
+	identification_t *a, *b;
+	chunk_t a_enc, b_enc;
+
+	/* this produces an empty but non-NULL encoding, which previously caused a
+	 * double-free when destroying a clone */
+	a = identification_create_from_string("@#");
+	ck_assert(a != NULL);
+	a_enc = a->get_encoding(a);
+
+	b = a->clone(a);
+	ck_assert(b != NULL);
+	ck_assert(a != b);
+	b_enc = b->get_encoding(b);
+	ck_assert(!a_enc.len && !b_enc.len);
+	ck_assert(a_enc.ptr != b_enc.ptr || (!a_enc.ptr && !b_enc.ptr));
+
+	b->destroy(b);
+	a->destroy(a);
+}
+END_TEST
+
 Suite *identification_suite_create()
 {
 	Suite *s;
@@ -1670,6 +1693,7 @@ Suite *identification_suite_create()

 	tc = tcase_create("clone");
 	tcase_add_test(tc, test_clone);
+	tcase_add_test(tc, test_clone_empty);
 	suite_add_tcase(s, tc);

 	return s;
diff --git a/src/libstrongswan/utils/identification.c b/src/libstrongswan/utils/identification.c
index 322c2c95ed..35837237c6 100644
--- a/src/libstrongswan/utils/identification.c
+++ b/src/libstrongswan/utils/identification.c
@@ -1722,7 +1722,7 @@ METHOD(identification_t, clone_, identification_t*,
 		clone->encoded = chunk_from_str(strdup(this->encoded.ptr));
 		compile_regex(clone);
 	}
-	else if (this->encoded.len)
+	else
 	{
 		clone->encoded = chunk_clone(this->encoded);
 	}