From 7a69ca5bc94d1705a4ce0cddcf3fed212e68b51e Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Sat, 4 Apr 2026 22:35:40 +0200
Subject: [PATCH] Refactor IPv6 zone ID parsing and reject malformed zone
 identifiers

---
 src/libsodium/sodium/codecs.c | 25 +++++++++++++++----------
 test/default/codecs.c         |  4 ++++
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/src/libsodium/sodium/codecs.c b/src/libsodium/sodium/codecs.c
index 33f081b1..39418bab 100644
--- a/src/libsodium/sodium/codecs.c
+++ b/src/libsodium/sodium/codecs.c
@@ -485,29 +485,34 @@ sodium_ip2bin(unsigned char bin[16], const char *ip,
               size_t ip_len_) /* Some AIX versions define a macro named "ip_len" */
 {
     const char   *ip_end = ip + ip_len_;
-    const char   *end;
+    const char   *end    = ip;
+    const char   *zone   = NULL;
     const char   *z;
     unsigned char v4[4];
+    int           is_ipv6;
 
-    for (end = ip; end < ip_end && *end != 0 && *end != '%'; end++) {
+    for (; end < ip_end && *end != 0; end++) {
         /* empty */
     }
-    if (end < ip_end && *end == '%') {
-        for (z = end + 1; z < ip_end && *z != 0; z++) {
-            if (isspace((unsigned char) *z)) {
+    zone = memchr(ip, '%', (size_t) (end - ip));
+    if (zone != NULL) {
+        for (z = zone + 1; z < end; z++) {
+            if (*z == '%' || isspace((unsigned char) *z)) {
                 return -1;
             }
         }
-        if (z == end + 1) {
+        if (zone + 1 >= end) {
             return -1;
         }
+        end = zone;
     }
-    if (memchr(ip, ':', (size_t) (end - ip)) != NULL) {
-        return parse_ipv6(ip, end, bin) != 0 ? 0 : -1;
-    }
-    if (end < ip_end && *end == '%') {
+    is_ipv6 = memchr(ip, ':', (size_t) (end - ip)) != NULL;
+    if (zone != NULL && !is_ipv6) {
         return -1;
     }
+    if (is_ipv6) {
+        return parse_ipv6(ip, end, bin) != 0 ? 0 : -1;
+    }
     if (parse_ipv4(ip, end, v4) == 0) {
         return -1;
     }
diff --git a/test/default/codecs.c b/test/default/codecs.c
index 6119e28f..2814ee23 100644
--- a/test/default/codecs.c
+++ b/test/default/codecs.c
@@ -307,6 +307,10 @@ main(void)
 
         assert(sodium_ip2bin(ip_bytes, "fe80::1%eth0", strlen("fe80::1%eth0")) == 0);
         assert(sodium_ip2bin(ip_bytes, "fe80::1%15", strlen("fe80::1%15")) == 0);
+        assert(sodium_ip2bin(ip_bytes, "fe80::1%%eth0", strlen("fe80::1%%eth0")) == -1);
+        assert(sodium_ip2bin(ip_bytes, "fe80::1%eth0%1", strlen("fe80::1%eth0%1")) == -1);
+        assert(sodium_ip2bin(ip_bytes, "fe80::1%eth 0", strlen("fe80::1%eth 0")) == -1);
+        assert(sodium_ip2bin(ip_bytes, "192.168.1.1%eth0", strlen("192.168.1.1%eth0")) == -1);
         printf("ip2bytes IPv6 zone: OK\n");
 
         assert(sodium_ip2bin(ip_bytes, "2001:::1", strlen("2001:::1")) == -1);