feat: harden proxy_dns hooks and improve ipv6 compatibility

README.md

@@ -250,6 +250,8 @@ proxychains4 --group jp curl https://ifconfig.me
 
 IPv6 notes:
 - IPv6 targets are supported through SOCKS5/HTTP proxy hops.
+- With `proxy_dns` enabled, hostname lookups avoid system-DNS fallback paths.
+- `getaddrinfo(AF_INET6)` is handled via IPv4-mapped fake addresses for compatibility.
 - SOCKS4/4a does not support IPv6 target addresses.
 
 Validation and discovery:

proxychains/src/hook/hooks.rs

@@ -50,7 +50,8 @@ impl HookState {
 /// Global hook state
 static HOOK_STATE: OnceLock<HookState> = OnceLock::new();
 /// Track addrinfo/sockaddr allocations created by our getaddrinfo hook.
-static CUSTOM_ADDRINFO_ALLOCATIONS: OnceLock<Mutex<HashMap<usize, usize>>> = OnceLock::new();
+static CUSTOM_ADDRINFO_ALLOCATIONS: OnceLock<Mutex<HashMap<usize, CustomAddrinfoAllocation>>> =
+    OnceLock::new();
 
 thread_local! {
     static GETHOSTBYNAME_STORE: RefCell<Option<Box<HostentStore>>> = const { RefCell::new(None) };
@@ -63,7 +64,13 @@ struct HostentStore {
     hostent: libc::hostent,
 }
 
-fn custom_alloc_map() -> &'static Mutex<HashMap<usize, usize>> {
+#[derive(Clone, Copy)]
+struct CustomAddrinfoAllocation {
+    sockaddr_ptr: usize,
+    family: libc::c_int,
+}
+
+fn custom_alloc_map() -> &'static Mutex<HashMap<usize, CustomAddrinfoAllocation>> {
     CUSTOM_ADDRINFO_ALLOCATIONS.get_or_init(|| Mutex::new(HashMap::new()))
 }
 
@@ -93,6 +100,106 @@ unsafe fn write_hostname_to_buf(host: *mut c_char, hostlen: libc::socklen_t, hos
     0
 }
 
+unsafe fn store_fake_addrinfo_result(
+    fake_ip: std::net::Ipv4Addr,
+    service_port: u16,
+    hints: *const libc::addrinfo,
+    requested_family: libc::c_int,
+    res: *mut *mut libc::addrinfo,
+) -> c_int {
+    match requested_family {
+        libc::AF_INET => {
+            let mut sockaddr: libc::sockaddr_in = std::mem::zeroed();
+            #[cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd"))]
+            {
+                sockaddr.sin_len = std::mem::size_of::<libc::sockaddr_in>() as u8;
+            }
+            sockaddr.sin_family = libc::AF_INET as libc::sa_family_t;
+            sockaddr.sin_port = service_port.to_be();
+            sockaddr.sin_addr = libc::in_addr {
+                s_addr: u32::from_ne_bytes(fake_ip.octets()),
+            };
+
+            let sockaddr_ptr = Box::into_raw(Box::new(sockaddr));
+            let mut ai: libc::addrinfo = std::mem::zeroed();
+            ai.ai_flags = if hints.is_null() { 0 } else { (*hints).ai_flags };
+            ai.ai_family = libc::AF_INET;
+            ai.ai_socktype = if hints.is_null() {
+                libc::SOCK_STREAM
+            } else {
+                (*hints).ai_socktype
+            };
+            ai.ai_protocol = if hints.is_null() {
+                libc::IPPROTO_TCP
+            } else {
+                (*hints).ai_protocol
+            };
+            ai.ai_addrlen = std::mem::size_of::<libc::sockaddr_in>() as libc::socklen_t;
+            ai.ai_addr = sockaddr_ptr as *mut libc::sockaddr;
+            ai.ai_canonname = std::ptr::null_mut();
+            ai.ai_next = std::ptr::null_mut();
+
+            let ai_ptr = Box::into_raw(Box::new(ai));
+            *res = ai_ptr;
+            custom_alloc_map().lock().insert(
+                ai_ptr as usize,
+                CustomAddrinfoAllocation {
+                    sockaddr_ptr: sockaddr_ptr as usize,
+                    family: libc::AF_INET,
+                },
+            );
+            0
+        }
+        libc::AF_INET6 => {
+            let mut mapped = [0u8; 16];
+            mapped[10] = 0xff;
+            mapped[11] = 0xff;
+            mapped[12..16].copy_from_slice(&fake_ip.octets());
+
+            let mut sockaddr: libc::sockaddr_in6 = std::mem::zeroed();
+            #[cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd"))]
+            {
+                sockaddr.sin6_len = std::mem::size_of::<libc::sockaddr_in6>() as u8;
+            }
+            sockaddr.sin6_family = libc::AF_INET6 as libc::sa_family_t;
+            sockaddr.sin6_port = service_port.to_be();
+            sockaddr.sin6_addr = libc::in6_addr { s6_addr: mapped };
+            sockaddr.sin6_scope_id = 0;
+
+            let sockaddr_ptr = Box::into_raw(Box::new(sockaddr));
+            let mut ai: libc::addrinfo = std::mem::zeroed();
+            ai.ai_flags = if hints.is_null() { 0 } else { (*hints).ai_flags };
+            ai.ai_family = libc::AF_INET6;
+            ai.ai_socktype = if hints.is_null() {
+                libc::SOCK_STREAM
+            } else {
+                (*hints).ai_socktype
+            };
+            ai.ai_protocol = if hints.is_null() {
+                libc::IPPROTO_TCP
+            } else {
+                (*hints).ai_protocol
+            };
+            ai.ai_addrlen = std::mem::size_of::<libc::sockaddr_in6>() as libc::socklen_t;
+            ai.ai_addr = sockaddr_ptr as *mut libc::sockaddr;
+            ai.ai_canonname = std::ptr::null_mut();
+            ai.ai_next = std::ptr::null_mut();
+
+            let ai_ptr = Box::into_raw(Box::new(ai));
+            *res = ai_ptr;
+            custom_alloc_map().lock().insert(
+                ai_ptr as usize,
+                CustomAddrinfoAllocation {
+                    sockaddr_ptr: sockaddr_ptr as usize,
+                    family: libc::AF_INET6,
+                },
+            );
+            0
+        }
+        _ => libc::EAI_FAMILY,
+    }
+}
+
 /// Initialize the hook library
 pub fn init_hooks(config: Config) -> Result<()> {
     // Initialize original functions first
@@ -161,12 +268,24 @@ pub unsafe fn hook_connect(
     }
 
     // Apply DNAT if configured
-    let (final_ip, final_port) = state.config.apply_dnat_ip(&target_ip, target_port);
+    let (dnat_ip, final_port) = state.config.apply_dnat_ip(&target_ip, target_port);
 
-    // Check if this is a fake IP (needs remote DNS resolution)
-    let target_domain = match final_ip {
-        IpAddr::V4(v4) if is_fake_ip(&v4) => state.dns_resolver.get_hostname(&v4),
-        _ => None,
+    // Check if this is a fake IP (needs remote DNS resolution). For IPv6-mapped
+    // fake addresses, collapse to IPv4 so SOCKS4a path can still use the domain.
+    let (final_ip, target_domain) = match dnat_ip {
+        IpAddr::V4(v4) if is_fake_ip(&v4) => (IpAddr::V4(v4), state.dns_resolver.get_hostname(&v4)),
+        IpAddr::V6(v6) => {
+            if let Some(v4) = v6.to_ipv4_mapped() {
+                if is_fake_ip(&v4) {
+                    (IpAddr::V4(v4), state.dns_resolver.get_hostname(&v4))
+                } else {
+                    (IpAddr::V6(v6), None)
+                }
+            } else {
+                (IpAddr::V6(v6), None)
+            }
+        }
+        _ => (dnat_ip, None),
     };
 
     // Check if proxy DNS is enabled and we have a domain
@@ -265,65 +384,36 @@ pub unsafe fn hook_getaddrinfo(
         return original_getaddrinfo(node, service, hints, res);
     }
 
-    // Preserve behavior for literal IPv4 strings.
-    if hostname.parse::<std::net::Ipv4Addr>().is_ok() {
+    // Preserve behavior for literal IP strings.
+    if hostname.parse::<std::net::IpAddr>().is_ok() {
         return original_getaddrinfo(node, service, hints, res);
     }
 
-    // Respect non-IPv4 family hints.
-    if !hints.is_null() {
-        let ai_family = (*hints).ai_family;
-        if ai_family != libc::AF_INET && ai_family != libc::AF_UNSPEC {
-            return original_getaddrinfo(node, service, hints, res);
+    let requested_family = if hints.is_null() {
+        libc::AF_INET
+    } else {
+        match (*hints).ai_family {
+            libc::AF_UNSPEC => libc::AF_INET,
+            libc::AF_INET => libc::AF_INET,
+            libc::AF_INET6 => libc::AF_INET6,
+            _ => return libc::EAI_FAMILY,
         }
-    }
+    };
 
     // Generate fake IP
     let fake_ip = match state.dns_resolver.resolve(&hostname) {
         Ok(ip) => ip,
         Err(e) => {
             error!("Failed to resolve {} in hook_getaddrinfo: {}", hostname, e);
-            return original_getaddrinfo(node, service, hints, res);
+            return libc::EAI_NONAME;
         }
     };
 
     let service_port = parse_service_port(service);
-
-    let mut sockaddr: libc::sockaddr_in = std::mem::zeroed();
-    #[cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd"))]
-    {
-        sockaddr.sin_len = std::mem::size_of::<libc::sockaddr_in>() as u8;
+    let ret = store_fake_addrinfo_result(fake_ip, service_port, hints, requested_family, res);
+    if ret != 0 {
+        return ret;
     }
-    sockaddr.sin_family = libc::AF_INET as libc::sa_family_t;
-    sockaddr.sin_port = service_port.to_be();
-    sockaddr.sin_addr = libc::in_addr {
-        s_addr: u32::from_ne_bytes(fake_ip.octets()),
-    };
-
-    let sockaddr_ptr = Box::into_raw(Box::new(sockaddr));
-    let mut ai: libc::addrinfo = std::mem::zeroed();
-    ai.ai_flags = if hints.is_null() { 0 } else { (*hints).ai_flags };
-    ai.ai_family = libc::AF_INET;
-    ai.ai_socktype = if hints.is_null() {
-        libc::SOCK_STREAM
-    } else {
-        (*hints).ai_socktype
-    };
-    ai.ai_protocol = if hints.is_null() {
-        libc::IPPROTO_TCP
-    } else {
-        (*hints).ai_protocol
-    };
-    ai.ai_addrlen = std::mem::size_of::<libc::sockaddr_in>() as libc::socklen_t;
-    ai.ai_addr = sockaddr_ptr as *mut libc::sockaddr;
-    ai.ai_canonname = std::ptr::null_mut();
-    ai.ai_next = std::ptr::null_mut();
-
-    let ai_ptr = Box::into_raw(Box::new(ai));
-    *res = ai_ptr;
-    custom_alloc_map()
-        .lock()
-        .insert(ai_ptr as usize, sockaddr_ptr as usize);
 
     debug!("Assigned fake IP {} for {}", fake_ip, hostname);
 
@@ -361,8 +451,8 @@ pub unsafe fn hook_gethostbyname(name: *const c_char) -> *mut libc::hostent {
         return original_gethostbyname(name);
     }
 
-    // Preserve behavior for literal IPv4 strings.
-    if hostname.parse::<std::net::Ipv4Addr>().is_ok() {
+    // Preserve behavior for literal IP strings.
+    if hostname.parse::<std::net::IpAddr>().is_ok() {
         return original_gethostbyname(name);
     }
 
@@ -371,7 +461,7 @@ pub unsafe fn hook_gethostbyname(name: *const c_char) -> *mut libc::hostent {
         Ok(ip) => ip,
         Err(e) => {
             error!("Failed to resolve {} in hook_gethostbyname: {}", hostname, e);
-            return original_gethostbyname(name);
+            return std::ptr::null_mut();
         }
     };
 
@@ -415,8 +505,12 @@ pub unsafe fn hook_freeaddrinfo(res: *mut libc::addrinfo) {
         return;
     }
 
-    if let Some(sockaddr_ptr) = custom_alloc_map().lock().remove(&(res as usize)) {
-        let _ = Box::from_raw(sockaddr_ptr as *mut libc::sockaddr_in);
+    if let Some(alloc) = custom_alloc_map().lock().remove(&(res as usize)) {
+        if alloc.family == libc::AF_INET6 {
+            let _ = Box::from_raw(alloc.sockaddr_ptr as *mut libc::sockaddr_in6);
+        } else {
+            let _ = Box::from_raw(alloc.sockaddr_ptr as *mut libc::sockaddr_in);
+        }
         let _ = Box::from_raw(res);
         return;
     }

proxychains/src/hook/hooks_windows.rs

@@ -4,7 +4,7 @@
 //! chain on the original socket handle.
 
 use std::collections::HashMap;
-use std::ffi::{c_void, CStr};
+use std::ffi::{c_void, CStr, CString};
 use std::mem::{self, ManuallyDrop};
 use std::net::{IpAddr, Ipv4Addr};
 use std::os::windows::io::FromRawSocket;
@@ -17,13 +17,14 @@ use tracing::{debug, error, info, warn};
 use windows::Win32::Networking::WinSock::{
     ADDRINFOA, AF_INET, IN_ADDR, IN_ADDR_0, IPPROTO_TCP, SOCKADDR, SOCKADDR_IN, SOCK_STREAM,
     SOCKET_ERROR, WSAEALREADY, WSAECONNREFUSED, WSAEFAULT, WSAEINPROGRESS, WSAEINVAL,
+    WSAHOST_NOT_FOUND,
     WSAEWOULDBLOCK, WSAGetLastError, WSASetLastError,
 };
 
 use crate::config::{ChainType, Config, ProxyData, ProxyState};
 use crate::dns::{is_fake_ip, DnsResolver};
 use crate::error::{Error, Result};
-use crate::net::{get_ip_from_sockaddr, get_port_from_sockaddr};
+use crate::net::{get_ip_from_sockaddr, get_ipaddr_from_sockaddr, get_port_from_sockaddr};
 use crate::proxy::{tunnel_through_proxy, TargetAddress};
 
 use super::interpose_windows::{
@@ -253,27 +254,37 @@ pub unsafe extern "system" fn hook_connect_impl(
         return original_connect(sock, addr, len);
     }
 
-    let target_ip = match get_ip_from_sockaddr(addr) {
+    let target_ip = match get_ipaddr_from_sockaddr(addr) {
         Some(ip) => ip,
         None => return original_connect(sock, addr, len),
     };
     let target_port = get_port_from_sockaddr(addr);
 
-    if state.config.should_bypass(&target_ip) {
+    if state.config.should_bypass_ip(&target_ip) {
         return original_connect(sock, addr, len);
     }
 
-    let (final_ip, final_port) = state.config.apply_dnat(&target_ip, target_port);
-    let target_domain = if is_fake_ip(&final_ip) {
-        state.dns_resolver.get_hostname(&final_ip)
-    } else {
-        None
+    let (dnat_ip, final_port) = state.config.apply_dnat_ip(&target_ip, target_port);
+    let (final_ip, target_domain) = match dnat_ip {
+        IpAddr::V4(v4) if is_fake_ip(&v4) => (IpAddr::V4(v4), state.dns_resolver.get_hostname(&v4)),
+        IpAddr::V6(v6) => {
+            if let Some(v4) = v6.to_ipv4_mapped() {
+                if is_fake_ip(&v4) {
+                    (IpAddr::V4(v4), state.dns_resolver.get_hostname(&v4))
+                } else {
+                    (IpAddr::V6(v6), None)
+                }
+            } else {
+                (IpAddr::V6(v6), None)
+            }
+        }
+        _ => (dnat_ip, None),
     };
 
     let target = if let Some(domain) = target_domain {
-        TargetAddress::from_both(IpAddr::V4(final_ip), domain)
+        TargetAddress::from_both(final_ip, domain)
     } else {
-        TargetAddress::from_ip(IpAddr::V4(final_ip))
+        TargetAddress::from_ip(final_ip)
     };
 
     let max_attempts = state.config.max_chain_retries.max(1);
@@ -340,7 +351,7 @@ pub unsafe extern "system" fn hook_getaddrinfo_impl(
     if !phints.is_null() {
         let hints = &*(phints as *const ADDRINFOA);
         if hints.ai_family != 0 && hints.ai_family != AF_INET.0 as i32 {
-            return original_getaddrinfo(pnode, pservice, phints, ppresult);
+            return WSAHOST_NOT_FOUND.0;
         }
     }
 
@@ -349,7 +360,7 @@ pub unsafe extern "system" fn hook_getaddrinfo_impl(
         Err(_) => return original_getaddrinfo(pnode, pservice, phints, ppresult),
     };
 
-    if hostname.parse::<Ipv4Addr>().is_ok() {
+    if hostname.parse::<IpAddr>().is_ok() {
         return original_getaddrinfo(pnode, pservice, phints, ppresult);
     }
 
@@ -361,7 +372,7 @@ pub unsafe extern "system" fn hook_getaddrinfo_impl(
         Ok(ip) => ip,
         Err(e) => {
             error!("Failed to resolve {} in hook_getaddrinfo_impl: {}", hostname, e);
-            return original_getaddrinfo(pnode, pservice, phints, ppresult);
+            return WSAHOST_NOT_FOUND.0;
         }
     };
 
@@ -414,7 +425,54 @@ pub unsafe extern "system" fn hook_freeaddrinfo_impl(pres: *mut c_void) {
 /// Windows gethostbyname hook implementation.
 #[cfg(windows)]
 pub unsafe extern "system" fn hook_gethostbyname_impl(name: *const i8) -> *mut c_void {
-    original_gethostbyname(name)
+    let state = match get_hook_state() {
+        Some(s) if s.config.proxy_dns => s,
+        _ => return original_gethostbyname(name),
+    };
+
+    if name.is_null() {
+        WSASetLastError(WSAEINVAL.0);
+        return std::ptr::null_mut();
+    }
+
+    let hostname = match CStr::from_ptr(name).to_str() {
+        Ok(s) => s,
+        Err(_) => {
+            WSASetLastError(WSAEINVAL.0);
+            return std::ptr::null_mut();
+        }
+    };
+
+    if hostname.parse::<IpAddr>().is_ok() {
+        return original_gethostbyname(name);
+    }
+
+    if crate::dns::lookup_in_hosts(hostname).is_some() {
+        return original_gethostbyname(name);
+    }
+
+    let fake_ip = match state.dns_resolver.resolve(hostname) {
+        Ok(ip) => ip,
+        Err(e) => {
+            error!("Failed to resolve {} in hook_gethostbyname_impl: {}", hostname, e);
+            WSASetLastError(WSAHOST_NOT_FOUND.0);
+            return std::ptr::null_mut();
+        }
+    };
+
+    let fake_ip_cstr = match CString::new(fake_ip.to_string()) {
+        Ok(v) => v,
+        Err(_) => {
+            WSASetLastError(WSAHOST_NOT_FOUND.0);
+            return std::ptr::null_mut();
+        }
+    };
+
+    let result = original_gethostbyname(fake_ip_cstr.as_ptr());
+    if result.is_null() {
+        WSASetLastError(WSAHOST_NOT_FOUND.0);
+    }
+    result
 }
 
 /// Windows getnameinfo hook implementation.

proxychains/src/net/socket_windows.rs

@@ -3,7 +3,7 @@
 //! This module provides Windows-specific implementations for socket operations
 //! using the Winsock2 API.
 
-use std::net::Ipv4Addr;
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 
 /// Get the port from a SOCKADDR structure (Windows-specific)
 #[cfg(windows)]
@@ -18,6 +18,10 @@ pub fn get_port_from_sockaddr(addr: *const core::ffi::c_void) -> u16 {
             // sin_port: u16 (2 bytes) - network byte order
             let port_ptr = (addr as *const u8).add(2) as *const u16;
             u16::from_be(*port_ptr)
+        } else if sa_family == 23 {
+            // SOCKADDR_IN6 has the same port offset.
+            let port_ptr = (addr as *const u8).add(2) as *const u16;
+            u16::from_be(*port_ptr)
         } else {
             0
         }
@@ -49,6 +53,28 @@ pub fn get_ip_from_sockaddr(addr: *const core::ffi::c_void) -> Option<Ipv4Addr>
     }
 }
 
+/// Get the IP address (IPv4/IPv6) from a SOCKADDR structure.
+#[cfg(windows)]
+pub fn get_ipaddr_from_sockaddr(addr: *const core::ffi::c_void) -> Option<IpAddr> {
+    unsafe {
+        let sa_family = *(addr as *const u16);
+        if sa_family == 2 {
+            let ip_ptr = (addr as *const u8).add(4);
+            let ip_bytes = [*ip_ptr, *ip_ptr.add(1), *ip_ptr.add(2), *ip_ptr.add(3)];
+            Some(IpAddr::V4(Ipv4Addr::from(ip_bytes)))
+        } else if sa_family == 23 {
+            // SOCKADDR_IN6 layout:
+            // sin6_family (2), sin6_port (2), sin6_flowinfo (4), sin6_addr (16), sin6_scope_id (4)
+            let ip_ptr = (addr as *const u8).add(8);
+            let mut octets = [0u8; 16];
+            std::ptr::copy_nonoverlapping(ip_ptr, octets.as_mut_ptr(), 16);
+            Some(IpAddr::V6(Ipv6Addr::from(octets)))
+        } else {
+            None
+        }
+    }
+}
+
 /// Create a TCP socket (Windows-specific)
 pub fn create_tcp_socket() -> std::io::Result<std::net::TcpStream> {
     use socket2::{Domain, Protocol, Socket, Type};
@@ -126,4 +152,26 @@ mod tests {
         assert!(is_localhost(&Ipv4Addr::new(127, 0, 0, 1)));
         assert!(!is_localhost(&Ipv4Addr::new(192, 168, 1, 1)));
     }
+
+    #[test]
+    fn test_parse_ipv6_sockaddr_layout() {
+        // Build a minimal SOCKADDR_IN6 byte layout.
+        let mut raw = [0u8; 28];
+        raw[0] = 23; // AF_INET6 low byte
+        raw[1] = 0;
+        raw[2] = 0x13; // port 4919 in network byte order
+        raw[3] = 0x37;
+        raw[8..24].copy_from_slice(&[
+            0x20, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
+        ]);
+
+        let addr_ptr = raw.as_ptr() as *const core::ffi::c_void;
+        assert_eq!(get_port_from_sockaddr(addr_ptr), 4919);
+        assert_eq!(
+            get_ipaddr_from_sockaddr(addr_ptr),
+            Some(IpAddr::V6(Ipv6Addr::new(
+                0x2001, 0x0db8, 0, 0, 0, 0, 0, 1
+            )))
+        );
+    }
 }