Update README.md (#431)

Updated tproxy.md location

.github/workflows/container-build.yaml

@@ -0,0 +1,63 @@
+name: Create and publish Container image
+
+on:
+  push:
+    branches:
+      - master
+    tags:
+      - 'v*'
+  pull_request:
+    branches:
+      - master
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Login to Container registry
+        uses: docker/login-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=edge
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+
+      - name: Build and push
+        uses: docker/build-push-action@v4
+        with:
+          platforms: linux/amd64,linux/386,linux/arm64,linux/arm/v6,linux/arm/v7
+          context: .
+          file: Dockerfile
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

.gitignore

@@ -3,8 +3,10 @@
 *.o
 cscope.*
 echosrv
+libsslh.a
 sslh-fork
 sslh-select
+sslh-ev
 sslh.8.gz
 tags
 version.h

ChangeLog

@@ -1,5 +1,21 @@
+v2.1.0:
+	Support for the Landlock LSM. After initial setup,
+	sslh gives up all local file access rights.
+
+	Reintroduced --ssl as an alias to --tls.
+
+	Introduce autoconf to adapt to landlock presence.
+
+	Close connexion without error message if remote
+	client forcefully closes connexion, for Windows.
+
+v2.0.1:	
+	Fix resolve_on_forward setting, which would crash
+	sslh reliably.
+
+v2.0.0:
 v2.0:
-	New sslh-ev: this is functionaly equivalent to
+	New sslh-ev: this is functionally equivalent to
 	sslh-select (mono-process, only forks for specified
 	protocols), but based on libev, which should make it
 	scalable to large numbers of connections.
@@ -41,7 +57,7 @@ v1.22: 17AUG2021
 	combined with incoming TLS with SNI.  UDP clients
 	and servers need to agree on the IPv4/IPv6 they use:
 	use the same protocol on all sides! Often, this
-	means explicitely using 'ip4-localhost'.
+	means explicitly using 'ip4-localhost'.
 	UDP sender-receiver pairs (connections, so to speak)
 	are kept for 60s, which can be changed with
 	`udp_timeout` in the configuration.
@@ -83,7 +99,7 @@ v1.21: 11JUL2020
 
 	Added TCP_FASTOPEN support for client sockets (if
 	tfo_ok is specified in their configuration) and for
-	listenint socket, if all client protocols support it.
+	listening socket, if all client protocols support it.
 	(Craig Andrews)
 
 	Added 'minlength' option to skip a probe if less
@@ -109,8 +125,8 @@ v1.20: 20NOV2018
 	Before, probes were tried in order, repeating on the
 	same probe as long it returned PROBE_AGAIN before
 	moving to the next one. This means a probe which
-	requires a lot of data (i.e. returne PROBE_AGAIN for
-	a long time) could prevent sucessful matches from 
+	requires a lot of data (i.e. return PROBE_AGAIN for
+	a long time) could prevent successful matches from 
 	subsequent probes. The configuration file needed to
 	take that into account.
 
@@ -171,7 +187,7 @@ v1.18:	29MAR2016
 v1.17: 	09MAR2015
 	Support RFC5952-style IPv6 addresses, e.g. [::]:443.
 
-	Transparant proxy support for FreeBSD.
+	Transparent proxy support for FreeBSD.
 	(Ruben van Staveren)
 
 	Using -F with no argument will try
@@ -200,7 +216,7 @@ v1.16:	11FEB2014
 
 	Libcap support: Keep only CAP_NET_ADMIN if started
 	as root with transparent proxying and dropping
-	priviledges (enable USELIBCAP in Makefile). This
+	privileges (enable USELIBCAP in Makefile). This
 	avoids having to mess with filesystem capabilities.
 	(Sebastian Schmidt/yath)
 
@@ -209,7 +225,7 @@ v1.16:	11FEB2014
 	actual errors if connections are dropped before
 	getting to getpeername).
 
-	Set IP_FREEDBIND if available to bind to addresses
+	Set IP_FREEBIND if available to bind to addresses
 	that don't yet exist.
 
 v1.15:	27JUL2013
@@ -294,7 +310,7 @@ v1.11: 21APR2012
 	--user isn't specified, just run as current user.
 
 	No longer create PID file by default, it should be
-	explicitely set with --pidfile.
+	explicitly set with --pidfile.
 
 	No longer log to syslog if in foreground. Logs are
 	instead output to stderr.
@@ -385,7 +401,7 @@ v1.8: 15JUL2011
 v1.7: 01FEB2010
 	Added CentOS init.d script (Andre Krajnik).
 
-	Fixed default ssl address inconsistancy, now
+	Fixed default ssl address inconsistency, now
 	defaults to "localhost:443" and fixed documentation
 	accordingly (pointed by Markus Schalke).
 

Dockerfile

@@ -1,23 +1,38 @@
-FROM alpine:latest as build
+ARG ALPINE_VERSION="latest"
+ARG TARGET_ARCH="library"
 
-ADD . /sslh
+FROM docker.io/${TARGET_ARCH}/alpine:${ALPINE_VERSION} AS build
 
-RUN \
-  apk add \
-    gcc \
-    libconfig-dev \
-    make \
-    musl-dev \
-    pcre2-dev \
-    perl && \
-  cd /sslh && \
-  make sslh-select && \
-  strip sslh-select
+WORKDIR /sslh
 
-FROM alpine:latest
+RUN apk add --no-cache \
+        'gcc' \
+        'libconfig-dev' \
+        'make' \
+        'musl-dev' \
+        'pcre2-dev' \
+        'perl' \
+        ;
 
-COPY --from=build /sslh/sslh-select /sslh
+COPY . /sslh
 
-RUN apk --no-cache add libconfig pcre2
+RUN ./configure && make sslh-select && strip sslh-select
 
-ENTRYPOINT [ "/sslh", "--foreground"]
+FROM docker.io/${TARGET_ARCH}/alpine:${ALPINE_VERSION}
+
+COPY --from=build "/sslh/sslh-select" "/usr/local/bin/sslh"
+RUN apk add --no-cache \
+        'libconfig' \
+        'pcre2' \
+        'iptables' \
+        'ip6tables' \
+        'libcap' \
+    && \
+    adduser -s '/bin/sh' -S -D sslh && \
+    setcap cap_net_bind_service,cap_net_raw+ep /usr/local/bin/sslh
+
+COPY "./container-entrypoint.sh" "/init"
+ENTRYPOINT [ "/init" ]
+
+# required for updating iptables
+USER root:root

Makefile.in

@@ -3,9 +3,11 @@ VERSION=$(shell ./genver.sh -r)
 
 # Configuration -- you probably need to `make clean` if you
 # change any of these
+# landlock is checked by `configure` and set in config.h
 ENABLE_SANITIZER= # Enable ASAN/LSAN/UBSAN
 ENABLE_REGEX=1  # Enable regex probes
 USELIBCONFIG=1	# Use libconfig? (necessary to use configuration files)
+USELIBEV=1	# Use libev?
 USELIBWRAP?=	# Use libwrap?
 USELIBCAP=	# Use libcap?
 USESYSTEMD=     # Make use of systemd socket activation
@@ -30,10 +32,11 @@ endif
 
 CC ?= gcc
 AR ?= ar
-CFLAGS ?=-Wall -O2 -DLIBPCRE -g $(CFLAGS_COV) $(CFLAGS_SAN)
+CFLAGS +=-Wall -O2 -DLIBPCRE -g $(CFLAGS_COV) $(CFLAGS_SAN)
+
 
 LIBS=-lm -lpcre2-8
-OBJS=sslh-conf.o common.o log.o sslh-main.o probe.o tls.o argtable3.o collection.o gap.o tcp-probe.o
+OBJS=sslh-conf.o common.o log.o sslh-main.o probe.o tls.o argtable3.o collection.o gap.o tcp-probe.o landlock.o
 OBJS_A=libsslh.a
 FORK_OBJS=sslh-fork.o $(OBJS_A)
 SELECT_OBJS=processes.o udp-listener.o sslh-select.o hash.o tcp-listener.o $(OBJS_A)
@@ -71,8 +74,11 @@ ifneq ($(strip $(USELIBBSD)),)
         CPPFLAGS+=-DLIBBSD
 endif
 
+ifneq ($(strip $(USELIBEV)),)
+        CONDITIONAL_TARGETS+=sslh-ev
+endif
 
-all: sslh $(MAN) echosrv $(CONDITIONAL_TARGETS)
+all: sslh-fork sslh-select $(MAN) echosrv $(CONDITIONAL_TARGETS)
 
 %.o: %.c %.h version.h
 	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
@@ -83,13 +89,15 @@ $(OBJS_A): $(OBJS)
 version.h:
 	./genver.sh >version.h
 
-sslh: sslh-fork sslh-select sslh-ev
-
 $(OBJS) $(FORK_OBJS) $(SELECT_OBJS) $(EV_OBJS): argtable3.h collection.h common.h gap.h hash.h log.h probe.h processes.h sslh-conf.h tcp-listener.h tcp-probe.h tls.h udp-listener.h version.h
 
 
-sslh-conf.c sslh-conf.h: sslhconf.cfg
+c2s:
 	conf2struct sslhconf.cfg
+	conf2struct echosrv.cfg
+
+sslh-conf.c sslh-conf.h: sslhconf.cfg
+	$(warning "sslhconf.cfg is more recent than sslh-conf.[ch]. Use `make c2s` to rebuild using `conf2struct`")
 
 sslh-fork: version.h Makefile $(FORK_OBJS)
 	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-fork $(FORK_OBJS) $(LIBS)
@@ -104,11 +112,14 @@ systemd-sslh-generator: systemd-sslh-generator.o
 	$(CC) $(CFLAGS) $(LDFLAGS) -o systemd-sslh-generator systemd-sslh-generator.o -lconfig
 
 echosrv-conf.c echosrv-conf.h: echosrv.cfg
-	conf2struct echosrv.cfg
+	$(warning "echosrv.cfg is more recent than echosrv-conf.[ch]. Use `make c2s` to rebuild using `conf2struct`")
 
 echosrv: version.h echosrv-conf.c echosrv.o echosrv-conf.o argtable3.o
 	$(CC) $(CFLAGS) $(LDFLAGS) -o echosrv echosrv.o echosrv-conf.o argtable3.o $(LIBS)
 
+
+landlock.o: config.h
+
 $(MAN): sslh.pod Makefile
 	pod2man --section=8 --release=$(VERSION) --center=" " sslh.pod | gzip -9 - > $(MAN)
 
@@ -128,7 +139,7 @@ docker-clean:
 	yes | docker image prune
 
 # generic install: install binary and man page
-install: sslh $(MAN)
+install: sslh-fork $(MAN)
 	mkdir -p $(DESTDIR)/$(BINDIR)
 	mkdir -p $(DESTDIR)/$(MANDIR)
 	install -p sslh-fork $(DESTDIR)/$(BINDIR)/sslh
@@ -148,7 +159,7 @@ distclean: clean
 	rm -f tags sslh-conf.[ch] echosrv-conf.[ch] cscope.*
 
 clean:
-	rm -f sslh-fork sslh-select sslh-ev echosrv version.h $(MAN) systemd-sslh-generator *.o *.gcov *.gcno *.gcda *.png *.html *.css *.info
+	rm -f sslh-fork sslh-select $(CONDITIONAL_TARGETS) echosrv version.h $(MAN) systemd-sslh-generator *.o *.gcov *.gcno *.gcda *.png *.html *.css *.info
 
 tags:
 	ctags --globals -T *.[ch]

README.md

@@ -11,7 +11,7 @@ protocol that can be tested using a regular expression, can
 be recognised. A typical use case is to allow serving
 several services on port 443 (e.g. to connect to SSH from
 inside a corporate firewall, which almost never block port
-443) while still serving HTTPS on that port. 
+443) while still serving HTTPS on that port.
 
 Hence `sslh` acts as a protocol demultiplexer, or a
 switchboard. With the SNI and ALPN probe, it makes a good
@@ -20,9 +20,10 @@ address.
 
 `sslh` has the bells and whistles expected from a mature
 daemon: privilege and capabilities dropping, inetd support,
-systemd support, transparent proxying, chroot, logging, 
-IPv4 and IPv6, TCP and UDP, a fork-based and a select-based 
-model, and more.
+systemd support, transparent proxying, chroot, logging,
+IPv4 and IPv6, TCP and UDP, a fork-based, a select-based
+model, and yet another based on libev for larger
+installations.
 
 Install
 =======
@@ -35,6 +36,18 @@ Configuration
 
 Please refer to the [configuration guide](doc/config.md).
 
+Transparent proxying allows the target server to see the
+original client IP address, i.e. `sslh` becomes invisible.
+This makes it easier to use the server's logs, and potential
+IP-based banning ability.
+
+Configuration of transparent proxying is highly dependent on
+your network environment and infrastructure setup. There is
+no known generic approach, and if you do not find directions
+for your exact setup, you will probably need an extensive
+knowledge of network management and iptables setup".
+
+It is described in its own [document](doc/tproxy.md).
 
 
 Docker image
@@ -44,16 +57,15 @@ How to use
 
 ---
 
-Build docker image
-
-    make docker
-
 
 ```bash
 docker run \
+  --cap-add CAP_NET_RAW \
+  --cap-add CAP_NET_BIND_SERVICE \
   --rm \
   -it \
-  sslh:latest \
+  ghcr.io/yrutschle/sslh:latest \
+  --foreground \
   --listen=0.0.0.0:443 \
   --ssh=hostname:22 \
   --tls=hostname:443
@@ -61,16 +73,16 @@ docker run \
 
 docker-compose example
 
-```
+```yaml
 version: "3"
 
 services:
   sslh:
-    image: sslh:latest
+    image: ghcr.io/yrutschle/sslh:latest
     hostname: sslh
     ports:
       - 443:443
-    command: --listen=0.0.0.0:443 --tls=nginx:443 --openvpn=openvpn:1194
+    command: --foreground --listen=0.0.0.0:443 --tls=nginx:443 --openvpn=openvpn:1194
     depends_on:
       - nginx
       - openvpn
@@ -82,6 +94,85 @@ services:
     image: openvpn
 ```
 
+Transparent mode 1: using sslh container for networking
+
+_Note: For transparent mode to work, the sslh container must be able to reach your services via **localhost**_
+```yaml
+version: "3"
+
+services:
+  sslh:
+    build: https://github.com/yrutschle/sslh.git
+    container_name: sslh
+    environment:
+      - TZ=${TZ}
+    cap_add:
+      - NET_ADMIN
+      - NET_RAW
+      - NET_BIND_SERVICE
+    sysctls:
+      - net.ipv4.conf.default.route_localnet=1
+      - net.ipv4.conf.all.route_localnet=1
+    command: --transparent --foreground --listen=0.0.0.0:443 --tls=localhost:8443 --openvpn=localhost:1194
+    ports:
+      - 443:443 #sslh
+
+      - 80:80 #nginx
+      - 8443:8443 #nginx
+
+      - 1194:1194 #openvpn
+    extra_hosts:
+      - localbox:host-gateway
+    restart: unless-stopped
+
+  nginx:
+    image: nginx:latest
+    .....
+    network_mode: service:sslh #set nginx container to use sslh networking.
+    # ^^^ This is required. This makes nginx reachable by sslh via localhost
+  
+  openvpn:
+    image: openvpn:latest
+    .....
+    network_mode: service:sslh #set openvpn container to use sslh networking
+```
+
+Transparent mode 2: using host networking
+
+```yaml
+version: "3"
+
+services:
+  sslh:
+    build: https://github.com/yrutschle/sslh.git
+    container_name: sslh
+    environment:
+      - TZ=${TZ}
+    cap_add:
+      - NET_ADMIN
+      - NET_RAW
+      - NET_BIND_SERVICE
+    # must be set manually
+    #sysctls:
+    #  - net.ipv4.conf.default.route_localnet=1
+    #  - net.ipv4.conf.all.route_localnet=1
+    command: --transparent --foreground --listen=0.0.0.0:443 --tls=localhost:8443 --openvpn=localhost:1194
+    network_mode: host
+    restart: unless-stopped
+  
+  nginx:
+    image: nginx:latest
+    .....
+    ports:
+      - 8443:8443 # bind to docker host on port 8443
+
+  openvpn:
+    image: openvpn:latest
+    .....
+    ports:
+      - 1194:1194 # bind to docker host on port 1194
+```
+
 Comments? Questions?
 ====================
 

argtable3.c

@@ -2876,9 +2876,9 @@ static void arg_file_resetfn(struct arg_file* parent) {
 static const char* arg_basename(const char* filename) {
     const char *result = NULL, *result1, *result2;
 
-    /* Find the last occurrence of eother file separator character. */
-    /* Two alternative file separator chars are supported as legal  */
-    /* file separators but not both together in the same filename.  */
+    /* Find the last occurrence of other file separator character. */
+    /* Two alternative file separator chars are supported as legal */
+    /* file separators but not both together in the same filename. */
     result1 = (filename ? strrchr(filename, FILESEPARATOR1) : NULL);
     result2 = (filename ? strrchr(filename, FILESEPARATOR2) : NULL);
 
@@ -2927,7 +2927,7 @@ static int arg_file_scanfn(struct arg_file* parent, const char* argval) {
     } else if (!argval) {
         /* a valid argument with no argument value was given. */
         /* This happens when an optional argument value was invoked. */
-        /* leave parent arguiment value unaltered but still count the argument. */
+        /* leave parent argument value unaltered but still count the argument. */
         parent->count++;
     } else {
         parent->filename[parent->count] = argval;
@@ -3173,7 +3173,7 @@ static int arg_int_scanfn(struct arg_int* parent, const char* argval) {
     } else if (!argval) {
         /* a valid argument with no argument value was given. */
         /* This happens when an optional argument value was invoked. */
-        /* leave parent arguiment value unaltered but still count the argument. */
+        /* leave parent argument value unaltered but still count the argument. */
         parent->count++;
     } else {
         long int val;
@@ -3813,8 +3813,8 @@ static const TRexChar* g_nnames[] = {_SC("NONE"),    _SC("OP_GREEDY"), _SC("OP_O
 #endif
 #define OP_GREEDY (MAX_CHAR + 1)  /*  * + ? {n} */
 #define OP_OR (MAX_CHAR + 2)
-#define OP_EXPR (MAX_CHAR + 3)       /* parentesis () */
-#define OP_NOCAPEXPR (MAX_CHAR + 4)  /* parentesis (?:) */
+#define OP_EXPR (MAX_CHAR + 3)       /* parenthesis () */
+#define OP_NOCAPEXPR (MAX_CHAR + 4)  /* parenthesis (?:) */
 #define OP_DOT (MAX_CHAR + 5)
 #define OP_CLASS (MAX_CHAR + 6)
 #define OP_CCLASS (MAX_CHAR + 7)
@@ -5313,7 +5313,7 @@ static void arg_parse_untagged(int argc, char** argv, struct arg_hdr** table, st
         }
     }
 
-    /* if a tenative error still remains at this point then register it as a proper error */
+    /* if a tentative error still remains at this point then register it as a proper error */
     if (errorlast) {
         arg_register_error(endtable, parentlast, errorlast, optarglast);
         optind++;
@@ -5384,7 +5384,7 @@ int arg_parse(int argc, char** argv, void** argtable) {
     /*
         Fill in the local copy of argv[]. We need a local copy
         because getopt rearranges argv[] which adversely affects
-        susbsequent parsing attempts.
+        subsequent parsing attempts.
         */
     for (i = 0; i < argc; i++)
         argvcopy[i] = argv[i];
@@ -5451,7 +5451,7 @@ static void arg_cat_option(char* dest, size_t ndest, const char* shortopts, cons
     if (shortopts) {
         char option[3];
 
-        /* note: option array[] is initialiazed dynamically here to satisfy   */
+        /* note: option array[] is initialized dynamically here to satisfy   */
         /* a deficiency in the watcom compiler wrt static array initializers. */
         option[0] = '-';
         option[1] = shortopts[0];
@@ -5509,7 +5509,7 @@ static void arg_cat_optionv(char* dest, size_t ndest, const char* shortopts, con
             /* "-a|-b|-c" */
             char shortopt[3];
 
-            /* note: shortopt array[] is initialiazed dynamically here to satisfy */
+            /* note: shortopt array[] is initialized dynamically here to satisfy */
             /* a deficiency in the watcom compiler wrt static array initializers. */
             shortopt[0] = '-';
             shortopt[1] = *c;
@@ -5881,7 +5881,7 @@ static void arg_print_formatted_ds(arg_dstr_t ds, const unsigned lmargin, const
  * Prints the glossary in strict GNU format.
  * Differences to arg_print_glossary() are:
  *   - wraps lines after 80 chars
- *   - indents lines without shortops
+ *   - indents lines without shortopts
  *   - does not accept formatstrings
  *
  * Contributed by Uli Fouquet
@@ -5956,7 +5956,7 @@ int arg_nullcheck(void** argtable) {
  * that entry were still allocated ok. Those subsequent allocations will not be
  * deallocated by arg_free().
  * Despite the unlikeliness of the problem occurring, and the even unlikelier event
- * that it has any deliterious effect, it is fixed regardless by replacing arg_free()
+ * that it has any deleterious effect, it is fixed regardless by replacing arg_free()
  * with the newer arg_freetable() function.
  * We still keep arg_free() for backwards compatibility.
  */

argtable3.h

@@ -87,7 +87,7 @@ typedef int(arg_comparefn)(const void* k1, const void* k2);
  * that particular arg_xxx arguments, performing post-parse checks, and
  * reporting errors.
  * These functions are private to the individual arg_xxx source code
- * and are the pointer to them are initiliased by that arg_xxx struct's
+ * and are the pointer to them are initialised by that arg_xxx struct's
  * constructor function. The user could alter them after construction
  * if desired, but the original intention is for them to be set by the
  * constructor and left unaltered.
@@ -95,7 +95,7 @@ typedef int(arg_comparefn)(const void* k1, const void* k2);
 typedef struct arg_hdr {
     char flag;             /* Modifier flags: ARG_TERMINATOR, ARG_HASVALUE. */
     const char* shortopts; /* String defining the short options */
-    const char* longopts;  /* String defiing the long options */
+    const char* longopts;  /* String defining the long options */
     const char* datatype;  /* Description of the argument data type */
     const char* glossary;  /* Description of the option as shown by arg_print_glossary function */
     int mincount;          /* Minimum number of occurences of this option accepted */

common.c

@@ -110,7 +110,7 @@ int make_listen_tfo(int s)
     return setsockopt(s, SOL_SOCKET, TCP_FASTOPEN, (char*)&qlen, sizeof(qlen));
 }
 
-/* Starts listening on a single address 
+/* Starts listening on a single address
  * Returns a socket filehandle, or dies with message in case of major error */
 int listen_single_addr(struct addrinfo* addr, int keepalive, int udp)
 {
@@ -262,7 +262,7 @@ int bind_peer(int fd, int fd_from)
     /* if the destination is the same machine, there's no need to do bind */
     if (is_same_machine(&from))
         return 0;
-    
+
 #ifndef IP_BINDANY /* use IP_TRANSPARENT */
     res = setsockopt(fd, IPPROTO_IP, IP_TRANSPARENT, &trans, sizeof(trans));
     CHECK_RES_DIE(res, "setsockopt IP_TRANSPARENT");
@@ -278,7 +278,26 @@ int bind_peer(int fd, int fd_from)
     }
 #endif /* IP_TRANSPARENT / IP_BINDANY */
     res = bind(fd, from.ai_addr, from.ai_addrlen);
-    CHECK_RES_RETURN(res, "bind", res);
+    if (res == -1) {
+        if (errno != EADDRINUSE) {
+            print_message(msg_system_error, "%s:%d:%s:%d:%s\n", __FILE__, __LINE__,
+                        "bind", errno, strerror(errno));
+            return res;
+        }
+
+        /*
+         * If there is more than one transparent mode proxy going on, such as
+         * using sslh as the target of stunnel also in transparent mode, then
+         * the (ip,port) combination will already be bound for the previous application.
+         * In that case, the best we can do is bind with a different port.
+         * This does mean the local server can't use the ident protocol as the port will
+         * have changed, but most people won't care.
+         * Also note that stunnel uses the same logic for the same situation.
+         */
+        ((struct sockaddr_in *)from.ai_addr)->sin_port = 0;
+        res = bind(fd, from.ai_addr, from.ai_addrlen);
+        CHECK_RES_RETURN(res, "bind", res);
+    }
 
     return 0;
 }
@@ -348,6 +367,7 @@ int connect_addr(struct connection *cnx, int fd_from, connect_blocking blocking)
 
             if (transparent) {
                 res = bind_peer(fd, fd_from);
+                if (res == -1) close(fd);
                 CHECK_RES_RETURN(res, "bind_peer", res);
             }
             res = connect(fd, a->ai_addr, a->ai_addrlen);
@@ -462,6 +482,7 @@ int fd2fd(struct queue *target_q, struct queue *from_q)
            return FD_NODATA;
 
        case ECONNRESET:
+       case ENOTSOCK:
        case EPIPE:
            return FD_CNXCLOSED;
        }
@@ -529,7 +550,8 @@ char* sprintaddr(char* buf, size_t size, struct addrinfo *a)
 }
 
 /* Turns a hostname and port (or service) into a list of struct addrinfo
- * returns 0 on success, -1 otherwise and logs error
+ * On success, returns 0 
+ * On failure, returns -1 or one of getaddrinfo() codes
  */
 int resolve_split_name(struct addrinfo **out, char* host, char* serv)
 {
@@ -555,7 +577,7 @@ int resolve_split_name(struct addrinfo **out, char* host, char* serv)
 
    res = getaddrinfo(host, serv, &hint, out);
    if (res)
-      print_message(msg_system_error, "%s `%s:%s'\n", gai_strerror(res), host, serv);
+      print_message(msg_system_error, "resolve_split_name: %s `%s:%s'\n", gai_strerror(res), host, serv);
    return res;
 }
 
@@ -847,4 +869,3 @@ void write_pid_file(const char* pidfile)
         exit(3);
     }
 }
-

common.h

@@ -5,6 +5,7 @@
  * enough for the macros to adapt (http://support.microsoft.com/kb/111855)
  */
 #ifdef __CYGWIN__
+#undef FD_SETSIZE
 #define FD_SETSIZE 4096
 #endif
 
@@ -112,7 +113,7 @@ struct connection {
     struct queue q[2];
 
     /* SOCK_DGRAM */
-    struct sockaddr client_addr; /* Contains the remote client address */
+    struct sockaddr_storage client_addr; /* Contains the remote client address */
     socklen_t addrlen;
 
     int local_endpoint; /* Contains the local address */
@@ -183,4 +184,8 @@ void start_shoveler(int);
 
 void main_loop(struct listen_endpoint *listen_sockets, int num_addr_listen);
 
+/* landlock.c */
+void setup_landlock(void);
+
+
 #endif

config.h.in

@@ -0,0 +1,9 @@
+
+
+#ifndef CONFIG_H
+/* Template for config.h, filled by `configure`. */
+
+/* Landlock sandboxing Linux LSM */
+#undef HAVE_LANDLOCK
+
+#endif

configure.ac

@@ -0,0 +1,9 @@
+
+dnl Use autoconf to generate the `configure` script from this and Makefile.in
+
+AC_INIT
+AC_CONFIG_HEADERS(config.h)
+AC_CONFIG_FILES([Makefile])
+
+AC_CHECK_HEADERS(linux/landlock.h, AC_DEFINE(HAVE_LANDLOCK), [])
+AC_OUTPUT

container-entrypoint.sh

@@ -0,0 +1,97 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL2-or-later
+#
+# Copyright (C) 2023 Olliver Schinagl <oliver@schinagl.nl>
+#
+# A beginning user should be able to docker run image bash (or sh) without
+# needing to learn about --entrypoint
+# https://github.com/docker-library/official-images#consistency
+
+set -eu
+
+bin='sslh'
+
+# run command if it is not starting with a "-" and is an executable in PATH
+if [ "${#}" -le 0 ] || \
+   [ "${1#-}" != "${1}" ] || \
+   [ -d "${1}" ] || \
+   ! command -v "${1}" > '/dev/null' 2>&1; then
+	entrypoint='true'
+fi
+
+unconfigure_iptables() { 
+	echo "Received SIG TERM/INT/KILL. Removing iptables / routing changes"
+
+	set +e # Don't exit if got error
+	set -x
+
+	iptables -t raw -D PREROUTING ! -i lo -d 127.0.0.0/8 -j DROP
+	iptables -t mangle -D POSTROUTING ! -o lo -s 127.0.0.0/8 -j DROP
+
+	iptables -t nat -D OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+	iptables -t mangle -D OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+	ip rule del fwmark 0x1 lookup 100
+	ip route del local 0.0.0.0/0 dev lo table 100
+
+
+	if [ $(cat /proc/sys/net/ipv6/conf/all/disable_ipv6) -eq 0 ]; then
+		ip6tables -t raw -D PREROUTING ! -i lo -d ::1/128 -j DROP
+		ip6tables -t mangle -D POSTROUTING ! -o lo -s ::1/128 -j DROP
+		ip6tables -t nat -D OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+		ip6tables -t mangle -D OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+		ip -6 rule del fwmark 0x1 lookup 100
+		ip -6 route del local ::/0 dev lo table 100
+	fi
+		
+	set -e
+	set +x
+}
+
+configure_iptables() {
+	echo "Configuring iptables and routing..."
+
+	set +e # Don't exit if got error
+	set -x
+	
+	iptables -t raw -A PREROUTING ! -i lo -d 127.0.0.0/8 -j DROP
+	iptables -t mangle -A POSTROUTING ! -o lo -s 127.0.0.0/8 -j DROP
+
+	iptables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN  -j CONNMARK --set-xmark 0x01/0x0f
+	iptables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+	ip rule add fwmark 0x1 lookup 100
+	ip route add local 0.0.0.0/0 dev lo table 100
+
+	if [ $(cat /proc/sys/net/ipv6/conf/all/disable_ipv6) -eq 0 ]; then
+		ip6tables -t raw -A PREROUTING ! -i lo -d ::1/128 -j DROP
+		ip6tables -t mangle -A POSTROUTING ! -o lo -s ::1/128 -j DROP
+		ip6tables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+		ip6tables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+		ip -6 rule add fwmark 0x1 lookup 100
+		ip -6 route add local ::/0 dev lo table 100
+	fi
+	
+	set -e
+	set +x
+}
+
+for _args in "${@}" ; do
+	if [ "${_args:-}" = '--transparent' ] ; then
+		echo '--transparent flag is set'
+		configure_iptables
+		trap unconfigure_iptables TERM INT KILL
+		break
+	fi
+done
+
+# Drop privileges and run as sslh user
+sslh_cmd="${entrypoint:+${bin}} ${@}"
+echo "Executing with user 'sslh': ${sslh_cmd}"
+
+exec su - sslh -c "${sslh_cmd}" &
+wait "${!}"
+
+exit 0

doc/FAQ.md

@@ -7,7 +7,7 @@ doesn't work, report how what was suggested here went.
 It's also worth reading [how to ask
 questions](http://www.catb.org/~esr/faqs/smart-questions.html)
 before posting on the mailing list or opening an issue in
-Github.
+GitHub.
 
 Getting more info
 =================

doc/INSTALL.md

@@ -1,3 +1,12 @@
+Pre-built binaries
+==================
+
+Docker images of `master` and of the tagged versions are
+available directly from [Github](https://github.com/yrutschle/sslh/pkgs/container/sslh).
+
+Windows binaries for Cygwin are graciouly produced by
+nono303 on his [repository](https://github.com/nono303/sslh).
+
 Compile and install
 ===================
 
@@ -79,6 +88,20 @@ of the Makefile:
 * `USELIBBSD` compiles support for updating the process name (as shown
   by `ps`).
 
+Generating the configuration parser
+-----------------------------------
+
+The configuration file and command line parser is generated
+by `conf2struct`, from `sslhconf.cfg`, which generates
+`sslh-conf.c` and `sslh-conf.h`. The resulting files are
+included in the source so `sslh` can be built without
+`conf2struct` installed.
+
+Further, to prevent build issues, `sslh-conf.[ch]` has no
+dependency to `sslhconf.cfg` in the Makefile.  In the event
+of adding configuration settings, they need to be
+regenerated using `make c2s`.
+
 Binaries
 --------
 

doc/README.Windows.md

@@ -0,0 +1,72 @@
+It is possible to run `sslh` on Windows. The `fork` model
+should be avoided as it is very inefficient on Windows, but
+`sslh-select` and `sslh-ev` both work with good performance
+(prefer the latter, however).
+
+
+The following script downloads the latest cygwin, the latest version of sslh, and then compiles and copies the binaries with dependancies to an output folder.
+
+It may be needed to correct it from time to time, but it works. I use it in a virtual machine.
+Just retrieve WGET.EXE from [https://eternallybored.org/misc/wget/](url) or git binaries.
+
+Copy the 3 files
+
+	GO.cmd
+	wget.exe
+	compile.sh
+	
+to C root folder, then execute **GO.cmd** with administrative rights.
+
+with **GO.cmd**
+
+	@ECHO OFF
+	CD /D "%~dp0"
+	
+	NET SESSION >NUL 2>&1
+	IF %ERRORLEVEL% NEQ 0 (
+	    ECHO Permission denied. This script must be run as an Administrator.
+	    ECHO:
+	    GOTO FIN
+	) ELSE (
+	    ECHO Running as Administrator.
+	    TIMEOUT /T 2 >NUL
+		wget --no-check-certificate https://www.cygwin.com/setup-x86_64.exe
+		IF NOT EXIST setup-x86_64.exe GOTO FIN
+		MKDIR C:\Z
+		setup-x86_64.exe -l C:\Z -s ftp://ftp.funet.fi/pub/mirrors/sourceware.org/pub/cygwin/ -q -P make -P git -P gcc-g++ -P autoconf -P automake -P libtool -P libpcre-devel -P libpcre2-devel -P bison -P libev-devel
+		MKDIR C:\cygwin64\home\user
+	COPY COMPILE.SH C:\cygwin64\home\user
+			START C:\cygwin64\bin\mintty.exe /bin/bash --login -i ~/compile.sh
+		START EXPLORER C:\zzSORTIE
+	)
+	:FIN
+	PAUSE
+	EXIT
+
+
+and **compile.sh**
+
+	# SAVE FILE TO UNIX FORMAT
+	# COPY IT IN C cygwin64 home user
+	git clone https://github.com/hyperrealm/libconfig.git
+	cd libconfig
+	autoreconf -fi
+	./configure
+	make
+	make install
+	cd ..
+	cp /usr/local/lib/libconfig.* /usr/lib
+	git clone https://github.com/yrutschle/sslh.git
+	cd sslh
+	make
+	cd ..
+	mkdir /cygdrive/c/zzSORTIE
+	cp ./sslh/sslh*.exe /cygdrive/c/zzSORTIE
+	cp /usr/local/bin/cygconfig-11.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygwin1.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygpcreposix-0.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygpcre-1.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygev-4.dll /cygdrive/c/zzSORTIE
+	cp /cygdrive/c/cygwin64/bin/cygpcre2-8-0.dll /cygdrive/c/zzSORTIE
+
+This method was contributed by lerenardo on [github](https://github.com/yrutschle/sslh/issues/196#issuecomment-1692805639).

doc/config.md

@@ -92,19 +92,15 @@ to the executable:
 
 	sudo setcap cap_net_bind_service,cap_net_raw+pe sslh-select
 
-Then you can run sslh-select as an unpriviledged user, e.g.:
+Then you can run sslh-select as an unprivileged user, e.g.:
 
 	sslh-select -p myname:443 --ssh localhost:22 --tls localhost:443
 
 Transparent proxy support
 -------------------------
 
-Transparent proxying allows the target server to see the
-original client IP address, i.e. `sslh` becomes invisible.
-This makes it easier to use the server's logs, and potential
-IP-based banning ability.
-
-Set up can get complicated, so it has its own [document](tproxy.md).
+Transparent proxying is described in its own
+[document](tproxy.md).
 
 Systemd Socket Activation
 -------------------------
@@ -167,7 +163,7 @@ This parses the /etc/sslh.cfg (or /etc/sslh/sslh.cfg file if that exists
 instead) configuration file and dynamically generates a socket file to use.
 
 This will also merge with any sslh.socket.d drop in configuration but will be 
-overriden by a /etc/systemd/system/sslh.socket file.
+overridden by a /etc/systemd/system/sslh.socket file.
 
 To use the generator place it in /usr/lib/systemd/system-generators and then
 call systemctl daemon-reload after any changes to /etc/sslh.cfg to generate 
@@ -196,6 +192,8 @@ will wait for incoming UDP packets, run the probes in the
 usual fashion, and forward packets to the appropriate
 target. `sslh` will then remember the association between
 remote host to target server for 60 seconds by default,
-which can be overriden with `udp_timeout`. This allows to
+which can be overridden with `udp_timeout`. This allows to
 process both single-datagram protocols such as DNS, and
 connection-based protocols such as QUIC.
+
+An example for supporting QUIC is shown in `example.cfg`.

doc/tproxy.md

@@ -60,7 +60,7 @@ this scheme -- let me know if you manage that:
 	ip rule add fwmark 0x1 lookup 100
 	ip route add local 0.0.0.0/0 dev lo table 100
 
-Tranparent proxying with IPv6 is similarly set up as follows:
+Transparent proxying with IPv6 is similarly set up as follows:
 
 	# Set route_localnet = 1 on all interfaces so that ssl can use "localhost" as destination
 	# Not sure if this is needed for ipv6 though

echosrv-conf.c

@@ -365,7 +365,7 @@ static int clcpy(config_type type, void* target, const void* cl_arg)
     return 0;
 }
 
-/* Copy the value of a string argument to arbitary memory
+/* Copy the value of a string argument to arbitrary memory
 * location that must be large enough, converting on the way
 * (i.e. CFG_INT gets atoi() and so on) */
 /* 0: success
@@ -862,7 +862,7 @@ static int set_target_fields(void* target_addr, struct compound_cl_arg* arg, con
             if (pmatch[pmatch_cnt].rm_so == -1) {
                 /* This should not happen as regexec() did
                 * match before, unless there is a
-                * discrepency between the regex and the
+                * discrepancy between the regex and the
                 * number of backreferences */
                 return 0;
             }
@@ -1155,7 +1155,7 @@ static void scalar_to_string(char** strp, config_setting_t* s)
 
 /* Typesets all the settings in a configuration as a
 * newly-allocated string. The string management is caller's
-* responsability. 
+* responsibility. 
 * Returns the number of scalars in the configuration */
 static int cfg_as_string(config_setting_t* parent, const char* path, char** strp)
 {

echosrv.c

@@ -1,6 +1,6 @@
 /* echosrv: a simple line echo server with optional prefix adding.
  *
- * echsrv --listen localhost6:1234 --prefix "ssl: "
+ * echosrv --listen localhost6:1234 --prefix "ssl: "
  *
  * This will bind to 1234, and echo every line pre-pending "ssl: ". This is
  * used for testing: we create several such servers with different prefixes,

gap.c

@@ -48,7 +48,10 @@ gap_array* gap_init(int len)
     gap->len = gap_len_alloc(elem_size);
     if (gap->len < len) gap->len = len;
     gap->array = malloc(gap->len * elem_size);
-    if (!gap->array) return NULL;
+    if (!gap->array) {
+        free(gap);
+        return NULL;
+    }
 
     for (int i = 0; i < gap->len; i++)
         gap->array[i] = NULL;
@@ -99,7 +102,7 @@ int gap_remove_ptr(gap_array* gap, void* ptr, int len)
     else
         return -1;
 
-    for (i = start; i < len; i++) {
+    for (i = start; i < len - 1; i++) {
         gap->array[i] = gap->array[i+1];
     }
 

gap.h

@@ -32,6 +32,11 @@ static inline int __attribute__((unused)) gap_set(gap_array* gap, int index, voi
 
 static inline void* __attribute__((unused)) gap_get(gap_array* gap, int index)
 {
+    /* sslh-ev routinely reads before it writes. It's not clear if it should be
+     * its job to check the length (and add a gap_getlen()), or if it should be
+     * gap_get()'s job. This will do for now */
+    if (index >= gap->len) return NULL;
+
     return gap->array[index];
 }
 

genver.sh

@@ -10,14 +10,14 @@ fi
 if [ ! -d .git ] || ! `(git status | grep -q "On branch") 2> /dev/null`; then
         # If we don't have git, we can't work out what
         # version this is. It must have been downloaded as a
-        # zip file. 
-        
+        # zip file.
+
         # If downloaded from the release page, the directory
         # has the version number.
         release=`pwd | sed s/.*sslh-// | grep "[[:digit:]]"`
-        
+
         if [ "x$release" = "x" ]; then
-            # If downloaded from the head, Github creates the
+            # If downloaded from the head, GitHub creates the
             # zip file with all files dated from the last
             # change: use the Makefile's modification time as a
             # release number
@@ -28,7 +28,7 @@ fi
 if [ -d .git ] && head=`git rev-parse --verify HEAD 2>/dev/null`; then
 	# generate the version info based on the tag
 	release=`(git describe --tags || git --describe || git describe --all --long) \
-		2>/dev/null | tr -d '\n'`
+		2>/dev/null | tr -s '/' '-' | tr -d '\n'`
 
 	# Are there uncommitted changes?
 	git update-index --refresh --unmerged > /dev/null

hashtest/run

@@ -5,7 +5,7 @@
 # Tests scripts are in *.tst files.
 # Corresponding output is put in *.out.
 # Reference output is put in *.ref.
-# Any discrepency will be reported!
+# Any discrepancy will be reported!
 
 use strict;
 

landlock.c

@@ -0,0 +1,156 @@
+/*
+ * Setup a sandbox using the Landlock LSM, if available.
+
+# Copyright (C) 2023  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be
+# useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+#
+*/
+
+#include "config.h"
+#include "log.h"
+
+#ifdef HAVE_LANDLOCK
+
+#define _GNU_SOURCE
+#include <linux/landlock.h>
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+
+/* Ubuntu 22.04 does not have this symbol */
+#ifndef LANDLOCK_ACCESS_FS_REFER
+#define LANDLOCK_ACCESS_FS_REFER			(1ULL << 13)
+#endif
+
+#ifndef landlock_create_ruleset
+static inline int
+landlock_create_ruleset(const struct landlock_ruleset_attr *const attr,
+			const size_t size, const __u32 flags)
+{
+	return syscall(__NR_landlock_create_ruleset, attr, size, flags);
+}
+#endif
+
+#ifndef landlock_add_rule
+static inline int landlock_add_rule(const int ruleset_fd,
+				    const enum landlock_rule_type rule_type,
+				    const void *const rule_attr,
+				    const __u32 flags)
+{
+	return syscall(__NR_landlock_add_rule, ruleset_fd, rule_type, rule_attr,
+		       flags);
+}
+#endif
+
+#ifndef landlock_restrict_self
+static inline int landlock_restrict_self(const int ruleset_fd,
+					 const __u32 flags)
+{
+	return syscall(__NR_landlock_restrict_self, ruleset_fd, flags);
+}
+#endif
+
+typedef enum {
+    LL_TREE,
+    LL_FILE
+} ll_obj_type;
+
+static int add_path_ro(int ruleset_fd, ll_obj_type otype, const char* path)
+{
+    int fd = open(path, O_PATH | O_CLOEXEC);
+    if (fd < 0) {
+        print_message(msg_config_error, "Landlock: Failed to open %s: %s\n", path, strerror(errno));
+        return -1;
+    }
+
+    struct landlock_path_beneath_attr path_beneath = {
+        .allowed_access = (otype == LL_TREE ? LANDLOCK_ACCESS_FS_READ_DIR : 0 ) |
+                          LANDLOCK_ACCESS_FS_READ_FILE,
+        .parent_fd = fd,
+    };
+
+    int res = landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH, &path_beneath, 0);
+    if (res) {
+        print_message(msg_config_error, "Landlock: Failed to update the ruleset with \"%s\": %s\n",
+                path, strerror(errno));
+        close(path_beneath.parent_fd);
+        return -1;
+    }
+
+    return 0;
+}
+
+
+void setup_landlock(void)
+{
+    __u64 restrict_rules = 
+        LANDLOCK_ACCESS_FS_EXECUTE |
+        LANDLOCK_ACCESS_FS_READ_FILE |
+        LANDLOCK_ACCESS_FS_READ_DIR |
+        LANDLOCK_ACCESS_FS_WRITE_FILE |
+        LANDLOCK_ACCESS_FS_REMOVE_DIR |
+        LANDLOCK_ACCESS_FS_REMOVE_FILE |
+        LANDLOCK_ACCESS_FS_MAKE_CHAR |
+        LANDLOCK_ACCESS_FS_MAKE_DIR |
+        LANDLOCK_ACCESS_FS_MAKE_REG |
+        LANDLOCK_ACCESS_FS_MAKE_SOCK |
+        LANDLOCK_ACCESS_FS_MAKE_FIFO |
+        LANDLOCK_ACCESS_FS_MAKE_BLOCK |
+        LANDLOCK_ACCESS_FS_MAKE_SYM |
+        LANDLOCK_ACCESS_FS_REFER;
+
+    struct landlock_ruleset_attr ruleset_attr = {
+        .handled_access_fs = restrict_rules
+    };
+
+    /* ruleset_addr.handled_access_fs contains all rights that will be restricted
+     * unless explicitly added */
+    int ruleset_fd = landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+    if (ruleset_fd < 0) {
+        print_message(msg_config_error, "Landlock: Failed to create a ruleset");
+        return;
+    }
+
+    /* Access to libraries, to be able to fork */
+    add_path_ro(ruleset_fd, LL_TREE, "/lib");
+    add_path_ro(ruleset_fd, LL_TREE, "/usr/lib");
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/ld.so.cache");  /* To avoid searching all libs... */
+
+    /* Files to resolve names (required when dynamic resolution is used) */
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/hosts");
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/resolv.conf");
+    add_path_ro(ruleset_fd, LL_FILE, "/etc/nsswitch.conf");
+
+    if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
+        print_message(msg_config_error, "Landlock: Failed to restrict privileges");
+        return;
+    }
+    if (landlock_restrict_self(ruleset_fd, 0)) {
+        print_message(msg_config_error, "Landlock: Failed to enforce ruleset");
+        return;
+    }
+    close(ruleset_fd);
+
+    print_message(msg_config, "Landlock: all restricted\n");
+}
+
+#else /* HAVE_LANDLOCK */
+void setup_landlock(void)
+{
+    print_message(msg_config, "Landlock: not built in\n");
+    return;
+}
+#endif /* HAVE_LANDLOCK */

log.c

@@ -107,10 +107,11 @@ void print_message(msg_info info, const char* str, ...)
 {
     va_list ap;
 
-    va_start(ap, str);
-
-    if ((*info.verbose & MSG_STDOUT) && ! cfg.inetd)
+    if ((*info.verbose & MSG_STDOUT) && ! cfg.inetd) {
+        va_start(ap, str);
         vfprintf(stderr, str, ap);
+        va_end(ap);
+    }
 
     if (*info.verbose & MSG_SYSLOG) {
         va_start(ap, str);
@@ -194,7 +195,11 @@ void log_connection(struct connection_desc* desc, const struct connection *cnx)
 
     if (!desc) {
         desc = &d;
-        get_connection_desc(desc, cnx);
+        if (!get_connection_desc(desc, cnx)) {
+            print_message(msg_connections, "%s: lost incoming connection\n",
+                          cnx->proto->name);
+            return;
+        }
     }
 
     print_message(msg_connections, "%s:connection from %s to %s forwarded from %s to %s\n",

probe.c

@@ -173,13 +173,13 @@ static int is_openvpn_protocol (const char*p,ssize_t len, struct sslhcfg_protoco
          * whereas the packet id is increased with every transmitted datagram.
          */
 
-        if (len <= OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_128))
+        if (len <= OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_128) + sizeof(uint32_t))
             return PROBE_NEXT;
 
         if (ntohl(*(uint32_t*)(p + OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_128))) <= 5u)
             return PROBE_MATCH;
 
-        if (len <= OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_160))
+        if (len <= OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_160) + sizeof(uint32_t))
             return PROBE_NEXT;
 
         if (ntohl(*(uint32_t*)(p + OVPN_HARD_RESET_PACKET_ID_OFFSET(OVPN_HMAC_160))) <= 5u)

scripts/etc.sysconfig.sslh

@@ -18,7 +18,7 @@
 #CONFIG=/etc/sslh.cfg
 
 #
-# Extra option to pass on comand line
+# Extra option to pass on command line
 # Those can supersede configuration file settings
 # 
 #OPTIONS=

scripts/fail2ban/sslh-ssh.conf

@@ -8,7 +8,7 @@
 # but many connection attempts from the same
 # origin is reason enough to block.
 #
-# Verion: 2014-03-28
+# Version: 2014-03-28
 
 [INCLUDES]
 

sslh-conf.c

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Sun Sep 11 21:43:25 2022. 
+ * on Tue Jan  2 21:25:47 2024. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2021  Yves Rutschle
@@ -471,6 +471,7 @@ struct arg_file* sslhcfg_conffile;
  	struct arg_str* sslhcfg_listen;
  	struct arg_str* sslhcfg_ssh;
  	struct arg_str* sslhcfg_tls;
+ 	struct arg_str* sslhcfg_ssl;
  	struct arg_str* sslhcfg_openvpn;
  	struct arg_str* sslhcfg_tinc;
  	struct arg_str* sslhcfg_wireguard;
@@ -1333,6 +1334,15 @@ static struct compound_cl_target sslhcfg_openvpn_targets [] = {
 	{ 0 }
 };
 
+static struct compound_cl_target sslhcfg_ssl_targets [] = {
+	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "tls" },
+	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
+	{ & table_sslhcfg_protocols[2], 2, .value.def_string = "0" },
+	{ & table_sslhcfg_protocols[10], 0, .value.def_int = 1 },
+	{ & table_sslhcfg_protocols[7], 0, .value.def_bool = 1 },
+	{ 0 }
+};
+
 static struct compound_cl_target sslhcfg_tls_targets [] = {
 	{ & table_sslhcfg_protocols[0], 0, .value.def_string = "tls" },
 	{ & table_sslhcfg_protocols[1], 1, .value.def_string = "0" },
@@ -1395,6 +1405,18 @@ static struct compound_cl_arg compound_cl_args[] = {
             .override_const = "tls",
         },
 
+        {   /* arg: ssl */
+            .regex =           "(.+):(\\w+)",
+            .arg_cl =          & sslhcfg_ssl,
+            .base_entry =      & table_sslhcfg [26],
+            .targets =         sslhcfg_ssl_targets,
+
+
+            .override_desc =   & table_sslhcfg_protocols [0],
+            .override_matchindex = 0,
+            .override_const = "tls",
+        },
+
         {   /* arg: openvpn */
             .regex =           "(.+):(\\w+)",
             .arg_cl =          & sslhcfg_openvpn,
@@ -2199,6 +2221,7 @@ int sslhcfg_cl_parse(int argc, char* argv[], struct sslhcfg_item* cfg)
  	sslhcfg_listen = arg_strn("p", "listen", "<host:port>", 0, 10, "Listen on host:port"),
  	sslhcfg_ssh = arg_strn(NULL, "ssh", "<host:port>", 0, 10, "Set up ssh target"),
  	sslhcfg_tls = arg_strn(NULL, "tls", "<host:port>", 0, 10, "Set up TLS/SSL target"),
+ 	sslhcfg_ssl = arg_strn(NULL, "ssl", "<host:port>", 0, 10, "Set up TLS/SSL target"),
  	sslhcfg_openvpn = arg_strn(NULL, "openvpn", "<host:port>", 0, 10, "Set up OpenVPN target"),
  	sslhcfg_tinc = arg_strn(NULL, "tinc", "<host:port>", 0, 10, "Set up tinc target"),
  	sslhcfg_wireguard = arg_strn(NULL, "wireguard", "<host:port>", 0, 10, "Set up WireGuard target"),

sslh-conf.h

@@ -1,5 +1,5 @@
 /* Generated by conf2struct (https://www.rutschle.net/tech/conf2struct/README)
- * on Sun Sep 11 21:43:25 2022. 
+ * on Tue Jan  2 21:25:47 2024. 
 
 # conf2struct: generate libconf parsers that read to structs
 # Copyright (C) 2018-2021  Yves Rutschle

sslh-ev.c

@@ -39,8 +39,6 @@ struct watchers {
 
     struct listen_endpoint* listen_sockets;
     gap_array* fd2ls;  /* Array indexed by file descriptor, pointing to listen_sockets */
-
-    int max_fd; /* legacy to be removed, still required for UDP */
 };
 
 static void cnx_read_cb(EV_P_ ev_io *w, int revents);
@@ -80,8 +78,6 @@ void watchers_add_read(watchers* w, int fd)
         gap_set(w->ev_ior, fd, io);
     }
     ev_io_start(loop, io);
-
-    if (fd > w->max_fd) w->max_fd = fd + 1;
 }
 
 void watchers_del_read(watchers* w, int fd)
@@ -101,8 +97,6 @@ void watchers_add_write(watchers* w, int fd)
         gap_set(w->ev_iow, fd, io);
     }
     ev_io_start(loop, io);
-
-    if (fd > w->max_fd) w->max_fd = fd + 1;
 }
 
 void watchers_del_write(watchers* w, int fd)

sslh-fork.c

@@ -164,6 +164,13 @@ void set_listen_procname(struct listen_endpoint *listen_socket)
 }
 
 
+/* At least MacOS does not know these two options, so define them to something
+ * equivalent for our use case */
+#ifndef ENONET
+#define ENONET EWOULDBLOCK
+#endif
+/* /MacOS kludge */
+
 /* TCP listener: connections, fork a child for each new connection 
  * IN: 
  *      endpoint: array of listening endpoint objects
@@ -177,6 +184,26 @@ void tcp_listener(struct listen_endpoint* endpoint, int num_endpoints, int activ
 
     while (1) {
         in_socket = accept(endpoint[active_endpoint].socketfd, 0, 0);
+        CHECK_RES_RETURN(in_socket, "accept", /*void*/ );
+        if (in_socket == -1) {
+            print_message(msg_system_error, "%s:%d:%s:%d:%s\n", 
+                          __FILE__, __LINE__, "accept", errno, strerror(errno));
+            switch(in_socket) {
+            case ENETDOWN:  /* accept(2) cites all these errnos as "you should retry" */
+            case EPROTO:
+            case ENOPROTOOPT:
+            case EHOSTDOWN:
+            case ENONET:
+            case EHOSTUNREACH:
+            case EOPNOTSUPP:
+            case ENETUNREACH:
+            case ECONNABORTED:
+                continue;
+
+            default:  /* Otherwise, it's something wrong in our parameters, we fail */
+                return;
+            }
+        }
         print_message(msg_fd, "accepted fd %d\n", in_socket);
 
         switch(fork()) {
@@ -223,6 +250,8 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
                 print_message(msg_config_error, "UDP not (yet?) supported in sslh-fork\n");
             else
                 tcp_listener(listen_sockets, num_addr_listen, i);
+
+            exit(0);
 	    break;
 
 	/* We're in the parent, we don't need to do anything */

sslh-main.c

@@ -60,20 +60,26 @@ static void printcaps(void) {
 
 static void printsettings(void)
 {
-    char buf[NI_MAXHOST];
+    char buf[NI_MAXHOST + 256]; /* 256 > " family %d %d" for reasonable ints */
     int i;
     struct sslhcfg_protocols_item *p;
     
     for (i = 0; i < cfg.protocols_len; i++ ) {
         p = &cfg.protocols[i];
+        strcpy(buf, "resolve on forward");
+        if (!p->resolve_on_forward) {
+            sprintaddr(buf, sizeof(buf), p->saddr);
+            int len = strlen(buf);
+            sprintf(buf+len, " family %d %d", 
+                    p->saddr->ai_family,
+                    p->saddr->ai_addr->sa_family);
+        }
         print_message(msg_config, 
-                      "%s addr: %s. libwrap service: %s log_level: %d family %d %d [%s] [%s] [%s]\n",
+                      "%s addr: %s. libwrap service: %s log_level: %d [%s] [%s] [%s]\n",
                       p->name, 
-                      sprintaddr(buf, sizeof(buf), p->saddr), 
+                      buf,
                       p->service,
                       p->log_level,
-                      p->saddr->ai_family,
-                      p->saddr->ai_addr->sa_family,
                       p->keepalive ? "keepalive" : "",
                       p->fork ? "fork" : "",
                       p->transparent ? "transparent" : ""
@@ -277,6 +283,7 @@ int main(int argc, char *argv[], char* envp[])
 
    if (cfg.user || cfg.chroot)
        drop_privileges(cfg.user, cfg.chroot);
+   setup_landlock();
 
    printcaps();
 

sslh-select.c

@@ -180,9 +180,9 @@ void main_loop(struct listen_endpoint listen_sockets[], int num_addr_listen)
         for (i = 0; i < fd_info.num_probing; i++) {
             struct connection* cnx = gap_get(fd_info.probing_list, i);
             if (!cnx || cnx->state != ST_PROBING) {
-                print_message(msg_int_error, "Inconsistent probing: cnx=%0xp\n", cnx);
+                print_message(msg_int_error, "Inconsistent probing: cnx=0x%p\n", cnx);
                 if (cnx)
-                    print_message(msg_int_error, "Inconsistent probing: state=%d\n", cnx);
+                    print_message(msg_int_error, "Inconsistent probing: state=%d\n", cnx->state);
                 exit(1);
             }
             if (cnx->probe_timeout < time(NULL)) {

sslhconf.cfg

@@ -186,6 +186,19 @@ cl_groups: (
         { path: "tfo_ok"; value: 1 }
         );
     },
+    # Redundant with the --tls setting before, for backwards compatibility
+    { name: "ssl"; pattern: "(.+):(\w+)"; description: "Set up TLS/SSL target";
+        list: "protocols";
+        override: "name";
+        argdesc: "<host:port>";
+        targets: (
+        { path: "name"; value: "tls" },
+        { path: "host"; value: "$1" },
+        { path: "port"; value: "$2" },
+        { path: "log_level"; value: 1 },
+        { path: "tfo_ok"; value: 1 }
+        );
+    },
     { name: "openvpn"; pattern: "(.+):(\w+)"; description: "Set up OpenVPN target";
         list: "protocols";
         override: "name";

systemd-sslh-generator.c

@@ -55,9 +55,12 @@ static int get_listen_from_conf(const char *filename, char **listen[]) {
                             config_setting_source_line(addr));
                     return -1;
                 } else {
-                    (*listen)[i] = malloc(strlen(resolve_listen(hostname, port)));
+                    char *resolved_listen = resolve_listen(hostname, port);
+
+                    (*listen)[i] = malloc(strlen(resolved_listen));
                     CHECK_ALLOC((*listen)[i], "malloc");
-                    strcpy((*listen)[i], resolve_listen(hostname, port));
+                    strcpy((*listen)[i], resolved_listen);
+                    free(resolved_listen);
                 }
             }
         }
@@ -125,6 +128,7 @@ static int gen_sslh_config(char *runtime_unit_dir) {
         strcpy(runtime_conf, runtime_unit_dir);
         strcat(runtime_conf, unit_file);
         runtime_conf_fd = fopen(runtime_conf, "w");
+        free(runtime_conf);
     }
 
 

t

@@ -396,7 +396,7 @@ if ($RB_RESOLVE_ADDRESS) {
     my $sslh_pid;
     if (!($sslh_pid = fork)) {
         my $user = (getpwuid $<)[0]; # Run under current username
-        exec "./sslh-select -v 3 -f -u $user --listen blahblah.dontexist:9000 --ssh $ssh_address --tls $ssl_address -P $pidfile";
+        exec "./sslh-select -v 3 -f -u $user --listen blahblah.nonexistent:9000 --ssh $ssh_address --tls $ssl_address -P $pidfile";
     }
     warn "spawned $sslh_pid\n";
     waitpid $sslh_pid, 0;

t_load

@@ -14,7 +14,7 @@
 use strict;
 use IO::Socket::INET6;
 use Data::Dumper;
-use Conf::Libconfig;
+use Conf::Libconfig 1.0.3;
 
 ## BEGIN TEST CONFIG
 
@@ -44,7 +44,7 @@ $conf->read_file("test.cfg");
 
 
 # Pick one address for TCP and one for UDP
-my @listen = @{$conf->fetch_array("listen")};
+my @listen = @{$conf->value("listen")};
 my ($sslh_tcp_address, $sslh_udp_address);
 
 foreach my $l (@listen) {
@@ -186,7 +186,7 @@ sub udp_client {
     }
 }
 
-foreach my $p (@{$conf->fetch_array("protocols")}) {
+foreach my $p (@{$conf->value("protocols")}) {
     if (!fork) {
         my $udp = $p->{is_udp} ? "--udp" : "";
         my $cmd = "./echosrv $udp -p $p->{host}:$p->{port} --prefix '$p->{name}: ' 2> /dev/null";
@@ -203,7 +203,7 @@ sleep 2; # Let echosrv's and sslh start
 my ($c_in, $c_out);
 pipe $c_in, $c_out;
 
-my @protocols = @{$conf->fetch_array("protocols")};
+my @protocols = @{$conf->value("protocols")};
 
 if (!fork) {
     # Process that starts all the clients

tcp-listener.c

@@ -67,14 +67,16 @@ static void shovel(struct connection *cnx, int active_fd, struct loop_info* fd_i
 }
 
 
-/* Returns the queue index that contains the specified file descriptor */
+/* Returns the queue index that contains the specified file descriptor.
+ * This is called by the *_process functions, which got cnx from the fd, so it
+ * is impossible for fd to not be cnx, hence we die if it happens */
 static int active_queue(struct connection* cnx, int fd)
 {
     if (cnx->q[0].fd == fd) return 0;
     if (cnx->q[1].fd == fd) return 1;
 
     print_message(msg_int_error, "file descriptor %d not found in connection object\n", fd);
-    return -1;
+    exit(1);
 }
 
 /* Process a TCP read event on the specified file descriptor */
@@ -156,13 +158,9 @@ static int connect_queue(struct connection* cnx,
         log_connection(NULL, cnx);
         flush_deferred(q);
         if (q->deferred_data) {
-            /*
-            FD_SET(q->fd, &fd_info->watchers->fds_w);
-            FD_CLR(cnx->q[0].fd, &fd_info->watchers->fds_r); */
             watchers_add_write(fd_info->watchers, q->fd);
             watchers_del_read(fd_info->watchers, cnx->q[0].fd);
         }
-        /* FD_SET(q->fd, &fd_info->watchers->fds_r); */
         watchers_add_read(fd_info->watchers, q->fd);
         collection_add_fd(fd_info->collection, cnx, q->fd);
         return q->fd;

tcp-probe.c

@@ -65,6 +65,7 @@ static void tcp_protocol_list_init(void)
         if (!p->is_udp) {
             tcp_protocols_len++;
             tcp_protocols = realloc(tcp_protocols, tcp_protocols_len * sizeof(*tcp_protocols));
+            CHECK_ALLOC(tcp_protocols, "realloc");
             tcp_protocols[tcp_protocols_len-1] = p;
         }
     }

test.cfg

@@ -42,7 +42,7 @@ listen:
  
 protocols:
 (
-     { name: "ssh";  host: "localhost"; port: "9000"; fork: true; transparent: true; },
+     { name: "ssh";  host: "localhost"; port: "9000"; fork: true; transparent: true; resolve_on_forward: true; },
      { name: "socks5";  host: "localhost"; port: "9001";  },
      { name: "http";  host: "localhost"; port: "9002";  },
      { name: "tinc";  host: "localhost"; port: "9003"; },
@@ -53,6 +53,7 @@ protocols:
      { name: "regex"; host: "ip4-localhost"; is_udp: true; port: "9020";
          udp_timeout: 30;
          regex_patterns: [ "^foo" ];
+         resolve_on_forward: true;
      },
      { name: "regex"; host: "localhost"; port: "9011";
         regex_patterns: [ "^foo", "^bar" ];

udp-listener.c

@@ -36,10 +36,10 @@
 
 static int cnx_cmp(struct connection* cnx1, struct connection* cnx2)
 {
-    struct sockaddr* addr1 = &cnx1->client_addr;
+    struct sockaddr_storage* addr1 = &cnx1->client_addr;
     socklen_t addrlen1 = cnx1->addrlen;
 
-    struct sockaddr* addr2 = &cnx2->client_addr;
+    struct sockaddr_storage* addr2 = &cnx2->client_addr;
     socklen_t addrlen2 = cnx2->addrlen;
 
     if (addrlen1 != addrlen2) return -1;
@@ -52,13 +52,13 @@ static int cnx_cmp(struct connection* cnx1, struct connection* cnx2)
  * lowest bytes of remote port */
 static int hash_make_key(hash_item new)
 {
-    struct sockaddr* addr = &new->client_addr;
+    struct sockaddr_storage* addr = &new->client_addr;
     //socklen_t addrlen = new->addrlen;
     struct sockaddr_in* addr4;
     struct sockaddr_in6* addr6;
     int out;
 
-    switch (addr->sa_family) {
+    switch (((struct sockaddr*)addr)->sa_family) {
     case AF_INET:
         addr4 = (struct sockaddr_in*)addr;
         out = addr4->sin_port;
@@ -86,13 +86,14 @@ static void udp_protocol_list_init(void)
         if (p->is_udp) {
             udp_protocols_len++;
             udp_protocols = realloc(udp_protocols, udp_protocols_len * sizeof(*udp_protocols));
+            CHECK_ALLOC(udp_protocols, "realloc");
             udp_protocols[udp_protocols_len-1] = p;
         }
     }
 }
 
 /* Configuration sanity check for UDP:
- * - If there is a listening addres, there must be at least one target
+ * - If there is a listening address, there must be at least one target
  */
 static void udp_sanity_check(void)
 {
@@ -129,7 +130,7 @@ void udp_init(struct loop_info* fd_info)
  * If yes, returns file descriptor of connection
  * If not, returns -1
  * */
-static int known_source(hash* h, struct sockaddr* addr, socklen_t addrlen)
+static int known_source(hash* h, struct sockaddr_storage* addr, socklen_t addrlen)
 {
     struct connection search;
     search.client_addr = *addr;
@@ -221,6 +222,28 @@ static void mark_active(struct connection* cnx)
 }
 
 
+/* Creates a new non-blocking socket */
+static int nonblocking_socket(struct sslhcfg_protocols_item* proto)
+{
+    int res;
+
+    if (proto->resolve_on_forward) {
+        res = resolve_split_name(&(proto->saddr), proto->host,
+                                 proto->port);
+        if (res) return -1;
+    }
+
+    int out = socket(proto->saddr->ai_family, SOCK_DGRAM, 0);
+    res = set_nonblock(out);
+    if (res == -1) {
+        print_message(msg_system_error, "%s:%d:%s:%d:%s\n", __FILE__, __LINE__, "udp:socket:nonblock", errno, strerror(errno));
+        close(out);
+        return -1;
+    }
+    return out;
+}
+
+
 /* Process UDP coming from outside (client towards server)
  * If it's a new source, probe; otherwise, forward to previous target 
  * Returns: newly allocate connections, for new connections
@@ -229,7 +252,7 @@ static void mark_active(struct connection* cnx)
 struct connection* udp_c2s_forward(int sockfd, struct loop_info* fd_info)
 {
     char addr_str[NI_MAXHOST+1+NI_MAXSERV+1];
-    struct sockaddr src_addr;
+    struct sockaddr_storage src_addr;
     struct addrinfo addrinfo;
     struct sslhcfg_protocols_item* proto;
     cnx_collection* collection = fd_info->collection;
@@ -237,7 +260,7 @@ struct connection* udp_c2s_forward(int sockfd, struct loop_info* fd_info)
     ssize_t len;
     socklen_t addrlen;
     int res, target, out = -1;
-    char data[65536]; /* Theoritical max is 65507 (https://en.wikipedia.org/wiki/User_Datagram_Protocol).
+    char data[65536]; /* Theoretical max is 65507 (https://en.wikipedia.org/wiki/User_Datagram_Protocol).
                          This will do.  Dynamic allocation is possible with the MSG_PEEK flag in recvfrom(2), but that'd imply
                          malloc/free overhead for each packet, when really 64K is not that much */
 
@@ -245,13 +268,13 @@ struct connection* udp_c2s_forward(int sockfd, struct loop_info* fd_info)
     udp_timeouts(fd_info);
 
     addrlen = sizeof(src_addr);
-    len = recvfrom(sockfd, data, sizeof(data), 0, &src_addr, &addrlen);
+    len = recvfrom(sockfd, data, sizeof(data), 0, (struct sockaddr*) &src_addr, &addrlen);
     if (len < 0) {
         perror("recvfrom");
         return NULL;
     }
     target = known_source(fd_info->hash_sources, &src_addr, addrlen);
-    addrinfo.ai_addr = &src_addr;
+    addrinfo.ai_addr = (struct sockaddr*) &src_addr;
     addrinfo.ai_addrlen = addrlen;
     print_message(msg_probe_info, "received %ld UDP from %d:%s\n", 
                   len, target, sprintaddr(addr_str, sizeof(addr_str), &addrinfo));
@@ -266,9 +289,8 @@ struct connection* udp_c2s_forward(int sockfd, struct loop_info* fd_info)
             return NULL;
         }
 
-        out = socket(proto->saddr->ai_family, SOCK_DGRAM, 0);
-        res = set_nonblock(out);
-        CHECK_RES_RETURN(res, "udp:socket:nonblock", NULL);
+        out = nonblocking_socket(proto);
+        if (out == -1) return NULL;
         struct connection* cnx = collection_alloc_cnx_from_fd(collection, out);
         if (!cnx) return NULL;
         target = out;
@@ -281,7 +303,7 @@ struct connection* udp_c2s_forward(int sockfd, struct loop_info* fd_info)
 
         res = new_source(fd_info->hash_sources, cnx);
         if (res == -1) {
-            print_message(msg_connections_error, "Out of hash space for new incoming UDP connection -- increaѕe udp_max_connections");
+            print_message(msg_connections_error, "Out of hash space for new incoming UDP connection -- increase udp_max_connections");
             collection_remove_cnx(collection, cnx);
             return NULL;
         }
@@ -308,7 +330,7 @@ void udp_s2c_forward(struct connection* cnx)
     if ((res == -1) && ((errno == EAGAIN) || (errno == EWOULDBLOCK))) return;
     CHECK_RES_DIE(res, "udp_listener/recvfrom");
     res = sendto(cnx->local_endpoint, data, res, 0,
-                 &cnx->client_addr, cnx->addrlen);
+                 (struct sockaddr*)&cnx->client_addr, cnx->addrlen);
     mark_active(cnx);
 }