Refactor tls code to support ucspi-tls

 That includes:
 - new architecture: the tls binary is now a child of the app
instead of the other way around
 - the sbearssl_run engine now takes a post-handshake callback.
This allows s6-tlsc and s6-tlsd to only exec into the app when
the handshake succeeds (which was already the case with libressl).
 - new binaries s6-tlsc-io and s6-tlsd-io encapsulate the crypto
code; they init and run the engine, connecting to 4 already open
fds (stdin/stdout = network, argv[1] and argv[2] = local)
 - s6-tlsc is now a simple wrapper around s6-tlsc-io
 - s6-tlsd is now a simple wrapper around s6-tlsd-io
 - new binary: s6-ucspitlsd, which is also a wrapper around
s6-tlsd-io, but differently: the parent execs the app which should
be ucspi-tls-aware, the child waits for a command from the parent
and execs into s6-tlsd-io if it receives it.

16 files changed, 654 insertions, 98 deletions

diff --git a/src/conn-tools/deps-exe/s6-tlsc b/src/conn-tools/deps-exe/s6-tlsc
index 6e89a02..37405fd 100644
--- a/src/conn-tools/deps-exe/s6-tlsc
+++ b/src/conn-tools/deps-exe/s6-tlsc
@@ -1,6 +1,2 @@
-${LIBCRYPTOSUPPORT}
+libs6tls.a.xyzzy
 -lskarnet
-${CRYPTO_LIB}
-${SOCKET_LIB}
-${SPAWN_LIB}
-${SYSCLOCK_LIB}
diff --git a/src/conn-tools/deps-exe/s6-tlsc-io b/src/conn-tools/deps-exe/s6-tlsc-io
new file mode 100644
index 0000000..3e2653d
--- /dev/null
+++ b/src/conn-tools/deps-exe/s6-tlsc-io
@@ -0,0 +1,5 @@
+${LIBCRYPTOSUPPORT}
+-lskarnet
+${CRYPTO_LIB}
+${SOCKET_LIB}
+${SYSCLOCK_LIB}
diff --git a/src/conn-tools/deps-exe/s6-tlsd b/src/conn-tools/deps-exe/s6-tlsd
index 6e89a02..37405fd 100644
--- a/src/conn-tools/deps-exe/s6-tlsd
+++ b/src/conn-tools/deps-exe/s6-tlsd
@@ -1,6 +1,2 @@
-${LIBCRYPTOSUPPORT}
+libs6tls.a.xyzzy
 -lskarnet
-${CRYPTO_LIB}
-${SOCKET_LIB}
-${SPAWN_LIB}
-${SYSCLOCK_LIB}
diff --git a/src/conn-tools/deps-exe/s6-tlsd-io b/src/conn-tools/deps-exe/s6-tlsd-io
new file mode 100644
index 0000000..3e2653d
--- /dev/null
+++ b/src/conn-tools/deps-exe/s6-tlsd-io
@@ -0,0 +1,5 @@
+${LIBCRYPTOSUPPORT}
+-lskarnet
+${CRYPTO_LIB}
+${SOCKET_LIB}
+${SYSCLOCK_LIB}
diff --git a/src/conn-tools/deps-exe/s6-ucspitlsd b/src/conn-tools/deps-exe/s6-ucspitlsd
new file mode 100644
index 0000000..ac1b327
--- /dev/null
+++ b/src/conn-tools/deps-exe/s6-ucspitlsd
@@ -0,0 +1,3 @@
+libs6tls.a.xyzzy
+-lskarnet
+${SOCKET_LIB}
diff --git a/src/conn-tools/deps-lib/s6tls b/src/conn-tools/deps-lib/s6tls
new file mode 100644
index 0000000..ad78cfd
--- /dev/null
+++ b/src/conn-tools/deps-lib/s6tls
@@ -0,0 +1,4 @@
+s6tls_drop.o
+s6tls_exec_tlscio.o
+s6tls_exec_tlsdio.o
+s6tls_wait_and_exec_app.o
diff --git a/src/conn-tools/s6-tlsc-io.c b/src/conn-tools/s6-tlsc-io.c
new file mode 100644
index 0000000..79dd25d
--- /dev/null
+++ b/src/conn-tools/s6-tlsc-io.c
@@ -0,0 +1,128 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include <skalibs/gccattributes.h>
+#include <skalibs/types.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/tai.h>
+#include <skalibs/env.h>
+#include <skalibs/sig.h>
+#include <skalibs/djbunix.h>
+
+#include <s6-networking/config.h>
+
+#define HANDSHAKE_BANNER "SSL_PROTOCOL=TLSv1\0"
+
+static inline void doit (int *, tain_t const *tto, uint32_t, uint32_t, unsigned int, char const *, unsigned int) gccattr_noreturn ;
+
+#ifdef S6_NETWORKING_USE_TLS
+
+#include <s6-networking/stls.h>
+
+static inline void doit (int *fds, tain_t const *tto, uint32_t preoptions, uint32_t options, unsigned int verbosity, char const *servername, unsigned int notif)
+{
+  struct tls *ctx = stls_client_init_and_handshake(fds + 2, preoptions, servername) ;
+  if (notif)
+  {
+    if (allwrite(notif, HANDSHAKE_BANNER, sizeof(HANDSHAKE_BANNER)) < sizeof(HANDSHAKE_BANNER))
+      strerr_diefu1sys(111, "write post-handshake data") ;
+    fd_close(notif) ;
+  }
+  stls_run(ctx, fds, tto, options, verbosity) ;
+}
+
+#else
+#ifdef S6_NETWORKING_USE_BEARSSL
+
+#include <skalibs/random.h>
+
+#include <s6-networking/sbearssl.h>
+
+static int handshake_cb_nop (br_ssl_engine_context *ctx, sbearssl_handshake_cb_context_t *cbarg)
+{
+  (void)ctx ;
+  (void)cbarg ;
+  return 1 ;
+}
+
+static int handshake_cb_sendvars (br_ssl_engine_context *ctx, sbearssl_handshake_cb_context_t *cbarg)
+{
+  if (allwrite(cbarg->notif, HANDSHAKE_BANNER, sizeof(HANDSHAKE_BANNER)) < sizeof(HANDSHAKE_BANNER))
+    return 0 ;
+  fd_close(cbarg->notif) ;
+  return 1 ;
+}
+
+static inline void doit (int *fds, tain_t const *tto, uint32_t preoptions, uint32_t options, unsigned int verbosity, char const *servername, unsigned int notif)
+{
+  if (ndelay_on(fds[0]) < 0 || ndelay_on(fds[1]) < 0)
+    strerr_diefu1sys(111, "set local fds non-blocking") ;
+  if (!random_init()) strerr_diefu1sys(111, "initialize random device") ;
+  sbearssl_client_init_and_run(fds, tto, preoptions, options, verbosity, servername, notif ? &handshake_cb_sendvars : &handshake_cb_nop, notif) ;
+}
+
+#else
+
+#error No SSL backend configured.
+
+#endif
+#endif
+
+
+#define USAGE "s6-tlsc-io [ -v verbosity ] [ -d notif ] [ -S | -s ] [ -Y | -y ] [ -K timeout ] [ -k servername ] fdr fdw"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  char const *servername = 0 ;
+  tain_t tto ;
+  int fds[4] = { 0, 1, 0, 1 } ;
+  unsigned int verbosity = 1 ;
+  unsigned int notif = 0 ;
+  uint32_t preoptions = 0 ;
+  uint32_t options = 1 ;
+
+  PROG = "s6-tlsc-io" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    unsigned int t = 0 ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "d:SsYyv:K:k:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 'd' : if (!uint0_scan(l.arg, &notif)) dieusage() ; break ;
+        case 'S' : options &= ~1 ; break ;
+        case 's' : options |= 1 ; break ;
+        case 'Y' : preoptions &= ~1 ; break ;
+        case 'y' : preoptions |= 1 ; break ;
+        case 'K' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
+        case 'k' : servername = l.arg ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+    if (t) tain_from_millisecs(&tto, t) ; else tto = tain_infinite_relative ;
+  }
+  if (argc < 2) dieusage() ;
+  {
+    unsigned int u ;
+    if (!uint0_scan(argv[0], &u)) dieusage() ;
+    fds[0] = u ;
+    if (!uint0_scan(argv[1], &u)) dieusage() ;
+    fds[1] = u ;
+  }
+
+  if (ndelay_on(0) < 0 || ndelay_on(1) < 0)
+    strerr_diefu1sys(111, "set stdin/stdout non-blocking") ;
+  if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+  tain_now_set_stopwatch_g() ;
+  doit(fds, &tto, preoptions, options, verbosity, servername, notif) ;
+}
diff --git a/src/conn-tools/s6-tlsc.c b/src/conn-tools/s6-tlsc.c
index d9df81c..6431ccb 100644
--- a/src/conn-tools/s6-tlsc.c
+++ b/src/conn-tools/s6-tlsc.c
@@ -2,67 +2,63 @@
 
 #include <stdint.h>
 #include <unistd.h>
-#include <errno.h>
+#include <fcntl.h>
+
+#include <skalibs/gccattributes.h>
 #include <skalibs/types.h>
 #include <skalibs/sgetopt.h>
 #include <skalibs/strerr2.h>
-#include <skalibs/tai.h>
 #include <skalibs/env.h>
 #include <skalibs/djbunix.h>
-#include <s6-networking/config.h>
-
-#ifdef S6_NETWORKING_USE_TLS
-
-#include <s6-networking/stls.h>
-#define s6tlsc stls_s6tlsc
-
-#else
-#ifdef S6_NETWORKING_USE_BEARSSL
-
-#include <s6-networking/sbearssl.h>
-#define s6tlsc sbearssl_s6tlsc
-
-#else
-
-#error No SSL backend configured.
-
-#endif
-#endif
 
+#include "s6tls-internal.h"
 
 #define USAGE "s6-tlsc [ -S | -s ]  [ -Y | -y ] [ -v verbosity ] [ -K timeout ] [ -k servername ] [ -Z | -z ] [ -6 rfd ] [ -7 wfd ] prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
-int main (int argc, char const *const *argv, char const *const *envp)
+static void child (int const [3][2], int, int, uint32_t, unsigned int, unsigned int, char const *) gccattr_noreturn ;
+static void child (int const p[3][2], int fdr, int fdw, uint32_t options, unsigned int verbosity, unsigned int kimeout, char const *servername)
+{
+  int fds[3] = { p[0][0], p[1][1], p[2][1] } ;
+  PROG = "s6-tlsc (child)" ;
+  s6tls_drop() ;
+  close(p[2][0]) ;
+  close(p[0][1]) ;
+  close(p[1][0]) ;
+  if (fd_move(0, fdr) < 0 || fd_move(1, fdw) < 0)
+    strerr_diefu1sys(111, "move network fds to stdin/stdout") ;
+  s6tls_exec_tlscio(fds, options, verbosity, kimeout, servername) ;
+}
+
+int main (int argc, char const *const *argv)
 {
+  int fds[2] = { 6, 7 } ;
   char const *servername = 0 ;
-  tain_t tto ;
   unsigned int verbosity = 1 ;
-  uid_t uid = 0 ;
-  gid_t gid = 0 ;
-  uint32_t preoptions = 2 ;
-  uint32_t options = 1 ;
-  int fds[2] = { 6, 7 } ;
+  unsigned int kimeout = 0 ;
+  int p[3][2] ;
+  uint32_t options = 0 ;
+  int cleanenv = 1 ;
+  pid_t pid ;
 
   PROG = "s6-tlsc" ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
-    unsigned int t = 0 ;
     for (;;)
     {
       int opt = subgetopt_r(argc, argv, "SsYyv:K:k:Zz6:7:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
-        case 'S' : options &= ~(uint32_t)1 ; break ;
-        case 's' : options |= 1 ; break ;
-        case 'Y' : preoptions &= ~(uint32_t)1 ; break ;
-        case 'y' : preoptions |= 1 ; break ;
+        case 'S' : options &= ~4 ; break ;
+        case 's' : options |= 4 ; break ;
+        case 'Y' : options &= ~1 ; break ;
+        case 'y' : options |= 1 ; break ;
         case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
-        case 'K' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
+        case 'K' : if (!uint0_scan(l.arg, &kimeout)) dieusage() ; break ;
         case 'k' : servername = l.arg ; break ;
-        case 'Z' : preoptions &= ~(uint32_t)2 ; break ;
-        case 'z' : preoptions |= 2 ; break ;
+        case 'Z' : cleanenv = 0 ; break ;
+        case 'z' : cleanenv = 1 ; break ;
         case '6' :
         {
           unsigned int fd ;
@@ -81,18 +77,20 @@ int main (int argc, char const *const *argv, char const *const *envp)
       }
     }
     argc -= l.ind ; argv += l.ind ;
-    if (t) tain_from_millisecs(&tto, t) ; else tto = tain_infinite_relative ;
   }
   if (!argc) dieusage() ;
-
-  if (!getuid())
+  fd_sanitize() ;
+  if (fcntl(fds[0], F_GETFD) < 0 || fcntl(fds[1], F_GETFD) < 0)
+    strerr_diefu1sys(111, "check network fds") ;
+  if (pipe(p[0]) < 0 || pipe(p[1]) < 0 || pipe(p[2]) < 0)
+    strerr_diefu1sys(111, "pipe") ;
+  pid = fork() ;
+  switch (pid)
   {
-    char const *x = env_get2(envp, "TLS_UID") ;
-    if (x && !uid0_scan(x, &uid)) strerr_dieinvalid(100, "TLS_UID") ;
-    x = env_get2(envp, "TLS_GID") ;
-    if (x && !gid0_scan(x, &gid)) strerr_dieinvalid(100, "TLS_GID") ;
+    case -1 : strerr_diefu1sys(111, "fork") ;
+    case 0 : child(p, fds[0], fds[1], options, verbosity, kimeout, servername) ;
+    default : break ;
   }
 
-  tain_now_set_stopwatch_g() ;
-  return s6tlsc(argv, envp, &tto, preoptions, options, uid, gid, verbosity, servername, fds) ;
+  s6tls_wait_and_exec_app(argv, p, pid, fds[0], fds[1], cleanenv ? 1 : 0) ;
 }
diff --git a/src/conn-tools/s6-tlsd-io.c b/src/conn-tools/s6-tlsd-io.c
new file mode 100644
index 0000000..0b42b3b
--- /dev/null
+++ b/src/conn-tools/s6-tlsd-io.c
@@ -0,0 +1,126 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include <skalibs/gccattributes.h>
+#include <skalibs/types.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/sig.h>
+#include <skalibs/tai.h>
+#include <skalibs/env.h>
+#include <skalibs/djbunix.h>
+
+#include <s6-networking/config.h>
+
+#define HANDSHAKE_BANNER "SSL_PROTOCOL=TLSv1\0"
+
+static inline void doit (int *, tain_t const *tto, uint32_t, uint32_t, unsigned int, unsigned int) gccattr_noreturn ;
+
+#ifdef S6_NETWORKING_USE_TLS
+
+#include <s6-networking/stls.h>
+
+static inline void doit (int *fds, tain_t const *tto, uint32_t preoptions, uint32_t options, unsigned int verbosity, unsigned int notif)
+{
+  struct tls *ctx = stls_server_init_and_handshake(fds + 2, preoptions) ;
+  if (notif)
+  {
+    if (allwrite(notif, HANDSHAKE_BANNER, sizeof(HANDSHAKE_BANNER)) < sizeof(HANDSHAKE_BANNER))
+      strerr_diefu1sys(111, "write post-handshake data") ;
+    fd_close(notif) ;
+  }
+  stls_run(ctx, fds, tto, options, verbosity) ;
+}
+
+#else
+#ifdef S6_NETWORKING_USE_BEARSSL
+
+#include <skalibs/random.h>
+
+#include <s6-networking/sbearssl.h>
+
+static int handshake_cb_nop (br_ssl_engine_context *ctx, sbearssl_handshake_cb_context_t *cbarg)
+{
+  (void)ctx ;
+  (void)cbarg ;
+  return 1 ;
+}
+
+static int handshake_cb_sendvars (br_ssl_engine_context *ctx, sbearssl_handshake_cb_context_t *cbarg)
+{
+  if (allwrite(cbarg->notif, HANDSHAKE_BANNER, sizeof(HANDSHAKE_BANNER)) < sizeof(HANDSHAKE_BANNER))
+    return 0 ;
+  fd_close(cbarg->notif) ;
+  return 1 ;
+}
+
+static inline void doit (int *fds, tain_t const *tto, uint32_t preoptions, uint32_t options, unsigned int verbosity, unsigned int notif)
+{
+  if (ndelay_on(fds[0]) < 0 || ndelay_on(fds[1]) < 0)
+    strerr_diefu1sys(111, "set local fds non-blocking") ;
+  if (!random_init()) strerr_diefu1sys(111, "initialize random device") ;
+  sbearssl_server_init_and_run(fds, tto, preoptions, options, verbosity, notif ? &handshake_cb_sendvars : &handshake_cb_nop, notif) ;
+}
+
+#else
+
+#error No SSL backend configured.
+
+#endif
+#endif
+
+
+#define USAGE "s6-tlsd-io [ -v verbosity ] [ -d notif ] [ -S | -s ] [ -Y | -y ] [ -K timeout ] fdr fdw"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  tain_t tto ;
+  int fds[4] = { 0, 1, 0, 1 } ;
+  unsigned int verbosity = 1 ;
+  unsigned int notif = 0 ;
+  uint32_t preoptions = 0 ;
+  uint32_t options = 1 ;
+
+  PROG = "s6-tlsd-io" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    unsigned int t = 0 ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "d:SsYyv:K:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 'd' : if (!uint0_scan(l.arg, &notif)) dieusage() ; break ;
+        case 'S' : options &= ~1 ; break ;
+        case 's' : options |= 1 ; break ;
+        case 'Y' : preoptions |= 1 ; preoptions &= ~2 ; break ;
+        case 'y' : preoptions |= 3 ; break ;
+        case 'K' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+    if (t) tain_from_millisecs(&tto, t) ; else tto = tain_infinite_relative ;
+  }
+  if (argc < 2) dieusage() ;
+  {
+    unsigned int u ;
+    if (!uint0_scan(argv[0], &u)) dieusage() ;
+    fds[0] = u ;
+    if (!uint0_scan(argv[1], &u)) dieusage() ;
+    fds[1] = u ;
+  }
+
+  if (ndelay_on(0) < 0 || ndelay_on(1) < 0)
+    strerr_diefu1sys(111, "set stdin/stdout non-blocking") ;
+  if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+  tain_now_set_stopwatch_g() ;
+  doit(fds, &tto, preoptions, options, verbosity, notif) ;
+}
diff --git a/src/conn-tools/s6-tlsd.c b/src/conn-tools/s6-tlsd.c
index 923ac47..e26ba49 100644
--- a/src/conn-tools/s6-tlsd.c
+++ b/src/conn-tools/s6-tlsd.c
@@ -2,79 +2,73 @@
 
 #include <stdint.h>
 #include <unistd.h>
+
+#include <skalibs/gccattributes.h>
 #include <skalibs/types.h>
 #include <skalibs/sgetopt.h>
 #include <skalibs/strerr2.h>
-#include <skalibs/tai.h>
 #include <skalibs/env.h>
 #include <skalibs/djbunix.h>
-#include <s6-networking/config.h>
-
-#ifdef S6_NETWORKING_USE_TLS
-
-#include <s6-networking/stls.h>
-#define s6tlsd stls_s6tlsd
-
-#else
-#ifdef S6_NETWORKING_USE_BEARSSL
-
-#include <s6-networking/sbearssl.h>
-#define s6tlsd sbearssl_s6tlsd
-
-#else
-
-#error No SSL backend configured.
-
-#endif
-#endif
 
+#include "s6tls-internal.h"
 
 #define USAGE "s6-tlsd [ -S | -s ] [ -Y | -y ] [ -v verbosity ] [ -K timeout ] [ -Z | -z ] prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
-int main (int argc, char const *const *argv, char const *const *envp)
+static void child (int const [3][2], uint32_t, unsigned int, unsigned int) gccattr_noreturn ;
+static void child (int const p[3][2], uint32_t options, unsigned int verbosity, unsigned int kimeout)
+{
+  int fds[3] = { p[0][0], p[1][1], p[2][1] } ;
+  PROG = "s6-tlsd (child)" ;
+  close(p[2][0]) ;
+  close(p[0][1]) ;
+  close(p[1][0]) ;
+  s6tls_drop() ;
+  s6tls_exec_tlsdio(fds, options, verbosity, kimeout) ;
+}
+
+int main (int argc, char const *const *argv)
 {
-  tain_t tto ;
   unsigned int verbosity = 1 ;
-  uid_t uid = 0 ;
-  gid_t gid = 0 ;
-  uint32_t preoptions = 2 ;
-  uint32_t options = 1 ;
+  unsigned int kimeout = 0 ;
+  int p[3][2] ;
+  uint32_t options = 0 ;
+  int cleanenv = 1 ;
+  pid_t pid ;
 
-  PROG = "s6-tlsd" ;
+  PROG = "s6-tlsd (parent)" ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
-    unsigned int t = 0 ;
     for (;;)
     {
       int opt = subgetopt_r(argc, argv, "SsYyv:K:Zz", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
-        case 'S' : options &= ~(uint32_t)1 ; break ;
-        case 's' : options |= 1 ; break ;
-        case 'Y' : preoptions |= 1 ; preoptions &= ~(uint32_t)4 ; break ;
-        case 'y' : preoptions |= 5 ; break ;
+        case 'S' : options |= 4 ; break ;
+        case 's' : options &= ~4 ; break ;
+        case 'Y' : options |= 1 ; options &= ~2 ; break ;
+        case 'y' : options |= 3 ; break ;
         case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
-        case 'K' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
-        case 'Z' : preoptions &= ~(uint32_t)2 ; break ;
-        case 'z' : preoptions |= 2 ; break ;
+        case 'K' : if (!uint0_scan(l.arg, &kimeout)) dieusage() ; break ;
+        case 'Z' : cleanenv = 0 ; break ;
+        case 'z' : cleanenv = 1 ; break ;
         default : dieusage() ;
       }
     }
     argc -= l.ind ; argv += l.ind ;
-    if (t) tain_from_millisecs(&tto, t) ; else tto = tain_infinite_relative ;
   }
   if (!argc) dieusage() ;
 
-  if (!getuid())
+  if (pipe(p[0]) < 0 || pipe(p[1]) < 0 || pipe(p[2]) < 0)
+    strerr_diefu1sys(111, "pipe") ;
+  pid = fork() ;
+  switch (pid)
   {
-    char const *x = env_get2(envp, "TLS_UID") ;
-    if (x && !uid0_scan(x, &uid)) strerr_dieinvalid(100, "TLS_UID") ;
-    x = env_get2(envp, "TLS_GID") ;
-    if (x && !gid0_scan(x, &gid)) strerr_dieinvalid(100, "TLS_GID") ;
+    case -1 : strerr_diefu1sys(111, "fork") ;
+    case 0 : child(p, options, verbosity, kimeout) ;
+    default : break ;
   }
 
-  tain_now_set_stopwatch_g() ;
-  return s6tlsd(argv, envp, &tto, preoptions, options, uid, gid, verbosity) ;
+  s6tls_wait_and_exec_app(argv, p, pid, 0, 1, cleanenv ? 1 : 0) ;
 }
diff --git a/src/conn-tools/s6-ucspitlsd.c b/src/conn-tools/s6-ucspitlsd.c
new file mode 100644
index 0000000..ae2ca41
--- /dev/null
+++ b/src/conn-tools/s6-ucspitlsd.c
@@ -0,0 +1,114 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include <skalibs/gccattributes.h>
+#include <skalibs/types.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/env.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/webipc.h>
+
+#include <s6-networking/config.h>
+#include "s6tls-internal.h"
+
+#define USAGE "s6-ucspitlsd [ -S | -s ] [ -Y | -y ] [ -v verbosity ] [ -K timeout ] [ -Z | -z ] prog..."
+#define dieusage() strerr_dieusage(100, USAGE)
+
+static inline void child (int [3][2], uint32_t, unsigned int, unsigned int) gccattr_noreturn ;
+static inline void child (int p[3][2], uint32_t options, unsigned int verbosity, unsigned int kimeout)
+{
+  int fds[3] = { p[0][0], p[1][1], p[2][1] } ;
+  ssize_t r ;
+  char c ;
+  PROG = "s6-ucspitlsd" ;
+  close(p[2][0]) ;
+  close(p[0][1]) ;
+  close(p[1][0]) ;
+  s6tls_drop() ;
+  r = read(p[2][1], &c, 1) ;
+  if (r < 0) strerr_diefu1sys(111, "read from control socket") ;
+  if (!r) _exit(0) ;
+  switch (c)
+  {
+    case 'y' :
+      close(p[2][1]) ;
+      p[2][1] = 0 ; /* we know 0 is open so it's a correct invalid value */
+    case 'Y' :
+      fd_shutdown(p[2][1], 0) ;
+      break ;
+    default :
+      strerr_dief1x(100, "unrecognized command on control socket") ;
+  }
+  s6tls_exec_tlsdio(fds, options, verbosity, kimeout) ;
+}
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  unsigned int kimeout = 0 ;
+  unsigned int verbosity = 1 ;
+  uint32_t options = 0 ;
+  int cleanenv = 1 ;
+  int p[3][2] ;
+
+  PROG = "s6-ucspitlsd (parent)" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "SsYyv:K:Zz", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'S' : options |= 4 ; break ;
+        case 's' : options &= ~4 ; break ;
+        case 'Y' : options |= 1 ; options &= ~2 ; break ;
+        case 'y' : options |= 3 ; break ;
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 'K' : if (!uint0_scan(l.arg, &kimeout)) dieusage() ; break ;
+        case 'Z' : cleanenv = 0 ; break ;
+        case 'z' : cleanenv = 1 ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) dieusage() ;
+
+  if (ipc_pair_b(p[2]) < 0) strerr_diefu1sys(111, "ipc_pair") ;
+  if (pipe(p[0]) < 0 || pipe(p[1]) < 0) strerr_diefu1sys(111, "pipe") ;
+
+  switch (fork())
+  {
+    case -1 : strerr_diefu1sys(111, "fork") ;
+    case 0 : child(p, options, verbosity, kimeout) ;
+    default : break ;
+  }
+
+  {
+    size_t m = 0 ;
+    char modif[sizeof(s6tls_envvars) + 33 + 3 * UINT_FMT] ;
+    close(p[2][1]) ;
+    close(p[1][1]) ;
+    close(p[0][0]) ;
+    if (cleanenv)
+    {
+      memcpy(modif + m, s6tls_envvars, sizeof(s6tls_envvars)) ;
+      m += sizeof(s6tls_envvars) ;
+    }
+    memcpy(modif + m, "SSLCTLFD=", 9) ; m += 9 ;
+    m += uint_fmt(modif + m, p[2][0]) ;
+    modif[m++] = 0 ;
+    memcpy(modif + m, "SSLREADFD=", 10) ; m += 10 ;
+    m += uint_fmt(modif + m, p[1][0]) ;
+    modif[m++] = 0 ;
+    memcpy(modif + m, "SSLWRITEFD=", 11) ; m += 11 ;
+    m += uint_fmt(modif + m, p[0][1]) ;
+    modif[m++] = 0 ;
+    xpathexec_r(argv, envp, env_len(envp), modif, m) ;
+  }
+}
diff --git a/src/conn-tools/s6tls-internal.h b/src/conn-tools/s6tls-internal.h
new file mode 100644
index 0000000..48df60f
--- /dev/null
+++ b/src/conn-tools/s6tls-internal.h
@@ -0,0 +1,18 @@
+/* ISC license */
+
+#ifndef S6TLS_INTERNAL_H
+#define S6TLS_INTERNAL_H
+
+#include <stdint.h>
+#include <unistd.h>
+
+#include <skalibs/gccattributes.h>
+
+#define s6tls_envvars "CADIR\0CAFILE\0KEYFILE\0CERTFILE\0TLS_UID\0TLS_GID"
+
+extern void s6tls_drop (void) ;
+extern void s6tls_exec_tlscio (int const *, uint32_t, unsigned int, unsigned int, char const *) gccattr_noreturn ;
+extern void s6tls_exec_tlsdio (int const *, uint32_t, unsigned int, unsigned int) gccattr_noreturn ;
+extern void s6tls_wait_and_exec_app (char const *const *, int const [3][2], pid_t, int, int, uint32_t) gccattr_noreturn ;
+
+#endif
diff --git a/src/conn-tools/s6tls_drop.c b/src/conn-tools/s6tls_drop.c
new file mode 100644
index 0000000..6b6f67f
--- /dev/null
+++ b/src/conn-tools/s6tls_drop.c
@@ -0,0 +1,24 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <stdlib.h>
+
+#include <skalibs/strerr2.h>
+#include <skalibs/types.h>
+
+#include "s6tls-internal.h"
+
+void s6tls_drop (void)
+{
+  if (!getuid())
+  {
+    uid_t uid ;
+    gid_t gid ;
+    char const *x = getenv("TLS_UID") ;
+    if (x && !uid0_scan(x, &uid)) strerr_dieinvalid(100, "TLS_UID") ;
+    x = getenv("TLS_GID") ;
+    if (x && !gid0_scan(x, &gid)) strerr_dieinvalid(100, "TLS_GID") ;
+    if (gid && setgid(gid) < 0) strerr_diefu1sys(111, "setgid") ;
+    if (uid && setuid(uid) < 0) strerr_diefu1sys(111, "setuid") ;
+  }
+}
diff --git a/src/conn-tools/s6tls_exec_tlscio.c b/src/conn-tools/s6tls_exec_tlscio.c
new file mode 100644
index 0000000..ad00ecd
--- /dev/null
+++ b/src/conn-tools/s6tls_exec_tlscio.c
@@ -0,0 +1,53 @@
+/* ISC license. */
+
+#include <skalibs/posixplz.h>
+#include <skalibs/types.h>
+#include <skalibs/djbunix.h>
+
+#include <s6-networking/config.h>
+#include "s6tls-internal.h"
+
+void s6tls_exec_tlscio (int const *fds, uint32_t options, unsigned int verbosity, unsigned int kimeout, char const *servername)
+{
+  char const *newargv[15] ;
+  unsigned int m = 0 ;
+  char fmtv[UINT_FMT] ;
+  char fmtd[UINT_FMT] ;
+  char fmtk[UINT_FMT] ;
+  char fmtr[UINT_FMT] ;
+  char fmtw[UINT_FMT] ;
+
+  newargv[m++] = S6_NETWORKING_BINPREFIX "s6-tlsc-io" ;
+  if (verbosity != 1)
+  {
+    newargv[m++] = "-v" ;
+    newargv[m++] = fmtv ;
+    fmtv[uint_fmt(fmtv, verbosity)] = 0 ;
+  }
+  if (fds[2])
+  {
+    newargv[m++] = "-d" ;
+    newargv[m++] = fmtd ;
+    fmtd[uint_fmt(fmtd, fds[2])] = 0 ;
+  }
+  newargv[m++] = options & 4 ? "-S" : "-s" ;
+  newargv[m++] = options & 1 ? "-y" : "-Y" ;
+  if (kimeout)
+  {
+    newargv[m++] = "-K" ;
+    newargv[m++] = fmtk ;
+    fmtk[uint_fmt(fmtk, kimeout)] = 0 ;
+  }
+  if (servername)
+  {
+    newargv[m++] = "-k" ;
+    newargv[m++] = servername ;
+  }
+  newargv[m++] = "--" ;
+  newargv[m++] = fmtr ;
+  fmtr[uint_fmt(fmtr, fds[0])] = 0 ;
+  newargv[m++] = fmtw ;
+  fmtw[uint_fmt(fmtw, fds[1])] = 0 ;
+  newargv[m++] = 0 ;
+  xpathexec_run(newargv[0], newargv, (char const *const *)environ) ;
+}
diff --git a/src/conn-tools/s6tls_exec_tlsdio.c b/src/conn-tools/s6tls_exec_tlsdio.c
new file mode 100644
index 0000000..b00adb2
--- /dev/null
+++ b/src/conn-tools/s6tls_exec_tlsdio.c
@@ -0,0 +1,49 @@
+/* ISC license. */
+
+#include <skalibs/posixplz.h>
+#include <skalibs/types.h>
+#include <skalibs/djbunix.h>
+
+#include <s6-networking/config.h>
+#include "s6tls-internal.h"
+
+void s6tls_exec_tlsdio (int const *fds, uint32_t options, unsigned int verbosity, unsigned int kimeout)
+{
+  char const *newargv[13] ;
+  unsigned int m = 0 ;
+  char fmtv[UINT_FMT] ;
+  char fmtd[UINT_FMT] ;
+  char fmtk[UINT_FMT] ;
+  char fmtr[UINT_FMT] ;
+  char fmtw[UINT_FMT] ;
+
+  newargv[m++] = S6_NETWORKING_BINPREFIX "s6-tlsd-io" ;
+  if (verbosity != 1)
+  {
+    newargv[m++] = "-v" ;
+    newargv[m++] = fmtv ;
+    fmtv[uint_fmt(fmtv, verbosity)] = 0 ;
+  }
+  if (fds[2])
+  {
+    newargv[m++] = "-d" ;
+    newargv[m++] = fmtd ;
+    fmtd[uint_fmt(fmtd, fds[2])] = 0 ;
+  }
+  newargv[m++] = options & 4 ? "-S" : "-s" ;
+  if (options & 1)
+    newargv[m++] = options & 2 ? "-y" : "-Y" ;
+  if (kimeout)
+  {
+    newargv[m++] = "-K" ;
+    newargv[m++] = fmtk ;
+    fmtk[uint_fmt(fmtk, kimeout)] = 0 ;
+  }
+  newargv[m++] = "--" ;
+  newargv[m++] = fmtr ;
+  fmtr[uint_fmt(fmtr, fds[0])] = 0 ;
+  newargv[m++] = fmtw ;
+  fmtw[uint_fmt(fmtw, fds[1])] = 0 ;
+  newargv[m++] = 0 ;
+  xpathexec_run(newargv[0], newargv, (char const *const *)environ) ;
+}
diff --git a/src/conn-tools/s6tls_wait_and_exec_app.c b/src/conn-tools/s6tls_wait_and_exec_app.c
new file mode 100644
index 0000000..20828f6
--- /dev/null
+++ b/src/conn-tools/s6tls_wait_and_exec_app.c
@@ -0,0 +1,43 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <unistd.h>
+
+#include <skalibs/posixplz.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/env.h>
+#include <skalibs/djbunix.h>
+
+#include "s6tls-internal.h"
+
+#define MAXENVSIZE 2048
+
+void s6tls_wait_and_exec_app (char const *const *argv, int const p[3][2], pid_t pid, int fdr, int fdw, uint32_t options)
+{
+  char buf[sizeof(s6tls_envvars) + MAXENVSIZE] ;
+  size_t m = 0 ;
+  ssize_t r ;
+  close(p[2][1]) ;
+  close(p[1][1]) ;
+  close(p[0][0]) ;
+  if (fd_move(fdr, p[1][0]) < 0 || fd_move(fdw, p[0][1]) < 0)
+    strerr_diefu1sys(111, "move file descriptors") ;
+  if (options & 1)
+  {
+    memcpy(buf + m, s6tls_envvars, sizeof(s6tls_envvars)) ;
+    m += sizeof(s6tls_envvars) ;
+  }
+  r = read(p[2][0], buf + m, MAXENVSIZE) ;
+  if (r < 0) strerr_diefu1sys(111, "read from handshake notification pipe") ;
+  if (!r)
+  {
+    int wstat ;
+    if (wait_pid(pid, &wstat) < 0)
+      strerr_diefu1sys(111, "wait") ;
+    _exit(wait_estatus(wstat)) ;
+  }
+  if (r >= MAXENVSIZE)
+    strerr_dief1x(100, "SSL data too large") ;
+  m += r - 1 ;
+  xpathexec_r(argv, (char const *const *)environ, env_len((char const *const *)environ), buf, m) ;
+}