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.

6 files changed, 59 insertions, 152 deletions

diff --git a/src/sbearssl/deps-lib/sbearssl b/src/sbearssl/deps-lib/sbearssl
index c0acfb6..55729f6 100644
--- a/src/sbearssl/deps-lib/sbearssl
+++ b/src/sbearssl/deps-lib/sbearssl
@@ -1,5 +1,4 @@
 sbearssl_append.o
-sbearssl_prep_spawn_drop.o
 sbearssl_cert_from.o
 sbearssl_cert_readbigpem.o
 sbearssl_cert_readfile.o
@@ -33,7 +32,7 @@ sbearssl_ta_to.o
 sbearssl_x500_name_len.o
 sbearssl_x500_from_ta.o
 sbearssl_x509_minimal_set_tai.o
-sbearssl_s6tlsc.o
-sbearssl_s6tlsd.o
+sbearssl_client_init_and_run.o
+sbearssl_server_init_and_run.o
 -lbearssl
 -lskarnet
diff --git a/src/sbearssl/sbearssl-internal.h b/src/sbearssl/sbearssl-internal.h
index cbf355b..25f6468 100644
--- a/src/sbearssl/sbearssl-internal.h
+++ b/src/sbearssl/sbearssl-internal.h
@@ -19,6 +19,5 @@ struct sbearssl_strallocerr_s
 
 extern void sbearssl_append (void *, void const *, size_t) ;
 extern int sbearssl_pem_push (br_pem_decoder_context *, char const *, size_t, sbearssl_pemobject *, genalloc *, sbearssl_strallocerr *, int *) ;
-extern pid_t sbearssl_prep_spawn_drop (char const *const *, char const *const *, int *, uid_t, gid_t, uint32_t) ;
 
 #endif
diff --git a/src/sbearssl/sbearssl_s6tlsc.c b/src/sbearssl/sbearssl_client_init_and_run.c
index 267d79c..a95e9e1 100644
--- a/src/sbearssl/sbearssl_s6tlsc.c
+++ b/src/sbearssl/sbearssl_client_init_and_run.c
@@ -1,36 +1,35 @@
 /* ISC license. */
 
-#include <unistd.h>
-#include <errno.h>
+#include <stddef.h>
+#include <stdlib.h>
+
 #include <bearssl.h>
+
 #include <skalibs/strerr2.h>
-#include <skalibs/env.h>
 #include <skalibs/stralloc.h>
 #include <skalibs/genalloc.h>
-#include <skalibs/djbunix.h>
 #include <skalibs/random.h>
+
 #include <s6-networking/sbearssl.h>
 #include "sbearssl-internal.h"
 
-int sbearssl_s6tlsc (char const *const *argv, char const *const *envp, tain_t const *tto, uint32_t preoptions, uint32_t options, uid_t uid, gid_t gid, unsigned int verbosity, char const *servername, int *sfd)
+void sbearssl_client_init_and_run (int *fds, tain_t const *tto, uint32_t preoptions, uint32_t options, unsigned int verbosity, char const *servername, sbearssl_handshake_cb_t_ref cb, unsigned int notif)
 {
-  int fds[5] = { sfd[0], sfd[1], sfd[0], sfd[1] } ;
   stralloc storage = STRALLOC_ZERO ;
   genalloc tas = GENALLOC_ZERO ;
   size_t talen ;
-  pid_t pid ;
 
   if (preoptions & 1)
     strerr_dief1x(100, "client certificates are not supported yet") ;
 
   {
     int r ;
-    char const *x = env_get2(envp, "CADIR") ;
+    char const *x = getenv("CADIR") ;
     if (x)
       r = sbearssl_ta_readdir(x, &tas, &storage) ;
     else
     {
-      x = env_get2(envp, "CAFILE") ;
+      x = getenv("CAFILE") ;
       if (!x) strerr_dienotset(100, "CADIR or CAFILE") ;
       r = sbearssl_ta_readfile(x, &tas, &storage) ;
     }
@@ -45,17 +44,13 @@ int sbearssl_s6tlsc (char const *const *argv, char const *const *envp, tain_t co
       strerr_dief2x(96, "no trust anchor found in ", x) ;
   }
 
-  if (!random_init()) strerr_diefu1sys(111, "initialize random generator") ;
-
-  pid = sbearssl_prep_spawn_drop(argv, envp, fds, uid, gid, !!(preoptions & 2)) ;
-
   {
+    sbearssl_handshake_cb_context_t cbarg = { .notif = notif } ;
     unsigned char buf[BR_SSL_BUFSIZE_BIDI] ;
     br_x509_minimal_context xc ;
     br_ssl_client_context cc ;
     br_x509_trust_anchor btas[talen] ;
     size_t i = talen ;
-    int wstat ;
 
     stralloc_shrink(&storage) ;
     while (i--)
@@ -63,17 +58,14 @@ int sbearssl_s6tlsc (char const *const *argv, char const *const *envp, tain_t co
     genalloc_free(sbearssl_ta, &tas) ;
     br_ssl_client_init_full(&cc, &xc, btas, talen) ;
     random_string((char *)buf, 32) ;
-    br_ssl_engine_inject_entropy(&cc.eng, buf, 32) ;
     random_finish() ;
+    br_ssl_engine_inject_entropy(&cc.eng, buf, 32) ;
     br_ssl_engine_set_buffer(&cc.eng, buf, sizeof(buf), 1) ;
     if (!br_ssl_client_reset(&cc, servername, 0))
       strerr_diefu2x(97, "reset client context: ", sbearssl_error_str(br_ssl_engine_last_error(&cc.eng))) ;
-    tain_now_g() ;
     if (!sbearssl_x509_minimal_set_tain(&xc, &STAMP))
       strerr_diefu1sys(111, "initialize validation time") ;
 
-    wstat = sbearssl_run(&cc.eng, fds, pid, verbosity, options, tto) ;
-    if (wstat < 0 && wait_pid(pid, &wstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
-    return wait_estatus(wstat) ;
+    sbearssl_run(&cc.eng, fds, tto, options, verbosity, cb, &cbarg) ;
   }
 }
diff --git a/src/sbearssl/sbearssl_prep_spawn_drop.c b/src/sbearssl/sbearssl_prep_spawn_drop.c
deleted file mode 100644
index 1ca7eb8..0000000
--- a/src/sbearssl/sbearssl_prep_spawn_drop.c
+++ /dev/null
@@ -1,35 +0,0 @@
-/* ISC license. */
-
-#include <unistd.h>
-#include <signal.h>
-#include <skalibs/env.h>
-#include <skalibs/strerr2.h>
-#include <skalibs/djbunix.h>
-#include <skalibs/selfpipe.h>
-#include "sbearssl-internal.h"
-
-pid_t sbearssl_prep_spawn_drop (char const *const *argv, char const *const *envp, int *fds, uid_t uid, gid_t gid, uint32_t options)
-{
-  pid_t pid ;
-
-  fds[4] = selfpipe_init() ;
-  if (fds[4] < 0) strerr_diefu1sys(111, "init selfpipe") ;
-  if (selfpipe_trap(SIGCHLD) < 0) strerr_diefu1sys(111, "trap SIGCHLD") ;
-
-  if (!(options & 1)) pid = child_spawn2(argv[0], argv, envp, fds) ;
-  else
-  {
-    char const modifs[] = "CADIR\0CAFILE\0KEYFILE\0CERTFILE\0TLS_UID\0TLS_GID" ;
-    size_t modiflen = sizeof(modifs) ;
-    size_t n = env_len(envp) ;
-    char const *newenv[n + 7] ;
-    size_t newenvlen = env_merge(newenv, n+7, envp, n, modifs, modiflen) ;
-    if (!newenvlen) return 0 ;
-    pid = child_spawn2(argv[0], argv, newenv, fds) ;
-  }
-
-  if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
-  if (gid && setgid(gid) < 0) strerr_diefu1sys(111, "setgid") ;
-  if (uid && setuid(uid) < 0) strerr_diefu1sys(111, "setuid") ;
-  return pid ;
-}
diff --git a/src/sbearssl/sbearssl_run.c b/src/sbearssl/sbearssl_run.c
index 177a252..c8ff2fe 100644
--- a/src/sbearssl/sbearssl_run.c
+++ b/src/sbearssl/sbearssl_run.c
@@ -1,53 +1,30 @@
 /* ISC license. */
 
-#include <skalibs/nonposix.h>
-#include <sys/socket.h>
+#include <unistd.h>
 #include <errno.h>
-#include <signal.h>
+
 #include <bearssl.h>
+
 #include <skalibs/error.h>
 #include <skalibs/strerr2.h>
-#include <skalibs/sig.h>
 #include <skalibs/tai.h>
 #include <skalibs/iopause.h>
 #include <skalibs/djbunix.h>
-#include <skalibs/selfpipe.h>
-#include <s6-networking/sbearssl.h>
 
-static inline void handle_signals (pid_t pid, int *e)
-{
-  for (;;) switch (selfpipe_read())
-  {
-    case -1 : strerr_diefu1sys(111, "read selfpipe") ;
-    case 0 : return ;
-    case SIGCHLD :
-    {
-      int wstat ;
-      if (wait_pid_nohang(pid, &wstat) == pid)
-      {
-        *e = wstat ;
-        return ;
-      }
-    }
-  }
-}
+#include <s6-networking/sbearssl.h>
+#include "sbearssl-internal.h"
 
-int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int verbosity, uint32_t options, tain_t const *tto)
+void sbearssl_run (br_ssl_engine_context *ctx, int *fds, tain_t const *tto, uint32_t options, unsigned int verbosity, sbearssl_handshake_cb_t_ref cb, sbearssl_handshake_cb_context_t *cbarg)
 {
-  iopause_fd x[5] = { { .fd = fds[4], .events = IOPAUSE_READ } } ;
+  iopause_fd x[4] ;
   unsigned int xindex[4] ;
   int markedforflush = 0 ;
-  int e = -1 ;
-
-  if (ndelay_on(fds[2]) < 0 || ndelay_on(fds[3]) < 0)
-    strerr_diefu1sys(111, "set fds non-blocking") ;
-  if (sig_ignore(SIGPIPE) < 0)
-    strerr_diefu1sys(111, "ignore SIGPIPE") ;
+  int handshake_done = 0 ;
 
   for (;;)
   {
     tain_t deadline ;
-    unsigned int j = 1 ;
+    unsigned int j = 0 ;
     unsigned int state = br_ssl_engine_current_state(ctx) ;
     int r ;
 
@@ -58,6 +35,17 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
       break ;
     }
 
+    if (!handshake_done)
+    {
+      size_t dummy ;
+      if (br_ssl_engine_recvapp_buf(ctx, &dummy))
+      {
+        if (!(*cb)(ctx, cbarg))
+          strerr_diefu1sys(111, "post-handshake callback failed") ;
+        handshake_done = 1 ;
+      }
+    }
+
     tain_add_g(&deadline, fds[0] >= 0 && fds[2] >= 0 && state & (BR_SSL_SENDAPP | BR_SSL_RECVREC) ? tto : &tain_infinite_relative) ;
 
     if (fds[0] >= 0 && state & BR_SSL_SENDAPP)
@@ -66,62 +54,42 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
       x[j].events = IOPAUSE_READ ;
       xindex[0] = j++ ;
     }
-    else xindex[0] = 5 ;
+    else xindex[0] = 4 ;
     if (fds[1] >= 0 && state & BR_SSL_RECVAPP)
     {
       x[j].fd = fds[1] ;
       x[j].events = IOPAUSE_WRITE ;
       xindex[1] = j++ ;
     }
-    else xindex[1] = 5 ;
+    else xindex[1] = 4 ;
     if (fds[2] >= 0 && state & BR_SSL_RECVREC)
     {
       x[j].fd = fds[2] ;
       x[j].events = IOPAUSE_READ ;
       xindex[2] = j++ ;
     }
-    else xindex[2] = 5 ;
+    else xindex[2] = 4 ;
     if (fds[3] >= 0 && state & BR_SSL_SENDREC)
     {
       x[j].fd = fds[3] ;
       x[j].events = IOPAUSE_WRITE ;
       xindex[3] = j++ ;
     }
-    else xindex[3] = 5 ;
+    else xindex[3] = 4 ;
 
-    if (j == 1) break ;
+    if (xindex[0] == 4 && xindex[1] == 4 && xindex[3] == 4) break ;
     r = iopause_g(x, j, &deadline) ;
     if (r < 0) strerr_diefu1sys(111, "iopause") ;
-    else if (!r)
-    {
-      fd_close(fds[0]) ; fds[0] = -1 ;
-      if (options & 1)
-      {
-        shutdown(fds[3], SHUT_WR) ;
-        fd_close(fds[3]) ; fds[3] = -1 ;
-      }
-      else br_ssl_engine_close(ctx) ;
-      if (e >= 0) break ;
-      continue ;
-    }
+    else if (!r) break ;
 
     while (j--)
       if (x[j].revents & IOPAUSE_EXCEPT)
         x[j].revents |= IOPAUSE_READ | IOPAUSE_WRITE ;
 
 
-   /* Signal */
-
-    if (x[0].revents & IOPAUSE_READ)
-    {
-      handle_signals(pid, &e) ;
-      if (e >= 0 && xindex[0] == 5 && xindex[3] == 5) break ;
-    }
-
-
    /* Flush to local */
 
-    if (state & BR_SSL_RECVAPP && x[xindex[1]].events & x[xindex[1]].revents & IOPAUSE_WRITE)
+    if (state & BR_SSL_RECVAPP && xindex[1] < 4 && x[xindex[1]].events & x[xindex[1]].revents & IOPAUSE_WRITE)
     {
       size_t len ;
       unsigned char const *s = br_ssl_engine_recvapp_buf(ctx, &len) ;
@@ -145,7 +113,7 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
 
    /* Flush to remote */
 
-    if (state & BR_SSL_SENDREC && xindex[3] < 5 && x[xindex[3]].events & x[xindex[3]].revents & IOPAUSE_WRITE)
+    if (state & BR_SSL_SENDREC && xindex[3] < 4 && x[xindex[3]].events & x[xindex[3]].revents & IOPAUSE_WRITE)
     {
       size_t len ;
       unsigned char const *s = br_ssl_engine_sendrec_buf(ctx, &len) ;
@@ -162,11 +130,10 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
         {
           if (options & 1)
           {
-            shutdown(fds[3], SHUT_WR) ;
+            fd_shutdown(fds[3], 1) ;
             fd_close(fds[3]) ; fds[3] = -1 ;
           }
           else br_ssl_engine_close(ctx) ;
-          if (e >= 0) break ;
         }
         state = br_ssl_engine_current_state(ctx) ;
       }
@@ -175,7 +142,7 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
 
    /* Fill from local */
 
-    if (state & BR_SSL_SENDAPP && xindex[0] < 5 && x[xindex[0]].events & IOPAUSE_READ && (markedforflush || x[xindex[0]].revents & IOPAUSE_READ))
+    if (state & BR_SSL_SENDAPP && xindex[0] < 4 && x[xindex[0]].events & IOPAUSE_READ && (markedforflush || x[xindex[0]].revents & IOPAUSE_READ))
     {
       size_t len ;
       unsigned char *s = br_ssl_engine_sendapp_buf(ctx, &len) ;
@@ -191,11 +158,10 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
           {
             if (options & 1)
             {
-              shutdown(fds[3], SHUT_WR) ;
+              fd_shutdown(fds[3], 1) ;
               fd_close(fds[3]) ; fds[3] = -1 ;
             }
             else br_ssl_engine_close(ctx) ;
-            if (e >= 0) break ;
           }
         }
       }
@@ -215,7 +181,7 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
 
    /* Fill from remote */
 
-    if (state & BR_SSL_RECVREC && xindex[2] < 5 && x[xindex[2]].events & x[xindex[2]].revents & IOPAUSE_READ)
+    if (state & BR_SSL_RECVREC && xindex[2] < 4 && x[xindex[2]].events & x[xindex[2]].revents & IOPAUSE_READ)
     {
       size_t len ;
       unsigned char *s = br_ssl_engine_recvrec_buf(ctx, &len) ;
@@ -224,7 +190,7 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
       {
         if (!error_isagain(errno))
         {
-          if (options & 1) shutdown(fds[2], SHUT_RD) ;
+          if (options & 1) fd_shutdown(fds[2], 0) ;
           fd_close(fds[2]) ; fds[2] = -1 ;
           if (fds[1] >= 0 && !br_ssl_engine_recvapp_buf(ctx, &len))
           {
@@ -235,10 +201,5 @@ int sbearssl_run (br_ssl_engine_context *ctx, int *fds, pid_t pid, unsigned int
       else br_ssl_engine_recvrec_ack(ctx, w) ;
     }
   }
-
-  if (fds[1] >= 0) fd_close(fds[1]) ;
-  if (fds[0] >= 0) fd_close(fds[0]) ;
-  if (fds[3] >= 0) fd_close(fds[3]) ;
-  if (fds[2] >= 0) fd_close(fds[2]) ;
-  return e ;
+  _exit(0) ;
 }
diff --git a/src/sbearssl/sbearssl_s6tlsd.c b/src/sbearssl/sbearssl_server_init_and_run.c
index 6c3d163..778fdbd 100644
--- a/src/sbearssl/sbearssl_s6tlsd.c
+++ b/src/sbearssl/sbearssl_server_init_and_run.c
@@ -1,31 +1,30 @@
 /* ISC license. */
 
-#include <unistd.h>
-#include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+
 #include <bearssl.h>
+
 #include <skalibs/strerr2.h>
-#include <skalibs/env.h>
 #include <skalibs/stralloc.h>
 #include <skalibs/genalloc.h>
-#include <skalibs/djbunix.h>
 #include <skalibs/random.h>
+
 #include <s6-networking/sbearssl.h>
 #include "sbearssl-internal.h"
 
-int sbearssl_s6tlsd (char const *const *argv, char const *const *envp, tain_t const *tto, uint32_t preoptions, uint32_t options, uid_t uid, gid_t gid, unsigned int verbosity)
+void sbearssl_server_init_and_run (int *fds, tain_t const *tto, uint32_t preoptions, uint32_t options, unsigned int verbosity, sbearssl_handshake_cb_t_ref cb, unsigned int notif)
 {
-  int fds[5] = { 0, 1, 0, 1 } ;
   stralloc storage = STRALLOC_ZERO ;
   sbearssl_skey skey ;
   genalloc certs = GENALLOC_ZERO ;
   size_t chainlen ;
-  pid_t pid ;
 
   if (preoptions & 1)
     strerr_dief1x(100, "client certificates are not supported yet") ;
 
   {
-    char const *x = env_get2(envp, "KEYFILE") ;
+    char const *x = getenv("KEYFILE") ;
     int r ;
     if (!x) strerr_dienotset(100, "KEYFILE") ;
     r = sbearssl_skey_readfile(x, &skey, &storage) ;
@@ -34,7 +33,7 @@ int sbearssl_s6tlsd (char const *const *argv, char const *const *envp, tain_t co
     else if (r)
       strerr_diefu4x(96, "decode private key in ", x, ": ", sbearssl_error_str(r)) ;
 
-    x = env_get2(envp, "CERTFILE") ;
+    x = getenv("CERTFILE") ;
     if (!x) strerr_dienotset(100, "CERTFILE") ;
     r = sbearssl_cert_readbigpem(x, &certs, &storage) ;
     if (r < 0)
@@ -46,17 +45,13 @@ int sbearssl_s6tlsd (char const *const *argv, char const *const *envp, tain_t co
       strerr_diefu2x(96, "find a certificate in ", x) ;
   }
 
-  if (!random_init()) strerr_diefu1sys(111, "initialize random generator") ;
-
-  pid = sbearssl_prep_spawn_drop(argv, envp, fds, uid, gid, !!(preoptions & 2)) ;
-
   {
+    sbearssl_handshake_cb_context_t cbarg = { .notif = notif } ;
     unsigned char buf[BR_SSL_BUFSIZE_BIDI] ;
     br_ssl_server_context sc ;
     union br_skey_u key ;
     br_x509_certificate chain[chainlen] ;
     size_t i = chainlen ;
-    int wstat ;
 
     stralloc_shrink(&storage) ;
     while (i--)
@@ -93,20 +88,16 @@ int sbearssl_s6tlsd (char const *const *argv, char const *const *envp, tain_t co
       if (preoptions & 1)
       {
         /* br_ssl_server_set_trust_anchor_names(&sc, x500names, x500n) ; */
-        if (!(preoptions & 4)) flags |= BR_OPT_TOLERATE_NO_CLIENT_AUTH ;
+        if (!(preoptions & 2)) flags |= BR_OPT_TOLERATE_NO_CLIENT_AUTH ;
       }
       br_ssl_engine_add_flags(&sc.eng, flags) ;
     }
 
     random_string((char *)buf, 32) ;
-    br_ssl_engine_inject_entropy(&sc.eng, buf, 32) ;
     random_finish() ;
+    br_ssl_engine_inject_entropy(&sc.eng, buf, 32) ;
     br_ssl_engine_set_buffer(&sc.eng, buf, sizeof(buf), 1) ;
     br_ssl_server_reset(&sc) ;
-    tain_now_g() ;
-
-    wstat = sbearssl_run(&sc.eng, fds, pid, verbosity, options, tto) ;
-    if (wstat < 0 && wait_pid(pid, &wstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
-    return wait_estatus(wstat) ;
+    sbearssl_run(&sc.eng, fds, tto, options, verbosity, cb, &cbarg) ;
   }
 }