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.

1 files changed, 126 insertions, 0 deletions

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) ;
+}