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, 71 insertions, 0 deletions

diff --git a/src/sbearssl/sbearssl_client_init_and_run.c b/src/sbearssl/sbearssl_client_init_and_run.c
new file mode 100644
index 0000000..a95e9e1
--- /dev/null
+++ b/src/sbearssl/sbearssl_client_init_and_run.c
@@ -0,0 +1,71 @@
+/* ISC license. */
+
+#include <stddef.h>
+#include <stdlib.h>
+
+#include <bearssl.h>
+
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/genalloc.h>
+#include <skalibs/random.h>
+
+#include <s6-networking/sbearssl.h>
+#include "sbearssl-internal.h"
+
+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)
+{
+  stralloc storage = STRALLOC_ZERO ;
+  genalloc tas = GENALLOC_ZERO ;
+  size_t talen ;
+
+  if (preoptions & 1)
+    strerr_dief1x(100, "client certificates are not supported yet") ;
+
+  {
+    int r ;
+    char const *x = getenv("CADIR") ;
+    if (x)
+      r = sbearssl_ta_readdir(x, &tas, &storage) ;
+    else
+    {
+      x = getenv("CAFILE") ;
+      if (!x) strerr_dienotset(100, "CADIR or CAFILE") ;
+      r = sbearssl_ta_readfile(x, &tas, &storage) ;
+    }
+
+    if (r < 0)
+      strerr_diefu2sys(111, "read trust anchors in ", x) ;
+    else if (r)
+      strerr_diefu4x(96, "read trust anchors in ", x, ": ", sbearssl_error_str(r)) ;
+
+    talen = genalloc_len(sbearssl_ta, &tas) ;
+    if (!talen)
+      strerr_dief2x(96, "no trust anchor found in ", x) ;
+  }
+
+  {
+    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 ;
+
+    stralloc_shrink(&storage) ;
+    while (i--)
+      sbearssl_ta_to(genalloc_s(sbearssl_ta, &tas) + i, btas + i, storage.s) ;
+    genalloc_free(sbearssl_ta, &tas) ;
+    br_ssl_client_init_full(&cc, &xc, btas, talen) ;
+    random_string((char *)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))) ;
+    if (!sbearssl_x509_minimal_set_tain(&xc, &STAMP))
+      strerr_diefu1sys(111, "initialize validation time") ;
+
+    sbearssl_run(&cc.eng, fds, tto, options, verbosity, cb, &cbarg) ;
+  }
+}