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, 43 insertions, 0 deletions

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) ;
+}