[6.0] 4d2c0c543 support for vmod_unix on solar-ish OSes

[Dridi Boukelmoune]

commit 4d2c0c543a0ffc24f810111cd42dd8e435815466
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Thu Apr 5 13:58:19 2018 +0200

    support for vmod_unix on solar-ish OSes
    
    note on jail_solaris:
    
    ideally, vmods could tell the jails about privileges they require, but
    for now (and because vmod_unix lives in varnish-cache), just add the
    required privilege to the permitted set.
    
    I have also considered the option to add additional privileges via the
    -j argument (and actually would still want to add that somewhen), but
    for this purpose, varnish should really DTRT by default.
    
    note on priv_allocset:
    
    Most of the sun folk had proven to be good interface designers, but
    an API which requires dynamic allocation/deallocation really does not
    play well with my efficiency fetish. So good we got library
    constructors/destructors.
    
    note on getpeerucred:
    
    basically the same thing, but this time they at least added
    ucred_size(). Not intended for use like this, but anyway....

diff --git a/bin/varnishd/mgt/mgt_jail_solaris.c b/bin/varnishd/mgt/mgt_jail_solaris.c
index ef80c909b..dc1921297 100644
--- a/bin/varnishd/mgt/mgt_jail_solaris.c
+++ b/bin/varnishd/mgt/mgt_jail_solaris.c
@@ -356,6 +356,8 @@ vjs_add_permitted(priv_set_t *pset, enum jail_gen_e jge)
 	case JAILG_SUBPROC_VCLLOAD:
 		break;
 	case JAILG_SUBPROC_WORKER:
+		/* vmod_unix getpeerucred() */
+		AZ(priv_addset(pset, PRIV_PROC_INFO));
 		break;
 	default:
 		INCOMPL();
diff --git a/configure.ac b/configure.ac
index ad2850737..2e25adf05 100644
--- a/configure.ac
+++ b/configure.ac
@@ -217,6 +217,7 @@ AC_CHECK_FUNCS([fallocate])
 AC_CHECK_FUNCS([closefrom])
 AC_CHECK_FUNCS([sigaltstack])
 AC_CHECK_FUNCS([getpeereid])
+AC_CHECK_FUNCS([getpeerucred])
 
 save_LIBS="${LIBS}"
 LIBS="${PTHREAD_LIBS}"
diff --git a/lib/libvmod_unix/cred_compat.h b/lib/libvmod_unix/cred_compat.h
index 6a79636f5..3c5ff080e 100644
--- a/lib/libvmod_unix/cred_compat.h
+++ b/lib/libvmod_unix/cred_compat.h
@@ -25,8 +25,6 @@
  *
  */
 
-#include "config.h"
-
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <errno.h>
@@ -37,11 +35,35 @@
 
 #if defined(HAVE_GETPEERUCRED)
 #include <ucred.h>
+# if defined(HAVE_SETPPRIV)
+# include <priv.h>
+static priv_set_t *priv_proc_info = NULL;
+# endif
 #endif
 
 #define CREDS_FAIL -1
 #define NOT_SUPPORTED -2
 
+#if defined(HAVE_GETPEERUCRED) && defined(HAVE_SETPPRIV)
+static void __attribute__((constructor))
+cred_compat_init(void)
+{
+	AZ(priv_proc_info);
+	priv_proc_info = priv_allocset();
+	AN(priv_proc_info);
+	AZ(priv_addset(priv_proc_info, PRIV_PROC_INFO));
+}
+
+static void __attribute__((destructor))
+cred_compat_fini(void)
+{
+	if (priv_proc_info == NULL)
+		return;
+	priv_freeset(priv_proc_info);
+	priv_proc_info = NULL;
+}
+#endif
+
 static int
 get_ids(int fd, uid_t *uid, gid_t *gid)
 {
@@ -65,6 +87,33 @@ get_ids(int fd, uid_t *uid, gid_t *gid)
 		return (CREDS_FAIL);
 	return (0);
 
+#elif defined(HAVE_GETPEERUCRED)
+	char buf[ucred_size()];
+	ucred_t *ucredp = (ucred_t *)buf;
+
+# if defined(HAVE_SETPPRIV)
+	priv_set_t *priv = NULL;
+
+	errno = 0;
+	if (! priv_ineffect(PRIV_PROC_INFO)) {
+		priv = priv_proc_info;
+		if (setppriv(PRIV_ON, PRIV_EFFECTIVE, priv))
+			return (CREDS_FAIL);
+	}
+# endif
+
+	errno = 0;
+	if (getpeerucred(fd, &ucredp))
+		return (CREDS_FAIL);
+	*uid = ucred_getruid(ucredp);
+	*gid = ucred_getrgid(ucredp);
+
+# if defined(HAVE_SETPPRIV)
+	if (priv != NULL)
+		AZ(setppriv(PRIV_OFF, PRIV_EFFECTIVE, priv)); // waive
+# endif
+
+	return (0);
 #else
 	(void) fd;
 	(void) uid;
diff --git a/lib/libvmod_unix/vmod_unix.c b/lib/libvmod_unix/vmod_unix.c
index ee1f3e002..f51c10883 100644
--- a/lib/libvmod_unix/vmod_unix.c
+++ b/lib/libvmod_unix/vmod_unix.c
@@ -25,7 +25,7 @@
  *
  */
 
-#include "cred_compat.h"
+#include "config.h"
 
 #include <pwd.h>
 #include <grp.h>
@@ -35,6 +35,7 @@
 #include "vcl.h"
 #include "common/heritage.h"
 
+#include "cred_compat.h"
 #include "vcc_if.h"
 
 #define FAIL(ctx, msg) \