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Date:      Tue, 17 Sep 2013 20:48:20 +0000 (UTC)
From:      Jilles Tjoelker <jilles@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r255657 - head/sys/compat/freebsd32
Message-ID:  <201309172048.r8HKmKSe081542@svn.freebsd.org>
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Author: jilles
Date: Tue Sep 17 20:48:19 2013
New Revision: 255657
URL: http://svnweb.freebsd.org/changeset/base/255657

Log:
  Disallow cap_enter() in freebsd32 compatibility mode.
  
  The freebsd32 compatibility mode (for running 32-bit binaries on 64-bit
  kernels) does not currently allow any system calls in capability mode, but
  still permits cap_enter(). As a result, 32-bit binaries on 64-bit kernels
  that use capability mode do not work (they crash after being disallowed to
  call sys_exit()). Affected binaries include dhclient and uniq. The latter's
  crashes cause obscure build failures.
  
  This commit makes freebsd32 cap_enter() fail with [ENOSYS], as if capability
  mode was not compiled in. Applications deal with this by doing their work
  without capability mode.
  
  This commit does not fix the uncommon situation where a 64-bit process
  enters capability mode and then executes a 32-bit binary using fexecve().
  
  This commit should be reverted when allowing the necessary freebsd32 system
  calls in capability mode.
  
  Reviewed by:	pjd
  Approved by:	re (hrs)

Modified:
  head/sys/compat/freebsd32/freebsd32_capability.c
  head/sys/compat/freebsd32/syscalls.master

Modified: head/sys/compat/freebsd32/freebsd32_capability.c
==============================================================================
--- head/sys/compat/freebsd32/freebsd32_capability.c	Tue Sep 17 20:33:42 2013	(r255656)
+++ head/sys/compat/freebsd32/freebsd32_capability.c	Tue Sep 17 20:48:19 2013	(r255657)
@@ -49,6 +49,18 @@ __FBSDID("$FreeBSD$");
 MALLOC_DECLARE(M_FILECAPS);
 
 int
+freebsd32_cap_enter(struct thread *td,
+    struct freebsd32_cap_enter_args *uap)
+{
+
+	/*
+	 * We do not have an equivalent of capabilities.conf for freebsd32
+	 * compatibility, so do not allow capability mode for now.
+	 */
+	return (ENOSYS);
+}
+
+int
 freebsd32_cap_ioctls_limit(struct thread *td,
     struct freebsd32_cap_ioctls_limit_args *uap)
 {
@@ -136,6 +148,14 @@ out:
 #else /* !CAPABILITIES */
 
 int
+freebsd32_cap_enter(struct thread *td,
+    struct freebsd32_cap_enter_args *uap)
+{
+
+	return (ENOSYS);
+}
+
+int
 freebsd32_cap_ioctls_limit(struct thread *td,
     struct freebsd32_cap_ioctls_limit_args *uap)
 {

Modified: head/sys/compat/freebsd32/syscalls.master
==============================================================================
--- head/sys/compat/freebsd32/syscalls.master	Tue Sep 17 20:33:42 2013	(r255656)
+++ head/sys/compat/freebsd32/syscalls.master	Tue Sep 17 20:48:19 2013	(r255657)
@@ -973,7 +973,7 @@
 514	AUE_NULL	OBSOL	cap_new
 515	AUE_CAP_RIGHTS_GET	NOPROTO	{ int __cap_rights_get(int version, \
 				    int fd, cap_rights_t *rightsp); }
-516	AUE_CAP_ENTER	NOPROTO	{ int cap_enter(void); }
+516	AUE_CAP_ENTER	STD	{ int freebsd32_cap_enter(void); }
 517	AUE_CAP_GETMODE	NOPROTO	{ int cap_getmode(u_int *modep); }
 518	AUE_PDFORK	NOPROTO	{ int pdfork(int *fdp, int flags); }
 519	AUE_PDKILL	NOPROTO	{ int pdkill(int fd, int signum); }

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