svn commit: r367442 - in head/sys: kern sys

[Kyle Evans]

Author: kevans
Date: Sat Nov  7 04:10:23 2020
New Revision: 367442
URL: https://svnweb.freebsd.org/changeset/base/367442

Log:
  imgact_binmisc: validate flags coming from userland
  
  We may want to reserve bits in the future for kernel-only use, so start
  rejecting any that aren't the two that we're currently expecting from
  userland.
  
  MFC after:	1 week

Modified:
  head/sys/kern/imgact_binmisc.c
  head/sys/sys/imgact_binmisc.h

Modified: head/sys/kern/imgact_binmisc.c
==============================================================================
--- head/sys/kern/imgact_binmisc.c	Sat Nov  7 03:43:45 2020	(r367441)
+++ head/sys/kern/imgact_binmisc.c	Sat Nov  7 04:10:23 2020	(r367442)
@@ -434,6 +434,8 @@ sysctl_kern_binmisc(SYSCTL_HANDLER_ARGS)
 			return (error);
 		if (IBE_VERSION != xbe.xbe_version)
 			return (EINVAL);
+		if ((xbe.xbe_flags & ~IBF_VALID_UFLAGS) != 0)
+			return (EINVAL);
 		if (interp_list_entry_count == IBE_MAX_ENTRIES)
 			return (ENOSPC);
 		error = imgact_binmisc_add_entry(&xbe);

Modified: head/sys/sys/imgact_binmisc.h
==============================================================================
--- head/sys/sys/imgact_binmisc.h	Sat Nov  7 03:43:45 2020	(r367441)
+++ head/sys/sys/imgact_binmisc.h	Sat Nov  7 04:10:23 2020	(r367442)
@@ -53,6 +53,8 @@
 #define	IBF_ENABLED	0x0001	/* Entry is active. */
 #define	IBF_USE_MASK	0x0002	/* Use mask on header magic field. */
 
+#define	IBF_VALID_UFLAGS	0x0003	/* Bits allowed from userland. */
+
 /*
  * Used with sysctlbyname() to pass imgact bin misc entries in and out of the
  * kernel.