[src/trunk]: src/sys/netsmb Plug another overflow: refuse bogus sa_len from u...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/fbf61d0e20b2
branches:  trunk
changeset: 825695:fbf61d0e20b2
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Jul 28 14:37:27 2017 +0000

description:
Plug another overflow: refuse bogus sa_len from user.

diffstat:

 sys/netsmb/smb_subr.c |  33 +++++++++++++++++++++++++++++++--
 sys/netsmb/smb_subr.h |   3 ++-
 sys/netsmb/smb_usr.c  |  24 ++++++++++--------------
 3 files changed, 43 insertions(+), 17 deletions(-)

diffs (122 lines):

diff -r f3e5b4e96e93 -r fbf61d0e20b2 sys/netsmb/smb_subr.c
--- a/sys/netsmb/smb_subr.c     Fri Jul 28 14:26:50 2017 +0000
+++ b/sys/netsmb/smb_subr.c     Fri Jul 28 14:37:27 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: smb_subr.c,v 1.37 2014/11/15 18:52:45 nakayama Exp $   */
+/*     $NetBSD: smb_subr.c,v 1.38 2017/07/28 14:37:27 riastradh Exp $  */
 
 /*
  * Copyright (c) 2000-2001 Boris Popov
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: smb_subr.c,v 1.37 2014/11/15 18:52:45 nakayama Exp $");
+__KERNEL_RCSID(0, "$NetBSD: smb_subr.c,v 1.38 2017/07/28 14:37:27 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -380,3 +380,32 @@
                memcpy(sa2, sa, sa->sa_len);
        return sa2;
 }
+
+int
+dup_sockaddr_copyin(struct sockaddr **ksap, struct sockaddr *usa,
+    size_t usalen)
+{
+       struct sockaddr *ksa;
+
+       /* Make sure user provided enough data for a generic sockaddr.  */
+       if (usalen < sizeof(*ksa))
+               return EINVAL;
+
+       /* Don't let the user overfeed us.  */
+       usalen = MIN(usalen, sizeof(struct sockaddr_storage));
+
+       /* Copy the buffer in from userland.  */
+       ksa = smb_memdupin(usa, usalen);
+       if (ksa == NULL)
+               return ENOMEM;
+
+       /* Make sure the user's idea of sa_len is reasonable.  */
+       if (ksa->sa_len > usalen) {
+               smb_memfree(ksa);
+               return EINVAL;
+       }
+
+       /* Success!  */
+       *ksap = ksa;
+       return 0;
+}
diff -r f3e5b4e96e93 -r fbf61d0e20b2 sys/netsmb/smb_subr.h
--- a/sys/netsmb/smb_subr.h     Fri Jul 28 14:26:50 2017 +0000
+++ b/sys/netsmb/smb_subr.h     Fri Jul 28 14:37:27 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: smb_subr.h,v 1.21 2012/03/13 18:41:01 elad Exp $       */
+/*     $NetBSD: smb_subr.h,v 1.22 2017/07/28 14:37:27 riastradh Exp $  */
 
 /*
  * Copyright (c) 2000-2001, Boris Popov
@@ -128,5 +128,6 @@
 #endif
 
 struct sockaddr *dup_sockaddr(struct sockaddr *, int);
+int dup_sockaddr_copyin(struct sockaddr **, struct sockaddr *, size_t);
 
 #endif /* !_NETSMB_SMB_SUBR_H_ */
diff -r f3e5b4e96e93 -r fbf61d0e20b2 sys/netsmb/smb_usr.c
--- a/sys/netsmb/smb_usr.c      Fri Jul 28 14:26:50 2017 +0000
+++ b/sys/netsmb/smb_usr.c      Fri Jul 28 14:37:27 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: smb_usr.c,v 1.17 2017/07/28 14:20:46 riastradh Exp $   */
+/*     $NetBSD: smb_usr.c,v 1.18 2017/07/28 14:37:27 riastradh Exp $   */
 
 /*
  * Copyright (c) 2000-2001 Boris Popov
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: smb_usr.c,v 1.17 2017/07/28 14:20:46 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: smb_usr.c,v 1.18 2017/07/28 14:37:27 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/malloc.h>
@@ -65,6 +65,7 @@
 smb_usr_vc2spec(struct smbioc_ossn *dp, struct smb_vcspec *spec)
 {
        int flags = 0;
+       int error;
 
        memset(spec, 0, sizeof(*spec));
        if (dp->ioc_user[0] == 0)
@@ -75,21 +76,16 @@
                SMBERROR(("no local charset ?\n"));
                return EINVAL;
        }
-       if (dp->ioc_svlen < sizeof(*spec->sap))
-               return EINVAL;
 
-       spec->sap = smb_memdupin(dp->ioc_server, dp->ioc_svlen);
-       if (spec->sap == NULL)
-               return ENOMEM;
+       error = dup_sockaddr_copyin(&spec->sap, dp->ioc_server, dp->ioc_svlen);
+       if (error)
+               return error;
        if (dp->ioc_local) {
-               if (dp->ioc_lolen < sizeof(*spec->lap)) {
+               error = dup_sockaddr_copyin(&spec->lap, dp->ioc_local,
+                   dp->ioc_lolen);
+               if (error) {
                        smb_usr_vcspec_free(spec);
-                       return ENOMEM;
-               }
-               spec->lap = smb_memdupin(dp->ioc_local, dp->ioc_lolen);
-               if (spec->lap == NULL) {
-                       smb_usr_vcspec_free(spec);
-                       return ENOMEM;
+                       return error;
                }
        }
        spec->srvname = dp->ioc_srvname;