[src/trunk]: src/sys/dev avoid variable array stack allocation by enforcing a...

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

details:   https://anonhg.NetBSD.org/src/rev/87408a9ea8c7
branches:  trunk
changeset: 748922:87408a9ea8c7
user:      christos <christos%NetBSD.org@localhost>
date:      Tue Nov 10 20:05:50 2009 +0000

description:
avoid variable array stack allocation by enforcing and allocating always the
maximum.

diffstat:

 sys/dev/cgd.c    |  28 ++++++++++++++++++----------
 sys/dev/cgdvar.h |   5 ++++-
 2 files changed, 22 insertions(+), 11 deletions(-)

diffs (107 lines):

diff -r 7b93cb50b341 -r 87408a9ea8c7 sys/dev/cgd.c
--- a/sys/dev/cgd.c     Tue Nov 10 18:19:46 2009 +0000
+++ b/sys/dev/cgd.c     Tue Nov 10 20:05:50 2009 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cgd.c,v 1.61 2009/11/10 16:49:53 tron Exp $ */
+/* $NetBSD: cgd.c,v 1.62 2009/11/10 20:05:50 christos Exp $ */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.61 2009/11/10 16:49:53 tron Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.62 2009/11/10 20:05:50 christos Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -48,6 +48,7 @@
 #include <sys/fcntl.h>
 #include <sys/vnode.h>
 #include <sys/conf.h>
+#include <sys/syslog.h>
 
 #include <dev/dkvar.h>
 #include <dev/cgdvar.h>
@@ -183,15 +184,16 @@
                return;
        }
 
-       cgd_softc = (void *)malloc(num * sizeof(*cgd_softc), M_DEVBUF, M_NOWAIT);
+       cgd_softc = malloc(num * sizeof(*cgd_softc), M_DEVBUF, M_NOWAIT);
        if (!cgd_softc) {
-               printf("WARNING: unable to malloc(9) memory for crypt disks\n");
+               DPRINTF_FOLLOW(("WARNING: unable to malloc(9) memory for %d "
+                   "crypt disks\n", num));
                DIAGPANIC(("cgdattach: cannot malloc(9) enough memory"));
                return;
        }
 
        numcgd = num;
-       for (i=0; i<num; i++)
+       for (i = 0; i < num; i++)
                cgdsoftc_init(&cgd_softc[i], i);
 }
 
@@ -362,7 +364,8 @@
            nbp->b_bcount));
        if (nbp->b_error != 0) {
                obp->b_error = nbp->b_error;
-               printf("%s: error %d\n", dksc->sc_xname, obp->b_error);
+               DPRINTF(CGDB_IO, ("%s: error %d\n", dksc->sc_xname,
+                   obp->b_error));
        }
 
        /* Perform the decryption if we are reading.
@@ -572,6 +575,12 @@
        cs->sc_cdata.cf_mode = encblkno[i].v;
        cs->sc_cdata.cf_priv = cs->sc_cfuncs->cf_init(ci->ci_keylen, inbuf,
            &cs->sc_cdata.cf_blocksize);
+       if (cs->sc_cdata.cf_blocksize > CGD_MAXBLOCKSIZE) {
+           log(LOG_WARNING, "cgd: Disallowed cipher with blocksize %zu > %u\n",
+               cs->sc_data.cf_blocksize, CGD_MAXBLOCKSIZE);
+           cs->sc_cdata.cf_priv = NULL;
+       }
+               
        /*
         * The blocksize is supposed to be in bytes. Unfortunately originally
         * it was expressed in bits. For compatibility we maintain encblkno
@@ -580,7 +589,6 @@
        cs->sc_cdata.cf_blocksize /= encblkno[i].d;
        (void)memset(inbuf, 0, MAX_KEYSIZE);
        if (!cs->sc_cdata.cf_priv) {
-               printf("cgd: unable to initialize cipher\n");
                ret = EINVAL;           /* XXX is this the right error? */
                goto bail;
        }
@@ -775,9 +783,9 @@
        struct iovec    dstiov[2];
        struct iovec    srciov[2];
        size_t          blocksize = cs->sc_cdata.cf_blocksize;
-       char            sink[blocksize];
-       char            zero_iv[blocksize];
-       char            blkno_buf[blocksize];
+       char            sink[CGD_MAXBLOCKSIZE];
+       char            zero_iv[CGD_MAXBLOCKSIZE];
+       char            blkno_buf[CGD_MAXBLOCKSIZE];
 
        DPRINTF_FOLLOW(("cgd_cipher() dir=%d\n", dir));
 
diff -r 7b93cb50b341 -r 87408a9ea8c7 sys/dev/cgdvar.h
--- a/sys/dev/cgdvar.h  Tue Nov 10 18:19:46 2009 +0000
+++ b/sys/dev/cgdvar.h  Tue Nov 10 20:05:50 2009 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cgdvar.h,v 1.12 2008/09/12 16:51:55 christos Exp $ */
+/* $NetBSD: cgdvar.h,v 1.13 2009/11/10 20:05:50 christos Exp $ */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -87,4 +87,7 @@
 #define CGDIOCSET      _IOWR('F', 18, struct cgd_ioctl)
 #define CGDIOCCLR      _IOW('F', 19, struct cgd_ioctl)
 
+/* Maximum block sized to be used by the ciphers */
+#define CGD_MAXBLOCKSIZE       128
+
 #endif /* _DEV_CGDVAR_H_ */