Apply by doing:
        cd /usr/src
        patch -p0 < 020_procfs.patch

And then rebuild your kernel.

Index: sys/miscfs/procfs/procfs_cmdline.c
===================================================================
RCS file: /cvs/src/sys/miscfs/procfs/procfs_cmdline.c,v
retrieving revision 1.3
retrieving revision 1.3.10.1
diff -u -p -r1.3 -r1.3.10.1
--- sys/miscfs/procfs/procfs_cmdline.c	6 Nov 2001 19:53:20 -0000	1.3
+++ sys/miscfs/procfs/procfs_cmdline.c	13 May 2004 03:08:31 -0000	1.3.10.1
@@ -83,11 +83,10 @@ procfs_docmdline(curp, p, pfs, uio)
 	 */
 	if (P_ZOMBIE(p) || (p->p_flag & P_SYSTEM) != 0) {
                 len = snprintf(arg, PAGE_SIZE, "(%s)", p->p_comm);
-                xlen = len - uio->uio_offset;
-                if (xlen <= 0) 
+                if (uio->uio_offset >= (off_t)len)
                         error = 0;
                 else
-                        error = uiomove(arg, xlen, uio);
+                        error = uiomove(arg, len - uio->uio_offset, uio);
 		
                 free(arg, M_TEMP);
                 return (error);	
Index: sys/miscfs/procfs/procfs_fpregs.c
===================================================================
RCS file: /cvs/src/sys/miscfs/procfs/procfs_fpregs.c,v
retrieving revision 1.6
retrieving revision 1.6.2.1
diff -u -p -r1.6 -r1.6.2.1
--- sys/miscfs/procfs/procfs_fpregs.c	2 Jun 2003 23:28:11 -0000	1.6
+++ sys/miscfs/procfs/procfs_fpregs.c	13 May 2004 03:08:31 -0000	1.6.2.1
@@ -63,7 +63,7 @@ procfs_dofpregs(curp, p, pfs, uio)
 		return (error);
 
 	kl = sizeof(r);
-	kv = (char *) &r;
+	kv = (char *)&r;
 
 	kv += uio->uio_offset;
 	kl -= uio->uio_offset;
@@ -72,7 +72,7 @@ procfs_dofpregs(curp, p, pfs, uio)
 
 	PHOLD(p);
 
-	if (kl < 0)
+	if (uio->uio_offset > (off_t)sizeof(r))
 		error = EINVAL;
 	else
 		error = process_read_fpregs(p, &r);
Index: sys/miscfs/procfs/procfs_linux.c
===================================================================
RCS file: /cvs/src/sys/miscfs/procfs/procfs_linux.c,v
retrieving revision 1.4
retrieving revision 1.4.10.1
diff -u -p -r1.4 -r1.4.10.1
--- sys/miscfs/procfs/procfs_linux.c	6 Nov 2001 19:53:20 -0000	1.4
+++ sys/miscfs/procfs/procfs_linux.c	13 May 2004 03:08:31 -0000	1.4.10.1
@@ -89,16 +89,13 @@ procfs_domeminfo(struct proc *curp, stru
 		PGTOKB(uvmexp.swpages),
 		PGTOKB(uvmexp.swpages - uvmexp.swpginuse));
 
-	if (len == 0)
+	if (len == 0 || len <= uio->uio_offset || uio->uio_resid == 0)
 		return 0;
 
 	len -= uio->uio_offset;
 	cp = buf + uio->uio_offset;
 	len = imin(len, uio->uio_resid);
-	if (len <= 0)
-		error = 0;
-	else
-		error = uiomove(cp, len, uio);
+	error = uiomove(cp, len, uio);
 	return error;
 }
 
@@ -113,7 +110,7 @@ procfs_docpuinfo(struct proc *curp, stru
 	if (procfs_getcpuinfstr(buf, &len) < 0)
 		return EIO;
 
-	if (len == 0)
+	if (len == 0 || uio->uio_offset > sizeof(buf))
 		return 0;
 
 	len -= uio->uio_offset;
Index: sys/miscfs/procfs/procfs_regs.c
===================================================================
RCS file: /cvs/src/sys/miscfs/procfs/procfs_regs.c,v
retrieving revision 1.7
retrieving revision 1.7.2.1
diff -u -p -r1.7 -r1.7.2.1
--- sys/miscfs/procfs/procfs_regs.c	2 Jun 2003 23:28:11 -0000	1.7
+++ sys/miscfs/procfs/procfs_regs.c	13 May 2004 03:08:31 -0000	1.7.2.1
@@ -62,7 +62,7 @@ procfs_doregs(curp, p, pfs, uio)
 		return (error);
 
 	kl = sizeof(r);
-	kv = (char *) &r;
+	kv = (char *)&r;
 
 	kv += uio->uio_offset;
 	kl -= uio->uio_offset;
@@ -71,7 +71,7 @@ procfs_doregs(curp, p, pfs, uio)
 
 	PHOLD(p);
 
-	if (kl < 0)
+	if (uio->uio_offset > (off_t)sizeof(r))
 		error = EINVAL;
 	else
 		error = process_read_regs(p, &r);
Index: sys/miscfs/procfs/procfs_status.c
===================================================================
RCS file: /cvs/src/sys/miscfs/procfs/procfs_status.c,v
retrieving revision 1.6
retrieving revision 1.6.2.1
diff -u -p -r1.6 -r1.6.2.1
--- sys/miscfs/procfs/procfs_status.c	2 Jun 2003 23:28:11 -0000	1.6
+++ sys/miscfs/procfs/procfs_status.c	13 May 2004 03:08:31 -0000	1.6.2.1
@@ -164,16 +164,16 @@ procfs_dostatus(curp, p, pfs, uio)
 
 	len = procfs_stat_gen(p, NULL, 0);
 	ps = malloc(len, M_TEMP, M_WAITOK);
-	(void) procfs_stat_gen(p, ps, len);
+	len = procfs_stat_gen(p, ps, len);
 
-	len -= uio->uio_offset;
-	len = imin(len, uio->uio_resid);
-	if (len <= 0)
+	if (len <= uio->uio_offset)
 		error = 0;
-	else
+	else {
+		len -= uio->uio_offset;
+		len = imin(len, uio->uio_resid);
 		error = uiomove(ps + uio->uio_offset, len, uio);
+	}
 
 	free(ps, M_TEMP);
 	return (error);
 }
-
Index: sys/miscfs/procfs/procfs_subr.c
===================================================================
RCS file: /cvs/src/sys/miscfs/procfs/procfs_subr.c,v
retrieving revision 1.20
retrieving revision 1.20.2.1
diff -u -p -r1.20 -r1.20.2.1
--- sys/miscfs/procfs/procfs_subr.c	11 Aug 2003 10:08:04 -0000	1.20
+++ sys/miscfs/procfs/procfs_subr.c	13 May 2004 03:08:31 -0000	1.20.2.1
@@ -214,6 +214,8 @@ procfs_rw(v)
 	/* Do not permit games to be played with init(8) */
 	if (p->p_pid == 1 && securelevel > 0 && uio->uio_rw == UIO_WRITE)
 		return (EPERM);
+	if (uio->uio_offset < 0)
+		return (EINVAL);
 
 	switch (pfs->pfs_type) {
 	case Pnote: