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Made msgbuf range checking more robust and clean.

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This commit is contained in:
David Greenman 1995-08-07 07:58:23 +00:00
parent 1e890b056a
commit 6c8897cf98
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=9979
3 changed files with 13 additions and 24 deletions
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17
sys/kern/subr_log.c
View file

@ -31,7 +31,7 @@
* SUCH DAMAGE.
*
* @(#)subr_log.c 8.1 (Berkeley) 6/10/93
* $Id: subr_log.c,v 1.7 1995/04/29 11:36:47 jkh Exp $
* $Id: subr_log.c,v 1.8 1995/05/30 08:05:52 rgrimes Exp $
*/
/*
@ -73,19 +73,6 @@ logopen(dev, flags, mode, p)
return (EBUSY);
log_open = 1;
logsoftc.sc_pgid = p->p_pid; /* signal process only */
/*
* Potential race here with putchar() but since putchar should be
* called by autoconf, msg_magic should be initialized by the time
* we get here.
*/
if (mbp->msg_magic != MSG_MAGIC) {
register int i;
mbp->msg_magic = MSG_MAGIC;
mbp->msg_bufx = mbp->msg_bufr = 0;
for (i=0; i < MSG_BSIZE; i++)
mbp->msg_bufc[i] = 0;
}
return (0);
}
@ -142,7 +129,7 @@ logread(dev, uio, flag)
if (error)
break;
mbp->msg_bufr += l;
if (mbp->msg_bufr < 0 || mbp->msg_bufr >= MSG_BSIZE)
if (mbp->msg_bufr >= MSG_BSIZE)
mbp->msg_bufr = 0;
}
return (error);

8
sys/kern/subr_prf.c
View file

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)subr_prf.c 8.3 (Berkeley) 1/21/94
* $Id: subr_prf.c,v 1.14 1995/06/14 07:55:07 bde Exp $
* $Id: subr_prf.c,v 1.15 1995/08/06 22:00:17 davidg Exp $
*/
#include <sys/param.h>
@ -504,8 +504,10 @@ putchar(c, flags, tp)
if ((flags & TOLOG) &&
c != '\0' && c != '\r' && c != 0177 && msgbufmapped) {
mbp = msgbufp;
if (mbp->msg_magic != MSG_MAGIC) {
bzero((caddr_t)mbp, sizeof(*mbp));
if (mbp->msg_magic != MSG_MAGIC ||
mbp->msg_bufx >= MSG_BSIZE ||
mbp->msg_bufr >= MSG_BSIZE) {
bzero(mbp, sizeof(struct msgbuf));
mbp->msg_magic = MSG_MAGIC;
}
mbp->msg_bufc[mbp->msg_bufx++] = c;

12
sys/sys/msgbuf.h
View file

@ -31,19 +31,19 @@
* SUCH DAMAGE.
*
* @(#)msgbuf.h 8.1 (Berkeley) 6/2/93
* $Id: msgbuf.h,v 1.4 1994/08/21 04:41:54 paul Exp $
* $Id: msgbuf.h,v 1.5 1995/03/16 18:16:21 bde Exp $
*/
#ifndef _SYS_MSGBUF_H_
#define _SYS_MSGBUF_H_
#define MSG_BSIZE (4096 - 3 * sizeof(long))
#define MSG_BSIZE (4096 - 3 * sizeof(unsigned int))
struct msgbuf {
#define MSG_MAGIC 0x063061
long msg_magic;
long msg_bufx; /* write pointer */
long msg_bufr; /* read pointer */
char msg_bufc[MSG_BSIZE]; /* buffer */
unsigned int msg_magic;
unsigned int msg_bufx; /* write pointer */
unsigned int msg_bufr; /* read pointer */
char msg_bufc[MSG_BSIZE]; /* buffer */
};
#ifdef KERNEL
extern int msgbufmapped;