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Fix a bug in the wt driver that could cause memory corruption.

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Closes PR # kern/1065.

While i was at it, also reject IO requests that are not an integer
multiple of the device blocksize.

Submitted by:	vak@crox.net.kiae.su (Serge V.Vakulenko)
Confirmed by:	Georg-W. Koltermann (gwk@cray.com)
This commit is contained in:
Joerg Wunsch 1996-12-23 01:53:13 +00:00
parent 553435cfa7
commit 2c966b7fdc
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=20835
1 changed files with 16 additions and 8 deletions
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24
sys/i386/isa/wt.c
View File

@ -20,7 +20,7 @@
* the original CMU copyright notice.
*
* Version 1.3, Thu Nov 11 12:09:13 MSK 1993
* $Id: wt.c,v 1.34 1996/08/31 14:47:45 bde Exp $
* $Id: wt.c,v 1.35 1996/09/06 23:08:15 phk Exp $
*
*/
@ -523,13 +523,20 @@ wtstrategy (struct buf *bp)
int s;
bp->b_resid = bp->b_bcount;
if (u >= NWT || t->type == UNKNOWN)
goto errxit;
if (u >= NWT || t->type == UNKNOWN) {
bp->b_error = ENXIO;
goto err2xit;
}
/* at file marks and end of tape, we just return '0 bytes available' */
if (t->flags & TPVOL)
goto xit;
if (bp->b_bcount % t->bsize != 0) {
bp->b_error = EINVAL;
goto err2xit;
}
if (bp->b_flags & B_READ) {
/* Check read access and no previous write to this tape. */
if (! (t->flags & TPREAD) || (t->flags & TPWANY))
@ -576,8 +583,8 @@ wtstrategy (struct buf *bp)
splx (s);
if (t->flags & TPEXCEP) {
errxit: bp->b_flags |= B_ERROR;
bp->b_error = EIO;
errxit: bp->b_error = EIO;
err2xit: bp->b_flags |= B_ERROR;
}
xit: biodone (bp);
return;
@ -636,8 +643,6 @@ wtintr (int u)
TRACE (("unexpected interrupt\n"));
return;
}
t->flags &= ~TPACTIVE;
t->dmacount += t->bsize; /* increment counter */
/*
* Clean up dma.
@ -650,6 +655,10 @@ wtintr (int u)
} else
isa_dmadone (t->dmaflags, t->dmavaddr, t->bsize, t->chan);
t->flags &= ~TPACTIVE;
t->dmacount += t->bsize;
t->dmavaddr = (char *)t->dmavaddr + t->bsize;
/*
* On exception, check for end of file and end of volume.
*/
@ -665,7 +674,6 @@ wtintr (int u)
}
if (t->dmacount < t->dmatotal) { /* continue i/o */
t->dmavaddr = (char *)t->dmavaddr + t->bsize;
wtdma (t);
TRACE (("continue i/o, %d\n", t->dmacount));
return;