pcmcia: fix read buffer overflow

If count > 0 and dev->rlen == dev->rpos and dev->proto == 0 then we read and write dev->rbuf[-1]; Signed-off-by: Roel Kluin <[email protected]> Cc: Harald Welte <[email protected]> Cc: Dominik Brodowski <[email protected]> Cc: Greg KH <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
blinkosm · Sep 22, 2009 · 470967d · 470967d
1 parent 734f3fa
commit 470967d
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c
@@ -1017,7 +1017,7 @@ static ssize_t cmm_read(struct file *filp, __user char *buf, size_t count,
 		}
 	}
 
-	if (dev->proto == 0 && count > dev->rlen - dev->rpos) {
+	if (dev->proto == 0 && count > dev->rlen - dev->rpos && i) {
 		DEBUGP(4, dev, "T=0 and count > buffer\n");
 		dev->rbuf[i] = dev->rbuf[i - 1];
 		dev->rbuf[i - 1] = dev->procbyte;