netdev - Re: [PATCH] net: off by one, try #2

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Date:	Wed, 11 Feb 2009 15:22:52 +0100
From:	Roel Kluin <roel.kluin@...il.com>
To:	Jarek Poplawski <jarkao2@...il.com>
CC:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] net: off by one, try #2

>> With while (x++ < n) { ... } x can reach n+1.
> 
> Yes, but it looks like here is even more...
> i is also misused here and array can be overriden, so additional
> break/return is needed.

Thanks, is this how it should be?
-------------------->8----------------8<-----------------------

With while (x++ < n) { ... } x can reach n+1. As Jarek Poplawski pointed out, array
pcb->data.raw was not correctly used.

Signed-off-by: Roel Kluin <roel.kluin@...il.com>
---
diff --git a/drivers/net/3c505.c b/drivers/net/3c505.c
index 6124605..4cf3050 100644
--- a/drivers/net/3c505.c
+++ b/drivers/net/3c505.c
@@ -497,12 +497,15 @@ static bool receive_pcb(struct net_device *dev, pcb_struct * pcb)
 	do {
 		j = 0;
 		while (((stat = get_status(dev->base_addr)) & ACRF) == 0 && j++ < 20000);
-		pcb->data.raw[i++] = inb_command(dev->base_addr);
-		if (i > MAX_PCB_DATA)
-			INVALID_PCB_MSG(i);
-	} while ((stat & ASF_PCB_MASK) != ASF_PCB_END && j < 20000);
+		pcb->data.raw[i] = inb_command(dev->base_addr);
+	} while (++i < MAX_PCB_DATA && (stat & ASF_PCB_MASK) != ASF_PCB_END && j <= 20000);
+
 	spin_unlock_irqrestore(&adapter->lock, flags);
-	if (j >= 20000) {
+	if (i >= MAX_PCB_DATA) {
+		INVALID_PCB_MSG(i);
+		return false;
+	}
+	if (j > 20000) {
 		TIMEOUT_MSG(__LINE__);
 		return false;
 	}
--
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