netdev - Re: [PATCH] eexpress: Read buffer overflow

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Message-ID: <4A704C40.1070606@gmail.com>
Date:	Wed, 29 Jul 2009 15:18:56 +0200
From:	Roel Kluin <roel.kluin@...il.com>
To:	Jarek Poplawski <jarkao2@...il.com>
CC:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
	akpm@...ux-foundation.org
Subject: Re: [PATCH] eexpress: Read buffer overflow

start_code is 69 words, but the code always writes a multiple of 16 words,
so the last 11 words written are outside the array.

Signed-off-by: Roel Kluin <roel.kluin@...il.com>
---
> Now you seem to make my previous math working :-)
> 
>>> (max) i = 64, (max) j = 14, (64+14+16)/2 = 47 < 69, so it seems to copy
>>> less than its size?
> 
> Jarek P.
> 

You're right, thanks for reviewing, this one should be correct.

diff --git a/drivers/net/eexpress.c b/drivers/net/eexpress.c
index 1686dca..1f016d6 100644
--- a/drivers/net/eexpress.c
+++ b/drivers/net/eexpress.c
@@ -1474,13 +1474,13 @@ static void eexp_hw_init586(struct net_device *dev)
 	outw(0x0000, ioaddr + 0x800c);
 	outw(0x0000, ioaddr + 0x800e);
 
-	for (i = 0; i < (sizeof(start_code)); i+=32) {
+	for (i = 0; i < ARRAY_SIZE(start_code) * 2; i+=32) {
 		int j;
 		outw(i, ioaddr + SM_PTR);
-		for (j = 0; j < 16; j+=2)
+		for (j = 0; j < 16 && (i+j)/2 < ARRAY_SIZE(start_code); j+=2)
 			outw(start_code[(i+j)/2],
 			     ioaddr+0x4000+j);
-		for (j = 0; j < 16; j+=2)
+		for (j = 0; j < 16 && (i+j+16)/2 < ARRAY_SIZE(start_code); j+=2)
 			outw(start_code[(i+j+16)/2],
 			     ioaddr+0x8000+j);
 	}
--
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