diff mbox

rose_dev: fix memcpy-bug in rose_set_mac_address

Message ID 4F72D02F.6090907@iogearbox.net
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

danborkmann@iogearbox.net March 28, 2012, 8:47 a.m. UTC 
David Miller <davem@davemloft.net> wrote:

>> This patch fixes a small bug in rose_set_mac_address. If the current and new
>> MAC addresses match, then nothing needs to be done. However memcpy was used
>> instead of memcmp for comparison.
>>
>> The patch is against the latest net-tree.
>>
>> Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
>
> You're breaking this code, not fixing it.
>
> If you don't keep the memcpy, then the calls right below which setup
> the loopback node will use the previous device address not the new
> one being configured.

David, thanks for your feedback! So here's a small rework of the patch:

If both addresses equal, nothing needs to be done. If the device is down,
then we simply copy the new address to dev->dev_addr. If the device is up,
then we add another loopback device with the new address, and if that does
not fail, we remove the loopback device with the old address. And only
then, we update the dev->dev_addr.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
---
 net/rose/rose_dev.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

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Comments

David Miller April 1, 2012, 8:16 p.m. UTC | #1 
From: Daniel Borkmann <danborkmann@iogearbox.net>
Date: Wed, 28 Mar 2012 10:47:43 +0200

> If both addresses equal, nothing needs to be done. If the device is down,
> then we simply copy the new address to dev->dev_addr. If the device is up,
> then we add another loopback device with the new address, and if that does
> not fail, we remove the loopback device with the old address. And only
> then, we update the dev->dev_addr.
> 
> Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>

Applied and queued up for -stable.
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diff mbox

Patch

diff --git a/net/rose/rose_dev.c b/net/rose/rose_dev.c
index 178ff4f..2679507 100644
--- a/net/rose/rose_dev.c
+++ b/net/rose/rose_dev.c
@@ -96,11 +96,11 @@  static int rose_set_mac_address(struct net_device *dev, void *addr)
 	struct sockaddr *sa = addr;
 	int err;
 
-	if (!memcpy(dev->dev_addr, sa->sa_data, dev->addr_len))
+	if (!memcmp(dev->dev_addr, sa->sa_data, dev->addr_len))
 		return 0;
 
 	if (dev->flags & IFF_UP) {
-		err = rose_add_loopback_node((rose_address *)dev->dev_addr);
+		err = rose_add_loopback_node((rose_address *)sa->sa_data);
 		if (err)
 			return err;