2023-05-10 03:21:28

by Takashi Sakamoto

Subject: [PATCH] firewire: net: fix unexpected release of object for asynchronous request packet

The lifetime of object for asynchronous request packet is now maintained
by reference counting, while current implementation of firewire-net
releases the passed object in the handler.

This commit fixes the bug.

Reported-by: Dan Carpenter <[email protected]>
Link: https://lore.kernel.org/lkml/Y%2Fymx6WZIAlrtjLc@workstation/
Fixes: 13a55d6bb15f ("firewire: core: use kref structure to maintain lifetime of data for fw_request structure")
Signed-off-by: Takashi Sakamoto <[email protected]>
---
drivers/firewire/net.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c
index af22be84034b..538bd677c254 100644
--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -706,21 +706,22 @@ static void fwnet_receive_packet(struct fw_card *card, struct fw_request *r,
int rcode;

if (destination == IEEE1394_ALL_NODES) {
- kfree(r);
-
- return;
- }
-
- if (offset != dev->handler.offset)
+ // Although the response to the broadcast packet is not necessarily required, the
+ // fw_send_response() function should still be called to maintain the reference
+ // counting of the object. In the case, the call of function just releases the
+ // object as a result to decrease the reference counting.
+ rcode = RCODE_COMPLETE;
+ } else if (offset != dev->handler.offset) {
rcode = RCODE_ADDRESS_ERROR;
- else if (tcode != TCODE_WRITE_BLOCK_REQUEST)
+ } else if (tcode != TCODE_WRITE_BLOCK_REQUEST) {
rcode = RCODE_TYPE_ERROR;
- else if (fwnet_incoming_packet(dev, payload, length,
- source, generation, false) != 0) {
+ } else if (fwnet_incoming_packet(dev, payload, length,
+ source, generation, false) != 0) {
dev_err(&dev->netdev->dev, "incoming packet failure\n");
rcode = RCODE_CONFLICT_ERROR;
- } else
+ } else {
rcode = RCODE_COMPLETE;
+ }

fw_send_response(card, r, rcode);
}
--
2.37.2

2023-05-11 00:39:57

by Takashi Sakamoto

Subject: Re: [PATCH] firewire: net: fix unexpected release of object for asynchronous request packet

On Wed, May 10, 2023 at 12:12:05PM +0900, Takashi Sakamoto wrote:
> The lifetime of object for asynchronous request packet is now maintained
> by reference counting, while current implementation of firewire-net
> releases the passed object in the handler.
>
> This commit fixes the bug.
>
> Reported-by: Dan Carpenter <[email protected]>
> Link: https://lore.kernel.org/lkml/Y%2Fymx6WZIAlrtjLc@workstation/
> Fixes: 13a55d6bb15f ("firewire: core: use kref structure to maintain lifetime of data for fw_request structure")
> Signed-off-by: Takashi Sakamoto <[email protected]>
> ---
> drivers/firewire/net.c | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)

The patch is applied to for-linus branch and will be sent to mainline
within a few days.


Regards

Takashi Sakamoto