[patch] IB/iser: use after free in iser_snd_completion()

[patch] IB/iser: use after free in iser_snd_completion()

[Dan Carpenter]

We use "tx_desc" again after we free it.

Signed-off-by: Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>

diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
index 538822684d5b..334f34b1cd46 100644
--- a/drivers/infiniband/ulp/iser/iser_initiator.c
+++ b/drivers/infiniband/ulp/iser/iser_initiator.c
@@ -610,11 +610,12 @@ void iser_snd_completion(struct iser_tx_desc *tx_desc,
 		ib_dma_unmap_single(device->ib_device, tx_desc->dma_addr,
 					ISER_HEADERS_LEN, DMA_TO_DEVICE);
 		kmem_cache_free(ig.desc_cache, tx_desc);
+		tx_desc = NULL;
 	}
 
 	atomic_dec(&ib_conn->post_send_buf_count);
 
-	if (tx_desc->type == ISCSI_TX_CONTROL) {
+	if (tx_desc && tx_desc->type == ISCSI_TX_CONTROL) {
 		/* this arithmetic is legal by libiscsi dd_data allocation */
 		task = (void *) ((long)(void *)tx_desc -
 				  sizeof(struct iscsi_task));
--
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Re: [patch] IB/iser: use after free in iser_snd_completion()

[Or Gerlitz]

On Wed, Jan 29, 2014, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> We use "tx_desc" again after we free it.

yep, this is legacy code which isn't much of use over the last years
and hence the bug went in unnoticed


> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
> index 538822684d5b..334f34b1cd46 100644
> --- a/drivers/infiniband/ulp/iser/iser_initiator.c
> +++ b/drivers/infiniband/ulp/iser/iser_initiator.c
> @@ -610,11 +610,12 @@ void iser_snd_completion(struct iser_tx_desc *tx_desc,
>                 ib_dma_unmap_single(device->ib_device, tx_desc->dma_addr,
>                                         ISER_HEADERS_LEN, DMA_TO_DEVICE);
>                 kmem_cache_free(ig.desc_cache, tx_desc);
> +               tx_desc = NULL;
>         }
>
>         atomic_dec(&ib_conn->post_send_buf_count);
>
> -       if (tx_desc->type == ISCSI_TX_CONTROL) {
> +       if (tx_desc && tx_desc->type == ISCSI_TX_CONTROL) {
>                 /* this arithmetic is legal by libiscsi dd_data allocation */
>                 task = (void *) ((long)(void *)tx_desc -
>                                   sizeof(struct iscsi_task));
> --
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> the body of a message to majordomo@vger.kernel.org
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Re: [patch] IB/iser: use after free in iser_snd_completion()

[Or Gerlitz]

On Thu, Jan 30, 2014 at 11:04 PM, Or Gerlitz <or.gerlitz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Wed, Jan 29, 2014, Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
>> We use "tx_desc" again after we free it.
>
> yep, this is legacy code which isn't much of use over the last years
> and hence the bug went in unnoticed

Acked-by: Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
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