[patch 2/9] ath9k: range checking issues in htc_hst.c

[patch 2/9] ath9k: range checking issues in htc_hst.c

[Dan Carpenter]

The original code had ENDPOINT_MAX and HST_ENDPOINT_MAX switched.

Also the first loop was off by one, it started past the end of the array
and went down to 1 instead of going down to 0.  The test at the end of
the loop to see if we exited via a break wasn't right because
"tmp_endpoint" is always non-null here.

Signed-off-by: Dan Carpenter <error27@gmail.com>

diff --git a/drivers/net/wireless/ath/ath9k/htc_hst.c b/drivers/net/wireless/ath/ath9k/htc_hst.c
index 7bf6ce1..0c062d0 100644
--- a/drivers/net/wireless/ath/ath9k/htc_hst.c
+++ b/drivers/net/wireless/ath/ath9k/htc_hst.c
@@ -116,7 +116,7 @@ static void htc_process_conn_rsp(struct htc_target *target,
 		max_msglen = be16_to_cpu(svc_rspmsg->max_msg_len);
 		endpoint = &target->endpoint[epid];
 
-		for (tepid = ENDPOINT_MAX; tepid > ENDPOINT0; tepid--) {
+		for (tepid = HST_ENDPOINT_MAX - 1; tepid >= ENDPOINT0; tepid--) {
 			tmp_endpoint = &target->endpoint[tepid];
 			if (tmp_endpoint->service_id == service_id) {
 				tmp_endpoint->service_id = 0;
@@ -124,7 +124,7 @@ static void htc_process_conn_rsp(struct htc_target *target,
 			}
 		}
 
-		if (!tmp_endpoint)
+		if (tepid < ENDPOINT0)
 			return;
 
 		endpoint->service_id = service_id;
@@ -297,7 +297,7 @@ void htc_stop(struct htc_target *target)
 	enum htc_endpoint_id epid;
 	struct htc_endpoint *endpoint;
 
-	for (epid = ENDPOINT0; epid <= ENDPOINT_MAX; epid++) {
+	for (epid = ENDPOINT0; epid < HST_ENDPOINT_MAX; epid++) {
 		endpoint = &target->endpoint[epid];
 		if (endpoint->service_id != 0)
 			target->hif->stop(target->hif_dev, endpoint->ul_pipeid);
@@ -309,7 +309,7 @@ void htc_start(struct htc_target *target)
 	enum htc_endpoint_id epid;
 	struct htc_endpoint *endpoint;
 
-	for (epid = ENDPOINT0; epid <= ENDPOINT_MAX; epid++) {
+	for (epid = ENDPOINT0; epid < HST_ENDPOINT_MAX; epid++) {
 		endpoint = &target->endpoint[epid];
 		if (endpoint->service_id != 0)
 			target->hif->start(target->hif_dev,
@@ -377,7 +377,7 @@ void ath9k_htc_rx_msg(struct htc_target *htc_handle,
 	htc_hdr = (struct htc_frame_hdr *) skb->data;
 	epid = htc_hdr->endpoint_id;
 
-	if (epid >= ENDPOINT_MAX) {
+	if (epid >= HST_ENDPOINT_MAX) {
 		if (pipe_id != USB_REG_IN_PIPE)
 			dev_kfree_skb_any(skb);
 		else

[patch 2/9] ath9k: range checking issues in htc_hst.c

[Sujith]

Dan Carpenter wrote:
> The original code had ENDPOINT_MAX and HST_ENDPOINT_MAX switched.

Hm, no.

> Also the first loop was off by one, it started past the end of the array
> and went down to 1 instead of going down to 0.  The test at the end of
> the loop to see if we exited via a break wasn't right because
> "tmp_endpoint" is always non-null here.
> 
> Signed-off-by: Dan Carpenter <error27@gmail.com>
> 
> diff --git a/drivers/net/wireless/ath/ath9k/htc_hst.c b/drivers/net/wireless/ath/ath9k/htc_hst.c
> index 7bf6ce1..0c062d0 100644
> --- a/drivers/net/wireless/ath/ath9k/htc_hst.c
> +++ b/drivers/net/wireless/ath/ath9k/htc_hst.c
> @@ -116,7 +116,7 @@ static void htc_process_conn_rsp(struct htc_target *target,
>  		max_msglen = be16_to_cpu(svc_rspmsg->max_msg_len);
>  		endpoint = &target->endpoint[epid];
>  
> -		for (tepid = ENDPOINT_MAX; tepid > ENDPOINT0; tepid--) {
> +		for (tepid = HST_ENDPOINT_MAX - 1; tepid >= ENDPOINT0; tepid--) {

This should be (tepid = (ENDPOINT_MAX - 1); tepid > ENDPOINT0; tepid--),
and the NULL check below can be retained.

This is because ENDPOINT0 is reserved.

>  			tmp_endpoint = &target->endpoint[tepid];
>  			if (tmp_endpoint->service_id == service_id) {
>  				tmp_endpoint->service_id = 0;
> @@ -124,7 +124,7 @@ static void htc_process_conn_rsp(struct htc_target *target,
>  			}
>  		}
>  
> -		if (!tmp_endpoint)
> +		if (tepid < ENDPOINT0)
>  			return;
>  
>  		endpoint->service_id = service_id;
> @@ -297,7 +297,7 @@ void htc_stop(struct htc_target *target)
>  	enum htc_endpoint_id epid;
>  	struct htc_endpoint *endpoint;
>  
> -	for (epid = ENDPOINT0; epid <= ENDPOINT_MAX; epid++) {
> +	for (epid = ENDPOINT0; epid < HST_ENDPOINT_MAX; epid++) {

ENDPOINT_MAX should be used here, but '<=' should be replaced by '<'.

>  		endpoint = &target->endpoint[epid];
>  		if (endpoint->service_id != 0)
>  			target->hif->stop(target->hif_dev, endpoint->ul_pipeid);
> @@ -309,7 +309,7 @@ void htc_start(struct htc_target *target)
>  	enum htc_endpoint_id epid;
>  	struct htc_endpoint *endpoint;
>  
> -	for (epid = ENDPOINT0; epid <= ENDPOINT_MAX; epid++) {
> +	for (epid = ENDPOINT0; epid < HST_ENDPOINT_MAX; epid++) {
>  		endpoint = &target->endpoint[epid];

Same as above.

>  		if (endpoint->service_id != 0)
>  			target->hif->start(target->hif_dev,
> @@ -377,7 +377,7 @@ void ath9k_htc_rx_msg(struct htc_target *htc_handle,
>  	htc_hdr = (struct htc_frame_hdr *) skb->data;
>  	epid = htc_hdr->endpoint_id;
>  
> -	if (epid >= ENDPOINT_MAX) {
> +	if (epid >= HST_ENDPOINT_MAX) {
>  		if (pipe_id != USB_REG_IN_PIPE)
>  			dev_kfree_skb_any(skb);
>  		else

The original check was correct ...

Sujith

Re: [patch 2/9] ath9k: range checking issues in htc_hst.c

[Dan Carpenter]

On Mon, May 10, 2010 at 10:07:12AM +0530, Sujith wrote:
> Dan Carpenter wrote:
> > The original code had ENDPOINT_MAX and HST_ENDPOINT_MAX switched.
> 
> Hm, no.
> 

I'm afraid I don't understand.  ENDPOINT_MAX is 22 and HST_ENDPOINT_MAX
is 8.  The htc_target struct is defined as having 8 endpoints.

drivers/net/wireless/ath/ath9k/htc_hst.h
   137  struct htc_target {
   138          void *hif_dev;
   139          struct ath9k_htc_priv *drv_priv;
   140          struct device *dev;
   141          struct ath9k_htc_hif *hif;
   142          struct htc_endpoint endpoint[HST_ENDPOINT_MAX];
                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^

So in the original code:
drivers/net/wireless/ath/ath9k/htc_hst.c
   119                  for (tepid = ENDPOINT_MAX; tepid > ENDPOINT0; tepid--) {
   120                          tmp_endpoint = &target->endpoint[tepid];
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^

	We are past the end of the array here.  22 vs 7.

Perhaps the htc_target struct should be changed to ENDPOINT_MAX?

regards,
dan carpenter

Re: [patch 2/9] ath9k: range checking issues in htc_hst.c

[Sujith]

Dan Carpenter wrote:
> I'm afraid I don't understand.  ENDPOINT_MAX is 22 and HST_ENDPOINT_MAX
> is 8.  The htc_target struct is defined as having 8 endpoints.
> 
> drivers/net/wireless/ath/ath9k/htc_hst.h
>    137  struct htc_target {
>    138          void *hif_dev;
>    139          struct ath9k_htc_priv *drv_priv;
>    140          struct device *dev;
>    141          struct ath9k_htc_hif *hif;
>    142          struct htc_endpoint endpoint[HST_ENDPOINT_MAX];
>                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> So in the original code:
> drivers/net/wireless/ath/ath9k/htc_hst.c
>    119                  for (tepid = ENDPOINT_MAX; tepid > ENDPOINT0; tepid--) {
>    120                          tmp_endpoint = &target->endpoint[tepid];
>                                                ^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> 	We are past the end of the array here.  22 vs 7.
> 
> Perhaps the htc_target struct should be changed to ENDPOINT_MAX?

Ah right. That should be fixed.

Sujith

Re: [ath9k-devel] [patch 2/9] ath9k: range checking issues in htc_hst.c

[Pavel Roskin]

On Mon, 2010-05-10 at 16:20 +0530, Sujith wrote:

> Ah right. That should be fixed.

I suggest using ARRAY_SIZE(target->endpoint) to be sure.

-- 
Regards,
Pavel Roskin

[patch 2/9] ath9k: range checking issues in htc_hst.c

[Sujith.Manoharan]

Dan Carpenter wrote:
> The original code had ENDPOINT_MAX and HST_ENDPOINT_MAX switched.
> 
> Also the first loop was off by one, it started past the end of the array
> and went down to 1 instead of going down to 0.  The test at the end of
> the loop to see if we exited via a break wasn't right because
> "tmp_endpoint" is always non-null here.

This is a very good catch and fixes a stack corruption issue.
Do you mind if I work upon this patch and send out an updated fix ?

Sujith

Re: [patch 2/9] ath9k: range checking issues in htc_hst.c

[Dan Carpenter]

On Tue, May 11, 2010 at 11:20:02AM +0530, Sujith.Manoharan@atheros.com wrote:
> Dan Carpenter wrote:
> > The original code had ENDPOINT_MAX and HST_ENDPOINT_MAX switched.
> > 
> > Also the first loop was off by one, it started past the end of the array
> > and went down to 1 instead of going down to 0.  The test at the end of
> > the loop to see if we exited via a break wasn't right because
> > "tmp_endpoint" is always non-null here.
> 
> This is a very good catch and fixes a stack corruption issue.
> Do you mind if I work upon this patch and send out an updated fix ?
> 
> Sujith

Sorry, I meant to do that yesterday but I was out of it.  Yes.  Please 
send the updated fix.

regards,
dan carpenter