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* [PATCH] rsi: Fix NULL pointer dereference in kmalloc
@ 2019-03-02 20:31 Aditya Pakki
  2019-03-03  3:02 ` Joe Perches
  2019-03-03 14:14 ` Johannes Berg
  0 siblings, 2 replies; 3+ messages in thread
From: Aditya Pakki @ 2019-03-02 20:31 UTC (permalink / raw)
  To: pakki001
  Cc: kjlu, Amitkumar Karwar, Siva Rebbagondla, Kalle Valo,
	David S. Miller, linux-wireless, netdev, linux-kernel

kmalloc can fail in rsi_register_rates_channels but memcpy still attempts
to write to channels. The patch checks and avoids such a situation.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
---
 drivers/net/wireless/rsi/rsi_91x_mac80211.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/wireless/rsi/rsi_91x_mac80211.c b/drivers/net/wireless/rsi/rsi_91x_mac80211.c
index e56fc83faf0e..59eb1f533d0e 100644
--- a/drivers/net/wireless/rsi/rsi_91x_mac80211.c
+++ b/drivers/net/wireless/rsi/rsi_91x_mac80211.c
@@ -197,6 +197,11 @@ static void rsi_register_rates_channels(struct rsi_hw *adapter, int band)
 
 	if (band == NL80211_BAND_2GHZ) {
 		channels = kmalloc(sizeof(rsi_2ghz_channels), GFP_KERNEL);
+		if (!channels) {
+			rsi_dbg(ERR_ZONE, "Failed to allocate memory\n");
+			return;
+		}
+
 		memcpy(channels,
 		       rsi_2ghz_channels,
 		       sizeof(rsi_2ghz_channels));
@@ -206,6 +211,11 @@ static void rsi_register_rates_channels(struct rsi_hw *adapter, int band)
 		sbands->n_bitrates = ARRAY_SIZE(rsi_rates);
 	} else {
 		channels = kmalloc(sizeof(rsi_5ghz_channels), GFP_KERNEL);
+		if (!channels) {
+			rsi_dbg(ERR_ZONE, "Failed to allocate memory\n");
+			return;
+		}
+
 		memcpy(channels,
 		       rsi_5ghz_channels,
 		       sizeof(rsi_5ghz_channels));
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] rsi: Fix NULL pointer dereference in kmalloc
  2019-03-02 20:31 [PATCH] rsi: Fix NULL pointer dereference in kmalloc Aditya Pakki
@ 2019-03-03  3:02 ` Joe Perches
  2019-03-03 14:14 ` Johannes Berg
  1 sibling, 0 replies; 3+ messages in thread
From: Joe Perches @ 2019-03-03  3:02 UTC (permalink / raw)
  To: Aditya Pakki
  Cc: kjlu, Amitkumar Karwar, Siva Rebbagondla, Kalle Valo,
	David S. Miller, linux-wireless, netdev, linux-kernel

On Sat, 2019-03-02 at 14:31 -0600, Aditya Pakki wrote:
> kmalloc can fail in rsi_register_rates_channels but memcpy still attempts
> to write to channels. The patch checks and avoids such a situation.
[]
> diff --git a/drivers/net/wireless/rsi/rsi_91x_mac80211.c b/drivers/net/wireless/rsi/rsi_91x_mac80211.c
[]
> @@ -197,6 +197,11 @@ static void rsi_register_rates_channels(struct rsi_hw *adapter, int band)

It'd be better to make this return -ENOMEM on failure
and test in the caller and push the failure up-stack.

>  
>  	if (band == NL80211_BAND_2GHZ) {
>  		channels = kmalloc(sizeof(rsi_2ghz_channels), GFP_KERNEL);
> +		if (!channels) {
> +			rsi_dbg(ERR_ZONE, "Failed to allocate memory\n");

Allocation error messages aren't really useful
as there's a generic OOM message.

> +			return;
> +		}
> +
>  		memcpy(channels,
>  		       rsi_2ghz_channels,
>  		       sizeof(rsi_2ghz_channels));
> @@ -206,6 +211,11 @@ static void rsi_register_rates_channels(struct rsi_hw *adapter, int band)
>  		sbands->n_bitrates = ARRAY_SIZE(rsi_rates);
>  	} else {
>  		channels = kmalloc(sizeof(rsi_5ghz_channels), GFP_KERNEL);
> +		if (!channels) {
> +			rsi_dbg(ERR_ZONE, "Failed to allocate memory\n");
> +			return;
> +		}
> +
>  		memcpy(channels,
>  		       rsi_5ghz_channels,
>  		       sizeof(rsi_5ghz_channels));


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] rsi: Fix NULL pointer dereference in kmalloc
  2019-03-02 20:31 [PATCH] rsi: Fix NULL pointer dereference in kmalloc Aditya Pakki
  2019-03-03  3:02 ` Joe Perches
@ 2019-03-03 14:14 ` Johannes Berg
  1 sibling, 0 replies; 3+ messages in thread
From: Johannes Berg @ 2019-03-03 14:14 UTC (permalink / raw)
  To: Aditya Pakki
  Cc: kjlu, Amitkumar Karwar, Siva Rebbagondla, Kalle Valo,
	David S. Miller, linux-wireless, netdev, linux-kernel

On Sat, 2019-03-02 at 14:31 -0600, Aditya Pakki wrote:
> kmalloc can fail in rsi_register_rates_channels but memcpy still attempts
> to write to channels. The patch checks and avoids such a situation.
> 
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> ---
>  drivers/net/wireless/rsi/rsi_91x_mac80211.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/net/wireless/rsi/rsi_91x_mac80211.c b/drivers/net/wireless/rsi/rsi_91x_mac80211.c
> index e56fc83faf0e..59eb1f533d0e 100644
> --- a/drivers/net/wireless/rsi/rsi_91x_mac80211.c
> +++ b/drivers/net/wireless/rsi/rsi_91x_mac80211.c
> @@ -197,6 +197,11 @@ static void rsi_register_rates_channels(struct rsi_hw *adapter, int band)
>  
>  	if (band == NL80211_BAND_2GHZ) {
>  		channels = kmalloc(sizeof(rsi_2ghz_channels), GFP_KERNEL);
> +		if (!channels) {
> +			rsi_dbg(ERR_ZONE, "Failed to allocate memory\n");
> +			return;
> +		}
> +
>  		memcpy(channels,
>  		       rsi_2ghz_channels,
>  		       sizeof(rsi_2ghz_channels));

Should probably be kmemdup() anyway though.

johannes


^ permalink raw reply	[flat|nested] 3+ messages in thread

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2019-03-02 20:31 [PATCH] rsi: Fix NULL pointer dereference in kmalloc Aditya Pakki
2019-03-03  3:02 ` Joe Perches
2019-03-03 14:14 ` Johannes Berg

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