2020-09-06 21:27:27

by Tom Rix

Subject: [PATCH] ath11k: fix a double free and a memory leak

From: Tom Rix <[email protected]>

clang static analyzer reports this problem

mac.c:6204:2: warning: Attempt to free released memory
kfree(ar->mac.sbands[NL80211_BAND_2GHZ].channels);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The channels pointer is allocated in ath11k_mac_setup_channels_rates()
When it fails midway, it cleans up the memory it has already allocated.
So the error handling needs to skip freeing the memory.

There is a second problem.
ath11k_mac_setup_channels_rates(), allocates 3 channels. err_free
misses releasing ar->mac.sbands[NL80211_BAND_6GHZ].channels

Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Signed-off-by: Tom Rix <[email protected]>
---
drivers/net/wireless/ath/ath11k/mac.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index f4a085baff38..f1a964b01a83 100644
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -6089,7 +6089,7 @@ static int __ath11k_mac_register(struct ath11k *ar)
ret = ath11k_mac_setup_channels_rates(ar,
cap->supported_bands);
if (ret)
- goto err_free;
+ goto err;

ath11k_mac_setup_ht_vht_cap(ar, cap, &ht_cap);
ath11k_mac_setup_he_cap(ar, cap);
@@ -6203,7 +6203,8 @@ static int __ath11k_mac_register(struct ath11k *ar)
err_free:
kfree(ar->mac.sbands[NL80211_BAND_2GHZ].channels);
kfree(ar->mac.sbands[NL80211_BAND_5GHZ].channels);
-
+ kfree(ar->mac.sbands[NL80211_BAND_6GHZ].channels);
+err:
SET_IEEE80211_DEV(ar->hw, NULL);
return ret;
}
--
2.18.1

2020-09-08 04:27:03

by Nathan Chancellor

Subject: Re: [PATCH] ath11k: fix a double free and a memory leak

On Sun, Sep 06, 2020 at 02:26:25PM -0700, [email protected] wrote:
> From: Tom Rix <[email protected]>
>
> clang static analyzer reports this problem
>
> mac.c:6204:2: warning: Attempt to free released memory
> kfree(ar->mac.sbands[NL80211_BAND_2GHZ].channels);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> The channels pointer is allocated in ath11k_mac_setup_channels_rates()
> When it fails midway, it cleans up the memory it has already allocated.
> So the error handling needs to skip freeing the memory.
>
> There is a second problem.
> ath11k_mac_setup_channels_rates(), allocates 3 channels. err_free
> misses releasing ar->mac.sbands[NL80211_BAND_6GHZ].channels
>
> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
> Signed-off-by: Tom Rix <[email protected]>

Reviewed-by: Nathan Chancellor <[email protected]>

> ---
> drivers/net/wireless/ath/ath11k/mac.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
> index f4a085baff38..f1a964b01a83 100644
> --- a/drivers/net/wireless/ath/ath11k/mac.c
> +++ b/drivers/net/wireless/ath/ath11k/mac.c
> @@ -6089,7 +6089,7 @@ static int __ath11k_mac_register(struct ath11k *ar)
> ret = ath11k_mac_setup_channels_rates(ar,
> cap->supported_bands);
> if (ret)
> - goto err_free;
> + goto err;
>
> ath11k_mac_setup_ht_vht_cap(ar, cap, &ht_cap);
> ath11k_mac_setup_he_cap(ar, cap);
> @@ -6203,7 +6203,8 @@ static int __ath11k_mac_register(struct ath11k *ar)
> err_free:
> kfree(ar->mac.sbands[NL80211_BAND_2GHZ].channels);
> kfree(ar->mac.sbands[NL80211_BAND_5GHZ].channels);
> -
> + kfree(ar->mac.sbands[NL80211_BAND_6GHZ].channels);
> +err:
> SET_IEEE80211_DEV(ar->hw, NULL);
> return ret;
> }
> --
> 2.18.1
>