2019-10-17 13:50:30

by Laura Abbott

Subject: [PATCH] rtlwifi: Fix potential overflow on P2P code

Nicolas Waisman noticed that even though noa_len is checked for
a compatible length it's still possible to overrun the buffers
of p2pinfo since there's no check on the upper bound of noa_num.
Bounds check noa_num against P2P_MAX_NOA_NUM.

Reported-by: Nicolas Waisman <[email protected]>
Signed-off-by: Laura Abbott <[email protected]>
---
Compile tested only as this was reported to the security list.
---
drivers/net/wireless/realtek/rtlwifi/ps.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtlwifi/ps.c b/drivers/net/wireless/realtek/rtlwifi/ps.c
index 70f04c2f5b17..c5cff598383d 100644
--- a/drivers/net/wireless/realtek/rtlwifi/ps.c
+++ b/drivers/net/wireless/realtek/rtlwifi/ps.c
@@ -754,6 +754,13 @@ static void rtl_p2p_noa_ie(struct ieee80211_hw *hw, void *data,
return;
} else {
noa_num = (noa_len - 2) / 13;
+ if (noa_num > P2P_MAX_NOA_NUM) {
+ RT_TRACE(rtlpriv, COMP_INIT, DBG_LOUD,
+ "P2P notice of absence: invalid noa_num.%d\n",
+ noa_num);
+ return;
+ }
+
}
noa_index = ie[3];
if (rtlpriv->psc.p2p_ps_info.p2p_ps_mode ==
@@ -848,6 +855,13 @@ static void rtl_p2p_action_ie(struct ieee80211_hw *hw, void *data,
return;
} else {
noa_num = (noa_len - 2) / 13;
+ if (noa_num > P2P_MAX_NOA_NUM) {
+ RT_TRACE(rtlpriv, COMP_FW, DBG_LOUD,
+ "P2P notice of absence: invalid noa_len.%d\n",
+ noa_len);
+ return;
+
+ }
}
noa_index = ie[3];
if (rtlpriv->psc.p2p_ps_info.p2p_ps_mode ==
--
2.21.0

2019-10-18 05:26:53

by Ping-Ke Shih

Subject: RE: [PATCH] rtlwifi: Fix potential overflow on P2P code

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf
> Of Laura Abbott
> Sent: Thursday, October 17, 2019 4:57 AM
> To: Pkshih; Kalle Valo
> Cc: Laura Abbott; David S. Miller; [email protected]; [email protected];
> [email protected]; Nicolas Waisman
> Subject: [PATCH] rtlwifi: Fix potential overflow on P2P code
>
> Nicolas Waisman noticed that even though noa_len is checked for
> a compatible length it's still possible to overrun the buffers
> of p2pinfo since there's no check on the upper bound of noa_num.
> Bounds check noa_num against P2P_MAX_NOA_NUM.
>
> Reported-by: Nicolas Waisman <[email protected]>
> Signed-off-by: Laura Abbott <[email protected]>
> ---
> Compile tested only as this was reported to the security list.
> ---
> drivers/net/wireless/realtek/rtlwifi/ps.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/net/wireless/realtek/rtlwifi/ps.c b/drivers/net/wireless/realtek/rtlwifi/ps.c
> index 70f04c2f5b17..c5cff598383d 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/ps.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/ps.c
> @@ -754,6 +754,13 @@ static void rtl_p2p_noa_ie(struct ieee80211_hw *hw, void *data,
> return;
> } else {
> noa_num = (noa_len - 2) / 13;
> + if (noa_num > P2P_MAX_NOA_NUM) {
> + RT_TRACE(rtlpriv, COMP_INIT, DBG_LOUD,
> + "P2P notice of absence: invalid noa_num.%d\n",
> + noa_num);
> + return;

As the discussion at <[email protected]>, I think it'd be better to use
the min between noa_num and P2P_MAX_NOA_NUM, and fall through the code instead
of return. Because ignore all NoA isn't better than apply two of them.


> + }
> +
> }
> noa_index = ie[3];
> if (rtlpriv->psc.p2p_ps_info.p2p_ps_mode ==
> @@ -848,6 +855,13 @@ static void rtl_p2p_action_ie(struct ieee80211_hw *hw, void *data,
> return;
> } else {
> noa_num = (noa_len - 2) / 13;
> + if (noa_num > P2P_MAX_NOA_NUM) {
> + RT_TRACE(rtlpriv, COMP_FW, DBG_LOUD,
> + "P2P notice of absence: invalid noa_len.%d\n",
> + noa_len);
> + return;
> +
> + }
> }
> noa_index = ie[3];
> if (rtlpriv->psc.p2p_ps_info.p2p_ps_mode ==
> --
> 2.21.0