* [PATCH] mac80211: prevent out of bounds access in ieee80211_rx_h_action()
@ 2022-01-19 12:59 Dan Carpenter
2022-01-19 13:56 ` Johannes Berg
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2022-01-19 12:59 UTC (permalink / raw)
To: Johannes Berg; +Cc: John W. Linville, linux-wireless, kernel-janitors
Smatch complains that status->band comes from the skb->data so it
cannot be trusted. It's a u8 so it can be in the 0-255 range but the
rx->local->hw.wiphy->bands[] array only has 6 elements.
Fixes: 1d8d3dec5fbb ("mac80211: handle SMPS action frames")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
net/mac80211/rx.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 93680af62c47..9b0cf9e3b7bd 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3287,6 +3287,9 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
if (len < IEEE80211_MIN_ACTION_SIZE)
return RX_DROP_UNUSABLE;
+ if (status->band >= NUM_NL80211_BANDS)
+ goto invalid;
+
if (!rx->sta && mgmt->u.action.category != WLAN_CATEGORY_PUBLIC &&
mgmt->u.action.category != WLAN_CATEGORY_SELF_PROTECTED &&
mgmt->u.action.category != WLAN_CATEGORY_SPECTRUM_MGMT)
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] mac80211: prevent out of bounds access in ieee80211_rx_h_action()
2022-01-19 12:59 [PATCH] mac80211: prevent out of bounds access in ieee80211_rx_h_action() Dan Carpenter
@ 2022-01-19 13:56 ` Johannes Berg
2022-01-19 15:07 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Johannes Berg @ 2022-01-19 13:56 UTC (permalink / raw)
To: Dan Carpenter; +Cc: John W. Linville, linux-wireless, kernel-janitors
On Wed, 2022-01-19 at 15:59 +0300, Dan Carpenter wrote:
> Smatch complains that status->band comes from the skb->data
>
Hmm. How does it come to that conclusion? It's not really true? It comes
from skb->cb, and the driver should fill it. Also, we have:
void ieee80211_rx_list(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,
struct sk_buff *skb, struct list_head *list)
{
...
if (WARN_ON(status->band >= NUM_NL80211_BANDS))
goto drop;
so I really don't think this patch is needed?
johannes
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mac80211: prevent out of bounds access in ieee80211_rx_h_action()
2022-01-19 13:56 ` Johannes Berg
@ 2022-01-19 15:07 ` Dan Carpenter
2022-01-22 7:14 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2022-01-19 15:07 UTC (permalink / raw)
To: Johannes Berg; +Cc: John W. Linville, linux-wireless, kernel-janitors
On Wed, Jan 19, 2022 at 02:56:52PM +0100, Johannes Berg wrote:
> On Wed, 2022-01-19 at 15:59 +0300, Dan Carpenter wrote:
> > Smatch complains that status->band comes from the skb->data
> >
>
> Hmm. How does it come to that conclusion? It's not really true? It comes
> from skb->cb, and the driver should fill it.
Ugh... Sorry. I misread the code. I spent some time trying to figure
this out as well, but I still didn't figure it out.
So, yeah. It's skb->cb and Smatch for some reason thinks skb->cb holds
user data... I will look into this.
> Also, we have:
>
> void ieee80211_rx_list(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,
> struct sk_buff *skb, struct list_head *list)
> {
> ...
> if (WARN_ON(status->band >= NUM_NL80211_BANDS))
> goto drop;
>
>
> so I really don't think this patch is needed?
The problem with that is that ->cb is an array of char so Smatch doesn't
track status->band across function boundaries.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mac80211: prevent out of bounds access in ieee80211_rx_h_action()
2022-01-19 15:07 ` Dan Carpenter
@ 2022-01-22 7:14 ` Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2022-01-22 7:14 UTC (permalink / raw)
To: Johannes Berg; +Cc: John W. Linville, linux-wireless, kernel-janitors
On Wed, Jan 19, 2022 at 06:07:33PM +0300, Dan Carpenter wrote:
> So, yeah. It's skb->cb and Smatch for some reason thinks skb->cb holds
> user data... I will look into this.
I fixed this bug. I'll test the fix for a while before pushing it.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-01-22 7:15 UTC | newest]
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2022-01-19 12:59 [PATCH] mac80211: prevent out of bounds access in ieee80211_rx_h_action() Dan Carpenter
2022-01-19 13:56 ` Johannes Berg
2022-01-19 15:07 ` Dan Carpenter
2022-01-22 7:14 ` Dan Carpenter
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