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[v2] wifi: mac80211_hwsim: drop short frames

Message ID 20230815212800.d849938fdc9f.I1efbeef082c3f7094037882f213202d760848eb7@changeid (mailing list archive)
State Accepted
Delegated to: Johannes Berg
Headers show
Series [v2] wifi: mac80211_hwsim: drop short frames | expand

Commit Message

Johannes Berg Aug. 15, 2023, 7:28 p.m. UTC 
From: Johannes Berg <johannes.berg@intel.com>

While technically some control frames like ACK are shorter and
end after Address 1, such frames shouldn't be forwarded through
wmediumd or similar userspace, so require the full 3-address
header to avoid accessing invalid memory if shorter frames are
passed in.

Reported-by: syzbot+b2645b5bf1512b81fa22@syzkaller.appspotmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/virtual/mac80211_hwsim.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Jeff Johnson Aug. 15, 2023, 10:30 p.m. UTC | #1 
On 8/15/2023 12:28 PM, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@intel.com>
> 
> While technically some control frames like ACK are shorter and
> end after Address 1, such frames shouldn't be forwarded through
> wmediumd or similar userspace, so require the full 3-address
> header to avoid accessing invalid memory if shorter frames are
> passed in.
> 
> Reported-by: syzbot+b2645b5bf1512b81fa22@syzkaller.appspotmail.com
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>

> ---
>   drivers/net/wireless/virtual/mac80211_hwsim.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/wireless/virtual/mac80211_hwsim.c b/drivers/net/wireless/virtual/mac80211_hwsim.c
> index f446fd0e8cd0..dd516cec4197 100644
> --- a/drivers/net/wireless/virtual/mac80211_hwsim.c
> +++ b/drivers/net/wireless/virtual/mac80211_hwsim.c
> @@ -5626,14 +5626,15 @@ static int hwsim_cloned_frame_received_nl(struct sk_buff *skb_2,
>   	frame_data_len = nla_len(info->attrs[HWSIM_ATTR_FRAME]);
>   	frame_data = (void *)nla_data(info->attrs[HWSIM_ATTR_FRAME]);
>   
> +	if (frame_data_len < sizeof(struct ieee80211_hdr_3addr) ||
> +	    frame_data_len > IEEE80211_MAX_DATA_LEN)
> +		goto err;
> +
>   	/* Allocate new skb here */
>   	skb = alloc_skb(frame_data_len, GFP_KERNEL);
>   	if (skb == NULL)
>   		goto err;
>   
> -	if (frame_data_len > IEEE80211_MAX_DATA_LEN)
> -		goto err;
> -
>   	/* Copy the data */
>   	skb_put_data(skb, frame_data, frame_data_len);
>
diff mbox series

Patch

diff --git a/drivers/net/wireless/virtual/mac80211_hwsim.c b/drivers/net/wireless/virtual/mac80211_hwsim.c
index f446fd0e8cd0..dd516cec4197 100644
--- a/drivers/net/wireless/virtual/mac80211_hwsim.c
+++ b/drivers/net/wireless/virtual/mac80211_hwsim.c
@@ -5626,14 +5626,15 @@  static int hwsim_cloned_frame_received_nl(struct sk_buff *skb_2,
 	frame_data_len = nla_len(info->attrs[HWSIM_ATTR_FRAME]);
 	frame_data = (void *)nla_data(info->attrs[HWSIM_ATTR_FRAME]);
 
+	if (frame_data_len < sizeof(struct ieee80211_hdr_3addr) ||
+	    frame_data_len > IEEE80211_MAX_DATA_LEN)
+		goto err;
+
 	/* Allocate new skb here */
 	skb = alloc_skb(frame_data_len, GFP_KERNEL);
 	if (skb == NULL)
 		goto err;
 
-	if (frame_data_len > IEEE80211_MAX_DATA_LEN)
-		goto err;
-
 	/* Copy the data */
 	skb_put_data(skb, frame_data, frame_data_len);