[PATCH] ath6kl: wmi: prevent a shift wrapping bug in ath6kl_wmi_delete_pstream_cmd()

* [PATCH] ath6kl: wmi: prevent a shift wrapping bug in ath6kl_wmi_delete_pstream_cmd()
@ 2020-09-18 14:27 Dan Carpenter
  2020-09-22  7:46 ` Kalle Valo
  0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2020-09-18 14:27 UTC (permalink / raw)
  To: Kalle Valo; +Cc: Jakub Kicinski, linux-wireless, kernel-janitors

The "tsid" is a user controlled u8 which comes from debugfs.  Values
more than 15 are invalid because "active_tsids" is a 16 bit variable.
If the value of "tsid" is more than 31 then that leads to a shift
wrapping bug.

Fixes: 8fffd9e5ec9e ("ath6kl: Implement support for QOS-enable and QOS-disable from userspace")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
In the current code if the TSID bit isn't set it returns -ENODATA but
returning -EINVAL here should be fine.

 drivers/net/wireless/ath/ath6kl/wmi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/wireless/ath/ath6kl/wmi.c b/drivers/net/wireless/ath/ath6kl/wmi.c
index a4339cca661f..dbc47702a268 100644
--- a/drivers/net/wireless/ath/ath6kl/wmi.c
+++ b/drivers/net/wireless/ath/ath6kl/wmi.c
@@ -2639,6 +2639,11 @@ int ath6kl_wmi_delete_pstream_cmd(struct wmi *wmi, u8 if_idx, u8 traffic_class,
 		return -EINVAL;
 	}
 
+	if (tsid >= 16) {
+		ath6kl_err("invalid tsid: %d\n", tsid);
+		return -EINVAL;
+	}
+
 	skb = ath6kl_wmi_get_new_buf(sizeof(*cmd));
 	if (!skb)
 		return -ENOMEM;
-- 
2.28.0

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