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wifi: ath9k: protect WMI command response buffer replacement with a lock

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[ Upstream commit 454994cfa9e4c18b6df9f78b60db8eadc20a6c25 ]

If ath9k_wmi_cmd() has exited with a timeout, it is possible that during
next ath9k_wmi_cmd() call the wmi_rsp callback for previous wmi command
writes to new wmi->cmd_rsp_buf and makes a completion. This results in an
invalid ath9k_wmi_cmd() return value.

Move the replacement of WMI command response buffer and length under
wmi_lock. Note that last_seq_id value is updated there, too.

Thus, the buffer cannot be written to by a belated wmi_rsp callback
because that path is properly rejected by the last_seq_id check.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230425192607.18015-2-pchelkin@ispras.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Fedor Pchelkin 2023-04-25 22:26:07 +03:00 committed by Greg Kroah-Hartman
parent 6904c7afd5
commit 11f93fff6e
1 changed files with 8 additions and 6 deletions
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14
drivers/net/wireless/ath/ath9k/wmi.c
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@ -283,7 +283,8 @@ int ath9k_wmi_connect(struct htc_target *htc, struct wmi *wmi,
static int ath9k_wmi_cmd_issue(struct wmi *wmi,
struct sk_buff *skb,
enum wmi_cmd_id cmd, u16 len)
enum wmi_cmd_id cmd, u16 len,
u8 *rsp_buf, u32 rsp_len)
{
struct wmi_cmd_hdr *hdr;
unsigned long flags;
@ -293,6 +294,11 @@ static int ath9k_wmi_cmd_issue(struct wmi *wmi,
hdr->seq_no = cpu_to_be16(++wmi->tx_seq_id);
spin_lock_irqsave(&wmi->wmi_lock, flags);
/* record the rsp buffer and length */
wmi->cmd_rsp_buf = rsp_buf;
wmi->cmd_rsp_len = rsp_len;
wmi->last_seq_id = wmi->tx_seq_id;
spin_unlock_irqrestore(&wmi->wmi_lock, flags);
@ -333,11 +339,7 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
goto out;
}
/* record the rsp buffer and length */
wmi->cmd_rsp_buf = rsp_buf;
wmi->cmd_rsp_len = rsp_len;
ret = ath9k_wmi_cmd_issue(wmi, skb, cmd_id, cmd_len);
ret = ath9k_wmi_cmd_issue(wmi, skb, cmd_id, cmd_len, rsp_buf, rsp_len);
if (ret)
goto out;