[PATCH 4.9 098/125] wil6210: fix length check in __wmi_send

From: Greg Kroah-Hartman
Date: Wed Apr 22 2020 - 06:55:15 EST


From: Lior David <qca_liord@xxxxxxxxxxxxxxxx>

[ Upstream commit 26a6d5274865532502c682ff378ac8ebe2886238 ]

The current length check:
sizeof(cmd) + len > r->entry_size
will allow very large values of len (> U16_MAX - sizeof(cmd))
and can cause a buffer overflow. Fix the check to cover this case.
In addition, ensure the mailbox entry_size is not too small,
since this can also bypass the above check.

Signed-off-by: Lior David <qca_liord@xxxxxxxxxxxxxxxx>
Signed-off-by: Maya Erez <qca_merez@xxxxxxxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/wireless/ath/wil6210/interrupt.c | 22 +++++++++++++++++++++-
drivers/net/wireless/ath/wil6210/wmi.c | 2 +-
2 files changed, 22 insertions(+), 2 deletions(-)

--- a/drivers/net/wireless/ath/wil6210/interrupt.c
+++ b/drivers/net/wireless/ath/wil6210/interrupt.c
@@ -356,6 +356,25 @@ static void wil_cache_mbox_regs(struct w
wil_mbox_ring_le2cpus(&wil->mbox_ctl.tx);
}

+static bool wil_validate_mbox_regs(struct wil6210_priv *wil)
+{
+ size_t min_size = sizeof(struct wil6210_mbox_hdr) +
+ sizeof(struct wmi_cmd_hdr);
+
+ if (wil->mbox_ctl.rx.entry_size < min_size) {
+ wil_err(wil, "rx mbox entry too small (%d)\n",
+ wil->mbox_ctl.rx.entry_size);
+ return false;
+ }
+ if (wil->mbox_ctl.tx.entry_size < min_size) {
+ wil_err(wil, "tx mbox entry too small (%d)\n",
+ wil->mbox_ctl.tx.entry_size);
+ return false;
+ }
+
+ return true;
+}
+
static irqreturn_t wil6210_irq_misc(int irq, void *cookie)
{
struct wil6210_priv *wil = cookie;
@@ -391,7 +410,8 @@ static irqreturn_t wil6210_irq_misc(int
if (isr & ISR_MISC_FW_READY) {
wil_dbg_irq(wil, "IRQ: FW ready\n");
wil_cache_mbox_regs(wil);
- set_bit(wil_status_mbox_ready, wil->status);
+ if (wil_validate_mbox_regs(wil))
+ set_bit(wil_status_mbox_ready, wil->status);
/**
* Actual FW ready indicated by the
* WMI_FW_READY_EVENTID
--- a/drivers/net/wireless/ath/wil6210/wmi.c
+++ b/drivers/net/wireless/ath/wil6210/wmi.c
@@ -209,7 +209,7 @@ static int __wmi_send(struct wil6210_pri
uint retry;
int rc = 0;

- if (sizeof(cmd) + len > r->entry_size) {
+ if (len > r->entry_size - sizeof(cmd)) {
wil_err(wil, "WMI size too large: %d bytes, max is %d\n",
(int)(sizeof(cmd) + len), r->entry_size);
return -ERANGE;