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From:   Nikita Zhandarovich <n.zhandarovich@fintech.ru>
To:     Larry Finger <Larry.Finger@lwfinger.net>
CC:     Nikita Zhandarovich <n.zhandarovich@fintech.ru>,
        Kalle Valo <kvalo@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "John W. Linville" <linville@tuxdriver.com>,
        <linux-wireless@vger.kernel.org>, <b43-dev@lists.infradead.org>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <lvc-project@linuxtesting.org>,
        Natalia Petrova <n.petrova@fintech.ru>
Subject: [PATCH v2] b43legacy: Add checking for null for ssb_get_devtypedata(dev)
Date:   Tue, 18 Apr 2023 07:29:18 -0700
Message-ID: <20230418142918.70510-1-n.zhandarovich@fintech.ru>
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Since second call of ssb_get_devtypedata() may fail as well as the
first one, the NULL return value in 'wl' will be later dereferenced in
calls to b43legacy_one_core_attach() and schedule_work().

Instead of merely warning about this failure with
B43legacy_WARN_ON(), properly return with error to avoid any further
NULL pointer dereferences.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 75388acd0cd8 ("[B43LEGACY]: add mac80211-based driver for legacy BCM43xx devices")
Co-developed-by: Natalia Petrova <n.petrova@fintech.ru>
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
---
v2: fix issues with overlooked null-ptr-dereferences pointed out by
Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/all/Y+eb9mZntfe6rO3v@corigine.com/ 

 drivers/net/wireless/broadcom/b43legacy/main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/broadcom/b43legacy/main.c b/drivers/net/wireless/broadcom/b43legacy/main.c
index 760136638a95..5a706dd0b1a4 100644
--- a/drivers/net/wireless/broadcom/b43legacy/main.c
+++ b/drivers/net/wireless/broadcom/b43legacy/main.c
@@ -3857,7 +3857,11 @@ static int b43legacy_probe(struct ssb_device *dev,
 		if (err)
 			goto out;
 		wl = ssb_get_devtypedata(dev);
-		B43legacy_WARN_ON(!wl);
+		if (!wl) {
+			B43legacy_WARN_ON(!wl);
+			err = -ENODEV;
+			goto out;
+		}
 	}
 	err = b43legacy_one_core_attach(dev, wl);
 	if (err)
-- 
2.25.1