From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 96C5615E84 for ; Mon, 23 Oct 2023 11:29:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bLQzCKNk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE367C43391; Mon, 23 Oct 2023 11:29:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698060573; bh=o/TeZjgkjfcgKpeQQeOjM7bZ4Y+bVXFuzN0D9SbN2qo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bLQzCKNkV7J+uCT+U7nOP/dq/ebhZvUsIpObnfaaGqCcPY95ZWAFnjTP+ZyrAqjAi ln7IZu6DpgGxG5icSOgh/AS4d1bF9y1Ed690QCQajYChqV3LiNEzKHrWsM5U+iO9Th ULrWQxsXZ3tzO8vp/L1bXAKtxvJR7AniBolUzrEI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Javier Carrasco , Peter Korsgaard , Jakub Kicinski , syzbot+1f53a30781af65d2c955@syzkaller.appspotmail.com Subject: [PATCH 5.4 021/123] net: usb: dm9601: fix uninitialized variable use in dm9601_mdio_read Date: Mon, 23 Oct 2023 12:56:19 +0200 Message-ID: <20231023104818.446932573@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231023104817.691299567@linuxfoundation.org> References: <20231023104817.691299567@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Javier Carrasco commit 8f8abb863fa5a4cc18955c6a0e17af0ded3e4a76 upstream. syzbot has found an uninit-value bug triggered by the dm9601 driver [1]. This error happens because the variable res is not updated if the call to dm_read_shared_word returns an error. In this particular case -EPROTO was returned and res stayed uninitialized. This can be avoided by checking the return value of dm_read_shared_word and propagating the error if the read operation failed. [1] https://syzkaller.appspot.com/bug?extid=1f53a30781af65d2c955 Cc: stable@vger.kernel.org Signed-off-by: Javier Carrasco Reported-and-tested-by: syzbot+1f53a30781af65d2c955@syzkaller.appspotmail.com Acked-by: Peter Korsgaard Fixes: d0374f4f9c35cdfbee0 ("USB: Davicom DM9601 usbnet driver") Link: https://lore.kernel.org/r/20231009-topic-dm9601_uninit_mdio_read-v2-1-f2fe39739b6c@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/dm9601.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/drivers/net/usb/dm9601.c +++ b/drivers/net/usb/dm9601.c @@ -221,13 +221,18 @@ static int dm9601_mdio_read(struct net_d struct usbnet *dev = netdev_priv(netdev); __le16 res; + int err; if (phy_id) { netdev_dbg(dev->net, "Only internal phy supported\n"); return 0; } - dm_read_shared_word(dev, 1, loc, &res); + err = dm_read_shared_word(dev, 1, loc, &res); + if (err < 0) { + netdev_err(dev->net, "MDIO read error: %d\n", err); + return err; + } netdev_dbg(dev->net, "dm9601_mdio_read() phy_id=0x%02x, loc=0x%02x, returns=0x%04x\n",