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 91C4328ED for ; Mon, 12 Dec 2022 13:50:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E42ECC433D2; Mon, 12 Dec 2022 13:50:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670853044; bh=55LRY2CZ6QAmnSz7+2cnqjbDvw0PzXkBfwFtJwW8dqw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L8MtzYm2SKzxbmgXEeHN7HeorGUJgn/YqDg2Ig8TYz6kgguZV/uLGGI3SlW40dc8n j5UohZOvhVVdaVGXYaRLRxu4jyQS5vI9JvbqLvTebu+UP2BFQW0MTi8aPct07b9rN/ n5lKEASu76b+mQ5nbiNogOTKLV7Idwl8T2Jvf4tE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Anastasia Belova , Jiri Kosina Subject: [PATCH 4.19 20/49] HID: hid-lg4ff: Add check for empty lbuf Date: Mon, 12 Dec 2022 14:18:58 +0100 Message-Id: <20221212130914.701449554@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221212130913.666185567@linuxfoundation.org> References: <20221212130913.666185567@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Anastasia Belova commit d180b6496143cd360c5d5f58ae4b9a8229c1f344 upstream. If an empty buf is received, lbuf is also empty. So lbuf is accessed by index -1. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: f31a2de3fe36 ("HID: hid-lg4ff: Allow switching of Logitech gaming wheels between compatibility modes") Signed-off-by: Anastasia Belova Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-lg4ff.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/hid/hid-lg4ff.c +++ b/drivers/hid/hid-lg4ff.c @@ -878,6 +878,12 @@ static ssize_t lg4ff_alternate_modes_sto return -ENOMEM; i = strlen(lbuf); + + if (i == 0) { + kfree(lbuf); + return -EINVAL; + } + if (lbuf[i-1] == '\n') { if (i == 1) { kfree(lbuf);