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 083E628ED for ; Mon, 12 Dec 2022 13:52:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0B8EC433EF; Mon, 12 Dec 2022 13:52:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670853136; bh=KSUA4w4D8iVRFHCvRuAbwbHEXE09wLHrZQ8gcCDa8bM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q7Ls1Y9oPSEcFRQx2CDMOM0j3MPmp58FMJ2XoMzCiNF00MzfixAt40/69Apx+/Xfs DFk7mNXXFlJeFWljSZWC7UJMt3F2NhaUcuvcW2T/fwjUbQYkKl7gx625SPqdRB23T5 4XgFmo0L50uno7HUOwCOceNxbvtGIRfVUaW+293k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Anastasia Belova , Jiri Kosina Subject: [PATCH 4.14 17/38] HID: hid-lg4ff: Add check for empty lbuf Date: Mon, 12 Dec 2022 14:19:18 +0100 Message-Id: <20221212130912.982279390@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221212130912.069170932@linuxfoundation.org> References: <20221212130912.069170932@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 @@ -880,6 +880,12 @@ 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);