From nobody Tue Oct 7 19:24:13 2025 Received: from smtp76.ord1d.emailsrvr.com (smtp76.ord1d.emailsrvr.com [184.106.54.76]) (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 E7EFD29DB96 for ; Mon, 7 Jul 2025 13:16:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=184.106.54.76 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751894207; cv=none; b=gndbNI3MvnhLeMipEbVBnzV8gGDTiNDavwBpG/aXsuxBcaBgEG9Pl57bpMUg3fnyrPcJBOR0r5dpi8Cs0ipiCc2gpQzq7DkArbze/EF+4G31fPX3rsN9vNp42vklTJZr1EGwMGWAL7LRykFVSj6xrv3CTqEmz6dsjtJkeDQilNQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751894207; c=relaxed/simple; bh=+MQNrRajYzgRvJT9hs9COOwWego2BbwUc1ZTW5K/jsc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=UCg/G/wHrMjQsK/Asan4cUhRawHg2FE46EX7AHUDcxp8GYvJrBMqgSGbTdKnTSGQXu/jCjsKggl9Cb7dtTTsW5cHvPV6mPLnx+vfto5dIM7mBf6X6K6r1cXBs98H1V3m1VHCnVNadXmZpPF48e7n917UyCFQ6+RpnoYNYUsg7ZY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mev.co.uk; spf=pass smtp.mailfrom=mev.co.uk; dkim=pass (1024-bit key) header.d=mev.co.uk header.i=@mev.co.uk header.b=hjHI+TV1; arc=none smtp.client-ip=184.106.54.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mev.co.uk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mev.co.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mev.co.uk header.i=@mev.co.uk header.b="hjHI+TV1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mev.co.uk; s=20221208-6x11dpa4; t=1751893769; bh=+MQNrRajYzgRvJT9hs9COOwWego2BbwUc1ZTW5K/jsc=; h=From:To:Subject:Date:From; b=hjHI+TV16vJ28lA73bl0OFuRRqePNCgVDLiDuZP/HJJZg87fNC0Ojta2iE8khUHPE gCJMNhj7OKHyet9Ojt85ak7bv/7IXbZZ0+Rsy1heGDMBfRXU1NaepvAlycdkSa42uu sFc00qaOazzoqCRMzqbBaBLCqcg2P6BV5+H/qHeU= X-Auth-ID: abbotti@mev.co.uk Received: by smtp10.relay.ord1d.emailsrvr.com (Authenticated sender: abbotti-AT-mev.co.uk) with ESMTPSA id 5C9C4A0219; Mon, 7 Jul 2025 09:09:28 -0400 (EDT) From: Ian Abbott To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , Ian Abbott , H Hartley Sweeten , syzbot+c52293513298e0fd9a94@syzkaller.appspotmail.com, "Enju, Kohei" , stable@vger.kernel.org Subject: [PATCH] comedi: das16m1: Fix bit shift out of bounds Date: Mon, 7 Jul 2025 14:09:08 +0100 Message-ID: <20250707130908.70758-1-abbotti@mev.co.uk> X-Mailer: git-send-email 2.47.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Classification-ID: c1dbfb42-cac4-4372-8215-e9f6cc597d88-1-1 Content-Type: text/plain; charset="utf-8" When checking for a supported IRQ number, the following test is used: /* only irqs 2, 3, 4, 5, 6, 7, 10, 11, 12, 14, and 15 are valid */ if ((1 << it->options[1]) & 0xdcfc) { However, `it->options[i]` is an unchecked `int` value from userspace, so the shift amount could be negative or out of bounds. Fix the test by requiring `it->options[1]` to be within bounds before proceeding with the original test. Reported-by: syzbot+c52293513298e0fd9a94@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3Dc52293513298e0fd9a94 Fixes: 729988507680 ("staging: comedi: das16m1: tidy up the irq support in = das16m1_attach()") Tested-by: syzbot+c52293513298e0fd9a94@syzkaller.appspotmail.com Suggested-by: "Enju, Kohei" Cc: # 5.13+ Signed-off-by: Ian Abbott --- Patch does not apply cleanly to longterm kernels 5.4.x and 5.10.x. --- drivers/comedi/drivers/das16m1.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/comedi/drivers/das16m1.c b/drivers/comedi/drivers/das1= 6m1.c index b8ea737ad3d1..1b638f5b5a4f 100644 --- a/drivers/comedi/drivers/das16m1.c +++ b/drivers/comedi/drivers/das16m1.c @@ -522,7 +522,8 @@ static int das16m1_attach(struct comedi_device *dev, devpriv->extra_iobase =3D dev->iobase + DAS16M1_8255_IOBASE; =20 /* only irqs 2, 3, 4, 5, 6, 7, 10, 11, 12, 14, and 15 are valid */ - if ((1 << it->options[1]) & 0xdcfc) { + if (it->options[1] >=3D 2 && it->options[1] <=3D 15 && + (1 << it->options[1]) & 0xdcfc) { ret =3D request_irq(it->options[1], das16m1_interrupt, 0, dev->board_name, dev); if (ret =3D=3D 0) --=20 2.47.2