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 A19A2FBF6 for ; Mon, 15 May 2023 17:56:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C21CC433D2; Mon, 15 May 2023 17:56:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684173379; bh=gGtlz5Bh1DZ9JLIl2sTaswDJtwHZ2ffk0UdIg1mwC8Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hfHQH/qSECXeaNeaeutC6L42vDownGgINAiUhuhCfqOb/vW7gDNU6iWUf8K0pJWcw ViRncjyiWv4ScnfNgE/JcMJcjI/IqXe/PziO5/hD+iZlpdOGEgpZ27o4rELjmmyJZR q1LkE3/l6M5M924oKKawZ6nE4Fs0b59FOWwHqecc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dan Carpenter , Hans Verkuil , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 5.4 046/282] media: av7110: prevent underflow in write_ts_to_decoder() Date: Mon, 15 May 2023 18:27:04 +0200 Message-Id: <20230515161723.641833351@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230515161722.146344674@linuxfoundation.org> References: <20230515161722.146344674@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: Dan Carpenter [ Upstream commit eed9496a0501357aa326ddd6b71408189ed872eb ] The buf[4] value comes from the user via ts_play(). It is a value in the u8 range. The final length we pass to av7110_ipack_instant_repack() is "len - (buf[4] + 1) - 4" so add a check to ensure that the length is not negative. It's not clear that passing a negative len value does anything bad necessarily, but it's not best practice. With the new bounds checking the "if (!len)" condition is no longer possible or required so remove that. Fixes: fd46d16d602a ("V4L/DVB (11759): dvb-ttpci: Add TS replay capability") Signed-off-by: Dan Carpenter Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/pci/ttpci/av7110_av.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/media/pci/ttpci/av7110_av.c b/drivers/media/pci/ttpci/av7110_av.c index ea9f7d0058a21..e201d5a56bc65 100644 --- a/drivers/media/pci/ttpci/av7110_av.c +++ b/drivers/media/pci/ttpci/av7110_av.c @@ -822,10 +822,10 @@ static int write_ts_to_decoder(struct av7110 *av7110, int type, const u8 *buf, s av7110_ipack_flush(ipack); if (buf[3] & ADAPT_FIELD) { + if (buf[4] > len - 1 - 4) + return 0; len -= buf[4] + 1; buf += buf[4] + 1; - if (!len) - return 0; } av7110_ipack_instant_repack(buf + 4, len - 4, ipack); -- 2.39.2