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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>,
        Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
        Christoph Hellwig <hch@lst.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 075/306] nvmet: avoid integer overflow in the discard code
Date:   Wed, 27 Nov 2019 21:28:45 +0100
Message-Id: <20191127203120.350833425@linuxfoundation.org>
In-Reply-To: <20191127203114.766709977@linuxfoundation.org>
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From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit 8eacd1bd21d6913ec27e6120e9a8733352e191d3 ]

Although I'm not sure whether it is a good idea to support large discard
commands, I think integer overflow for discard ranges larger than 4 GB
should be avoided. This patch avoids that smatch reports the following:

drivers/nvme/target/io-cmd-file.c:249:1 nvmet_file_execute_discard() warn: should '((range.nlb)) << req->ns->blksize_shift' be a 64 bit type?

Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/target/io-cmd-file.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/target/io-cmd-file.c b/drivers/nvme/target/io-cmd-file.c
index 81a9dc5290a87..39d972e2595f0 100644
--- a/drivers/nvme/target/io-cmd-file.c
+++ b/drivers/nvme/target/io-cmd-file.c
@@ -246,7 +246,8 @@ static void nvmet_file_execute_discard(struct nvmet_req *req)
 			break;
 
 		offset = le64_to_cpu(range.slba) << req->ns->blksize_shift;
-		len = le32_to_cpu(range.nlb) << req->ns->blksize_shift;
+		len = le32_to_cpu(range.nlb);
+		len <<= req->ns->blksize_shift;
 		if (offset + len > req->ns->size) {
 			ret = NVME_SC_LBA_RANGE | NVME_SC_DNR;
 			break;
-- 
2.20.1