linux-kernel - [PATCH AUTOSEL 6.1 17/17] nvme-core: check for too small lba shift

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Date:   Mon,  4 Dec 2023 15:35:02 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Keith Busch <kbusch@...nel.org>, Jens Axboe <axboe@...nel.dk>,
        Sasha Levin <sashal@...nel.org>, sagi@...mberg.me,
        linux-nvme@...ts.infradead.org
Subject: [PATCH AUTOSEL 6.1 17/17] nvme-core: check for too small lba shift

From: Keith Busch <kbusch@...nel.org>

[ Upstream commit 74fbc88e161424b3b96a22b23a8e3e1edab9d05c ]

The block layer doesn't support logical block sizes smaller than 512
bytes. The nvme spec doesn't support that small either, but the driver
isn't checking to make sure the device responded with usable data.
Failing to catch this will result in a kernel bug, either from a
division by zero when stacking, or a zero length bio.

Reviewed-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Keith Busch <kbusch@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/nvme/host/core.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 0590c0b81fca9..b0db3b54d69a3 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1922,9 +1922,10 @@ static void nvme_update_disk_info(struct gendisk *disk,
 
 	/*
 	 * The block layer can't support LBA sizes larger than the page size
-	 * yet, so catch this early and don't allow block I/O.
+	 * or smaller than a sector size yet, so catch this early and don't
+	 * allow block I/O.
 	 */
-	if (ns->lba_shift > PAGE_SHIFT) {
+	if (ns->lba_shift > PAGE_SHIFT || ns->lba_shift < SECTOR_SHIFT) {
 		capacity = 0;
 		bs = (1 << 9);
 	}
-- 
2.42.0