linux-kernel - [PATCH 1/5] spi: amd: Limit max transfer and message size

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220706100626.1234731-2-cristian.ciocaltea@collabora.com>
Date:   Wed,  6 Jul 2022 13:06:22 +0300
From:   Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
To:     Mark Brown <broonie@...nel.org>,
        Sanjay R Mehta <sanju.mehta@....com>
Cc:     linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...labora.com, Anastasios Vacharakis <vacharakis@...ail.de>,
        cristian.ciocaltea@...labora.com
Subject: [PATCH 1/5] spi: amd: Limit max transfer and message size

Enabling the SPI CS35L41 audio codec driver for Steam Deck [1]
revealed a problem with the current AMD SPI controller driver
implementation, consisting of an unrecoverable system hang.

The issue can be prevented if we ensure the max transfer size
and the max message size do not exceed the FIFO buffer size.

According to the implementation of the downstream driver, the
AMD SPI controller is not able to handle more than 70 bytes per
transfer, which corresponds to the size of the FIFO buffer.

Hence, let's fix this by setting the SPI limits mentioned above.

[1] https://lore.kernel.org/r/20220621213819.262537-1-cristian.ciocaltea@collabora.com

Reported-by: Anastasios Vacharakis <vacharakis@...ail.de>
Fixes: bbb336f39efc ("spi: spi-amd: Add AMD SPI controller driver support")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
---
 drivers/spi/spi-amd.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/spi/spi-amd.c b/drivers/spi/spi-amd.c
index cba6a4486c24..efdcbe6c4c26 100644
--- a/drivers/spi/spi-amd.c
+++ b/drivers/spi/spi-amd.c
@@ -33,6 +33,7 @@
 #define AMD_SPI_RX_COUNT_REG	0x4B
 #define AMD_SPI_STATUS_REG	0x4C
 
+#define AMD_SPI_FIFO_SIZE	70
 #define AMD_SPI_MEM_SIZE	200
 
 /* M_CMD OP codes for SPI */
@@ -270,6 +271,11 @@ static int amd_spi_master_transfer(struct spi_master *master,
 	return 0;
 }
 
+static size_t amd_spi_max_transfer_size(struct spi_device *spi)
+{
+	return AMD_SPI_FIFO_SIZE;
+}
+
 static int amd_spi_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -302,6 +308,8 @@ static int amd_spi_probe(struct platform_device *pdev)
 	master->flags = SPI_MASTER_HALF_DUPLEX;
 	master->setup = amd_spi_master_setup;
 	master->transfer_one_message = amd_spi_master_transfer;
+	master->max_transfer_size = amd_spi_max_transfer_size;
+	master->max_message_size = amd_spi_max_transfer_size;
 
 	/* Register the controller with SPI framework */
 	err = devm_spi_register_master(dev, master);
-- 
2.36.1