From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- drivers/input/misc/ad714x-spi.c | 103 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 drivers/input/misc/ad714x-spi.c (limited to 'drivers/input/misc/ad714x-spi.c') diff --git a/drivers/input/misc/ad714x-spi.c b/drivers/input/misc/ad714x-spi.c new file mode 100644 index 000000000..eb13b4cd6 --- /dev/null +++ b/drivers/input/misc/ad714x-spi.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * AD714X CapTouch Programmable Controller driver (SPI bus) + * + * Copyright 2009-2011 Analog Devices Inc. + */ + +#include /* BUS_SPI */ +#include +#include +#include +#include +#include "ad714x.h" + +#define AD714x_SPI_CMD_PREFIX 0xE000 /* bits 15:11 */ +#define AD714x_SPI_READ BIT(10) + +static int ad714x_spi_read(struct ad714x_chip *chip, + unsigned short reg, unsigned short *data, size_t len) +{ + struct spi_device *spi = to_spi_device(chip->dev); + struct spi_message message; + struct spi_transfer xfer[2]; + int i; + int error; + + spi_message_init(&message); + memset(xfer, 0, sizeof(xfer)); + + chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | + AD714x_SPI_READ | reg); + xfer[0].tx_buf = &chip->xfer_buf[0]; + xfer[0].len = sizeof(chip->xfer_buf[0]); + spi_message_add_tail(&xfer[0], &message); + + xfer[1].rx_buf = &chip->xfer_buf[1]; + xfer[1].len = sizeof(chip->xfer_buf[1]) * len; + spi_message_add_tail(&xfer[1], &message); + + error = spi_sync(spi, &message); + if (unlikely(error)) { + dev_err(chip->dev, "SPI read error: %d\n", error); + return error; + } + + for (i = 0; i < len; i++) + data[i] = be16_to_cpu(chip->xfer_buf[i + 1]); + + return 0; +} + +static int ad714x_spi_write(struct ad714x_chip *chip, + unsigned short reg, unsigned short data) +{ + struct spi_device *spi = to_spi_device(chip->dev); + int error; + + chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg); + chip->xfer_buf[1] = cpu_to_be16(data); + + error = spi_write(spi, (u8 *)chip->xfer_buf, + 2 * sizeof(*chip->xfer_buf)); + if (unlikely(error)) { + dev_err(chip->dev, "SPI write error: %d\n", error); + return error; + } + + return 0; +} + +static int ad714x_spi_probe(struct spi_device *spi) +{ + struct ad714x_chip *chip; + int err; + + spi->bits_per_word = 8; + err = spi_setup(spi); + if (err < 0) + return err; + + chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq, + ad714x_spi_read, ad714x_spi_write); + if (IS_ERR(chip)) + return PTR_ERR(chip); + + spi_set_drvdata(spi, chip); + + return 0; +} + +static struct spi_driver ad714x_spi_driver = { + .driver = { + .name = "ad714x_captouch", + .pm = pm_sleep_ptr(&ad714x_pm), + }, + .probe = ad714x_spi_probe, +}; + +module_spi_driver(ad714x_spi_driver); + +MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver"); +MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1