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/mfd/ocelot.h | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 drivers/mfd/ocelot.h (limited to 'drivers/mfd/ocelot.h') diff --git a/drivers/mfd/ocelot.h b/drivers/mfd/ocelot.h new file mode 100644 index 000000000..b8bc2f148 --- /dev/null +++ b/drivers/mfd/ocelot.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0 OR MIT */ +/* Copyright 2021, 2022 Innovative Advantage Inc. */ + +#ifndef _MFD_OCELOT_H +#define _MFD_OCELOT_H + +#include + +struct device; +struct regmap; +struct resource; + +/** + * struct ocelot_ddata - Private data for an external Ocelot chip + * @gcb_regmap: General Configuration Block regmap. Used for + * operations like chip reset. + * @cpuorg_regmap: CPU Device Origin Block regmap. Used for operations + * like SPI bus configuration. + * @spi_padding_bytes: Number of padding bytes that must be thrown out before + * read data gets returned. This is calculated during + * initialization based on bus speed. + * @dummy_buf: Zero-filled buffer of spi_padding_bytes size. The dummy + * bytes that will be sent out between the address and + * data of a SPI read operation. + */ +struct ocelot_ddata { + struct regmap *gcb_regmap; + struct regmap *cpuorg_regmap; + int spi_padding_bytes; + void *dummy_buf; +}; + +int ocelot_chip_reset(struct device *dev); +int ocelot_core_init(struct device *dev); + +/* SPI-specific routines that won't be necessary for other interfaces */ +struct regmap *ocelot_spi_init_regmap(struct device *dev, + const struct resource *res); + +#define OCELOT_SPI_BYTE_ORDER_LE 0x00000000 +#define OCELOT_SPI_BYTE_ORDER_BE 0x81818181 + +#ifdef __LITTLE_ENDIAN +#define OCELOT_SPI_BYTE_ORDER OCELOT_SPI_BYTE_ORDER_LE +#else +#define OCELOT_SPI_BYTE_ORDER OCELOT_SPI_BYTE_ORDER_BE +#endif + +#endif -- cgit v1.3.1