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/firmware/imx/sm-cpu.c | 85 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 drivers/firmware/imx/sm-cpu.c (limited to 'drivers/firmware/imx/sm-cpu.c') diff --git a/drivers/firmware/imx/sm-cpu.c b/drivers/firmware/imx/sm-cpu.c new file mode 100644 index 000000000..091b014f7 --- /dev/null +++ b/drivers/firmware/imx/sm-cpu.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2025 NXP + */ + +#include +#include +#include +#include +#include +#include + +static const struct scmi_imx_cpu_proto_ops *imx_cpu_ops; +static struct scmi_protocol_handle *ph; + +int scmi_imx_cpu_reset_vector_set(u32 cpuid, u64 vector, bool start, bool boot, + bool resume) +{ + if (!ph) + return -EPROBE_DEFER; + + return imx_cpu_ops->cpu_reset_vector_set(ph, cpuid, vector, start, + boot, resume); +} +EXPORT_SYMBOL(scmi_imx_cpu_reset_vector_set); + +int scmi_imx_cpu_start(u32 cpuid, bool start) +{ + if (!ph) + return -EPROBE_DEFER; + + if (start) + return imx_cpu_ops->cpu_start(ph, cpuid, true); + + return imx_cpu_ops->cpu_start(ph, cpuid, false); +}; +EXPORT_SYMBOL(scmi_imx_cpu_start); + +int scmi_imx_cpu_started(u32 cpuid, bool *started) +{ + if (!ph) + return -EPROBE_DEFER; + + if (!started) + return -EINVAL; + + return imx_cpu_ops->cpu_started(ph, cpuid, started); +}; +EXPORT_SYMBOL(scmi_imx_cpu_started); + +static int scmi_imx_cpu_probe(struct scmi_device *sdev) +{ + const struct scmi_handle *handle = sdev->handle; + + if (!handle) + return -ENODEV; + + if (imx_cpu_ops) { + dev_err(&sdev->dev, "sm cpu already initialized\n"); + return -EEXIST; + } + + imx_cpu_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_IMX_CPU, &ph); + if (IS_ERR(imx_cpu_ops)) + return PTR_ERR(imx_cpu_ops); + + return 0; +} + +static const struct scmi_device_id scmi_id_table[] = { + { SCMI_PROTOCOL_IMX_CPU, "imx-cpu" }, + { }, +}; +MODULE_DEVICE_TABLE(scmi, scmi_id_table); + +static struct scmi_driver scmi_imx_cpu_driver = { + .name = "scmi-imx-cpu", + .probe = scmi_imx_cpu_probe, + .id_table = scmi_id_table, +}; +module_scmi_driver(scmi_imx_cpu_driver); + +MODULE_AUTHOR("Peng Fan "); +MODULE_DESCRIPTION("IMX SM CPU driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1