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/soc/microchip/mpfs-control-scb.c | 40 ++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 drivers/soc/microchip/mpfs-control-scb.c (limited to 'drivers/soc/microchip/mpfs-control-scb.c') diff --git a/drivers/soc/microchip/mpfs-control-scb.c b/drivers/soc/microchip/mpfs-control-scb.c new file mode 100644 index 000000000..8dda5704a --- /dev/null +++ b/drivers/soc/microchip/mpfs-control-scb.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include + +static const struct mfd_cell mpfs_control_scb_devs[] = { + MFD_CELL_NAME("mpfs-tvs"), +}; + +static int mpfs_control_scb_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + + return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE, + mpfs_control_scb_devs, + ARRAY_SIZE(mpfs_control_scb_devs), NULL, 0, + NULL); +} + +static const struct of_device_id mpfs_control_scb_of_match[] = { + { .compatible = "microchip,mpfs-control-scb", }, + {}, +}; +MODULE_DEVICE_TABLE(of, mpfs_control_scb_of_match); + +static struct platform_driver mpfs_control_scb_driver = { + .driver = { + .name = "mpfs-control-scb", + .of_match_table = mpfs_control_scb_of_match, + }, + .probe = mpfs_control_scb_probe, +}; +module_platform_driver(mpfs_control_scb_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Conor Dooley "); +MODULE_DESCRIPTION("PolarFire SoC control scb driver"); -- cgit v1.3.1