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/efi/reboot.c | 78 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 drivers/firmware/efi/reboot.c (limited to 'drivers/firmware/efi/reboot.c') diff --git a/drivers/firmware/efi/reboot.c b/drivers/firmware/efi/reboot.c new file mode 100644 index 000000000..ceae84c19 --- /dev/null +++ b/drivers/firmware/efi/reboot.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2014 Intel Corporation; author Matt Fleming + * Copyright (c) 2014 Red Hat, Inc., Mark Salter + */ +#include +#include + +static struct sys_off_handler *efi_sys_off_handler; + +int efi_reboot_quirk_mode = -1; + +void efi_reboot(enum reboot_mode reboot_mode, const char *__unused) +{ + const char *str[] = { "cold", "warm", "shutdown", "platform" }; + int efi_mode, cap_reset_mode; + + if (!efi_rt_services_supported(EFI_RT_SUPPORTED_RESET_SYSTEM)) + return; + + switch (reboot_mode) { + case REBOOT_WARM: + case REBOOT_SOFT: + efi_mode = EFI_RESET_WARM; + break; + default: + efi_mode = EFI_RESET_COLD; + break; + } + + /* + * If a quirk forced an EFI reset mode, always use that. + */ + if (efi_reboot_quirk_mode != -1) + efi_mode = efi_reboot_quirk_mode; + + if (efi_capsule_pending(&cap_reset_mode)) { + if (efi_mode != cap_reset_mode) + printk(KERN_CRIT "efi: %s reset requested but pending " + "capsule update requires %s reset... Performing " + "%s reset.\n", str[efi_mode], str[cap_reset_mode], + str[cap_reset_mode]); + efi_mode = cap_reset_mode; + } + + efi.reset_system(efi_mode, EFI_SUCCESS, 0, NULL); +} + +bool __weak efi_poweroff_required(void) +{ + return false; +} + +static int efi_power_off(struct sys_off_data *data) +{ + efi.reset_system(EFI_RESET_SHUTDOWN, EFI_SUCCESS, 0, NULL); + + return NOTIFY_DONE; +} + +static int __init efi_shutdown_init(void) +{ + if (!efi_rt_services_supported(EFI_RT_SUPPORTED_RESET_SYSTEM)) + return -ENODEV; + + if (efi_poweroff_required()) { + /* SYS_OFF_PRIO_FIRMWARE + 1 so that it runs before acpi_power_off */ + efi_sys_off_handler = + register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, + SYS_OFF_PRIO_FIRMWARE + 1, + efi_power_off, NULL); + if (IS_ERR(efi_sys_off_handler)) + return PTR_ERR(efi_sys_off_handler); + } + + return 0; +} +late_initcall(efi_shutdown_init); -- cgit v1.3.1