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 --- arch/mips/rb532/setup.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) create mode 100644 arch/mips/rb532/setup.c (limited to 'arch/mips/rb532/setup.c') diff --git a/arch/mips/rb532/setup.c b/arch/mips/rb532/setup.c new file mode 100644 index 000000000..51af9d374 --- /dev/null +++ b/arch/mips/rb532/setup.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * setup.c - boot time setup code + */ + +#include +#include + +#include +#include +#include +#include + +#include +#include + +struct pci_reg __iomem *pci_reg; +EXPORT_SYMBOL(pci_reg); + +static struct resource pci0_res[] = { + { + .name = "pci_reg0", + .start = PCI0_BASE_ADDR, + .end = PCI0_BASE_ADDR + sizeof(struct pci_reg), + .flags = IORESOURCE_MEM, + } +}; + +static void rb_machine_restart(char *command) +{ + /* just jump to the reset vector */ + writel(0x80000001, IDT434_REG_BASE + RST); + ((void (*)(void)) KSEG1ADDR(0x1FC00000u))(); +} + +static void rb_machine_halt(void) +{ + for (;;) + continue; +} + +void __init plat_mem_setup(void) +{ + u32 val; + + _machine_restart = rb_machine_restart; + _machine_halt = rb_machine_halt; + pm_power_off = rb_machine_halt; + + set_io_port_base(KSEG1); + + pci_reg = ioremap(pci0_res[0].start, + pci0_res[0].end - pci0_res[0].start); + if (!pci_reg) { + printk(KERN_ERR "Could not remap PCI registers\n"); + return; + } + + val = __raw_readl(&pci_reg->pcic); + val &= 0xFFFFFF7; + __raw_writel(val, (void *)&pci_reg->pcic); + +#ifdef CONFIG_PCI + /* Enable PCI interrupts in EPLD Mask register */ + *epld_mask = 0x0; + *(epld_mask + 1) = 0x0; +#endif + write_c0_wired(0); +} + +const char *get_system_type(void) +{ + switch (mips_machtype) { + case MACH_MIKROTIK_RB532A: + return "Mikrotik RB532A"; + break; + default: + return "Mikrotik RB532"; + break; + } +} -- cgit v1.3.1