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/powerpc/sysdev/ipic.h | 56 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 arch/powerpc/sysdev/ipic.h (limited to 'arch/powerpc/sysdev/ipic.h') diff --git a/arch/powerpc/sysdev/ipic.h b/arch/powerpc/sysdev/ipic.h new file mode 100644 index 000000000..45ab61406 --- /dev/null +++ b/arch/powerpc/sysdev/ipic.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * IPIC private definitions and structure. + * + * Maintainer: Kumar Gala + * + * Copyright 2005 Freescale Semiconductor, Inc + */ +#ifndef __IPIC_H__ +#define __IPIC_H__ + +#include + +#define NR_IPIC_INTS 128 + +/* External IRQS */ +#define IPIC_IRQ_EXT0 48 +#define IPIC_IRQ_EXT1 17 +#define IPIC_IRQ_EXT7 23 + +/* Default Priority Registers */ +#define IPIC_PRIORITY_DEFAULT 0x05309770 + +/* System Global Interrupt Configuration Register */ +#define SICFR_IPSA 0x00010000 +#define SICFR_IPSB 0x00020000 +#define SICFR_IPSC 0x00040000 +#define SICFR_IPSD 0x00080000 +#define SICFR_MPSA 0x00200000 +#define SICFR_MPSB 0x00400000 + +/* System External Interrupt Mask Register */ +#define SEMSR_SIRQ0 0x00008000 + +/* System Error Control Register */ +#define SERCR_MCPR 0x00000001 + +struct ipic { + volatile u32 __iomem *regs; + + /* The remapper for this IPIC */ + struct irq_domain *irqhost; +}; + +struct ipic_info { + u8 ack; /* pending register offset from base if the irq + supports ack operation */ + u8 mask; /* mask register offset from base */ + u8 prio; /* priority register offset from base */ + u8 force; /* force register offset from base */ + u8 bit; /* register bit position (as per doc) + bit mask = 1 << (31 - bit) */ + u8 prio_mask; /* priority mask value */ +}; + +#endif /* __IPIC_H__ */ -- cgit v1.3.1