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 --- include/asm-generic/irqflags.h | 67 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) create mode 100644 include/asm-generic/irqflags.h (limited to 'include/asm-generic/irqflags.h') diff --git a/include/asm-generic/irqflags.h b/include/asm-generic/irqflags.h new file mode 100644 index 000000000..19ccbf483 --- /dev/null +++ b/include/asm-generic/irqflags.h @@ -0,0 +1,67 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_GENERIC_IRQFLAGS_H +#define __ASM_GENERIC_IRQFLAGS_H + +/* + * All architectures should implement at least the first two functions, + * usually inline assembly will be the best way. + */ +#ifndef ARCH_IRQ_DISABLED +#define ARCH_IRQ_DISABLED 0 +#define ARCH_IRQ_ENABLED 1 +#endif + +/* read interrupt enabled status */ +#ifndef arch_local_save_flags +unsigned long arch_local_save_flags(void); +#endif + +/* set interrupt enabled status */ +#ifndef arch_local_irq_restore +void arch_local_irq_restore(unsigned long flags); +#endif + +/* get status and disable interrupts */ +#ifndef arch_local_irq_save +static inline unsigned long arch_local_irq_save(void) +{ + unsigned long flags; + flags = arch_local_save_flags(); + arch_local_irq_restore(ARCH_IRQ_DISABLED); + return flags; +} +#endif + +/* test flags */ +#ifndef arch_irqs_disabled_flags +static inline int arch_irqs_disabled_flags(unsigned long flags) +{ + return flags == ARCH_IRQ_DISABLED; +} +#endif + +/* unconditionally enable interrupts */ +#ifndef arch_local_irq_enable +static inline void arch_local_irq_enable(void) +{ + arch_local_irq_restore(ARCH_IRQ_ENABLED); +} +#endif + +/* unconditionally disable interrupts */ +#ifndef arch_local_irq_disable +static inline void arch_local_irq_disable(void) +{ + arch_local_irq_restore(ARCH_IRQ_DISABLED); +} +#endif + +/* test hardware interrupt enable bit */ +#ifndef arch_irqs_disabled +static inline int arch_irqs_disabled(void) +{ + return arch_irqs_disabled_flags(arch_local_save_flags()); +} +#endif + +#endif /* __ASM_GENERIC_IRQFLAGS_H */ -- cgit v1.3.1