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/misc/sram.h | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 drivers/misc/sram.h (limited to 'drivers/misc/sram.h') diff --git a/drivers/misc/sram.h b/drivers/misc/sram.h new file mode 100644 index 000000000..397205b8b --- /dev/null +++ b/drivers/misc/sram.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Defines for the SRAM driver + */ +#ifndef __SRAM_H +#define __SRAM_H + +struct sram_config { + int (*init)(void); + bool map_only_reserved; +}; + +struct sram_partition { + void __iomem *base; + + struct gen_pool *pool; + struct bin_attribute battr; + struct mutex lock; + struct list_head list; +}; + +struct sram_dev { + const struct sram_config *config; + + struct device *dev; + void __iomem *virt_base; + bool no_memory_wc; + + struct gen_pool *pool; + + struct sram_partition *partition; + u32 partitions; +}; + +struct sram_reserve { + struct list_head list; + u32 start; + u32 size; + struct resource res; + bool export; + bool pool; + bool protect_exec; + const char *label; +}; + +#ifdef CONFIG_SRAM_EXEC +int sram_check_protect_exec(struct sram_dev *sram, struct sram_reserve *block, + struct sram_partition *part); +int sram_add_protect_exec(struct sram_partition *part); +#else +static inline int sram_check_protect_exec(struct sram_dev *sram, + struct sram_reserve *block, + struct sram_partition *part) +{ + return -ENODEV; +} + +static inline int sram_add_protect_exec(struct sram_partition *part) +{ + return -ENODEV; +} +#endif /* CONFIG_SRAM_EXEC */ +#endif /* __SRAM_H */ -- cgit v1.3.1