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/bitops/le.h | 64 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 include/asm-generic/bitops/le.h (limited to 'include/asm-generic/bitops/le.h') diff --git a/include/asm-generic/bitops/le.h b/include/asm-generic/bitops/le.h new file mode 100644 index 000000000..d51beff60 --- /dev/null +++ b/include/asm-generic/bitops/le.h @@ -0,0 +1,64 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_BITOPS_LE_H_ +#define _ASM_GENERIC_BITOPS_LE_H_ + +#include +#include + +#if defined(__LITTLE_ENDIAN) + +#define BITOP_LE_SWIZZLE 0 + +#elif defined(__BIG_ENDIAN) + +#define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7) + +#endif + + +static inline int test_bit_le(int nr, const void *addr) +{ + return test_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline void set_bit_le(int nr, void *addr) +{ + set_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline void clear_bit_le(int nr, void *addr) +{ + clear_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline void __set_bit_le(int nr, void *addr) +{ + __set_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline void __clear_bit_le(int nr, void *addr) +{ + __clear_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline int test_and_set_bit_le(int nr, void *addr) +{ + return test_and_set_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline int test_and_clear_bit_le(int nr, void *addr) +{ + return test_and_clear_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline int __test_and_set_bit_le(int nr, void *addr) +{ + return __test_and_set_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline int __test_and_clear_bit_le(int nr, void *addr) +{ + return __test_and_clear_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +#endif /* _ASM_GENERIC_BITOPS_LE_H_ */ -- cgit v1.3.1