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 --- tools/perf/util/cacheline.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 tools/perf/util/cacheline.h (limited to 'tools/perf/util/cacheline.h') diff --git a/tools/perf/util/cacheline.h b/tools/perf/util/cacheline.h new file mode 100644 index 000000000..fe6d5b60a --- /dev/null +++ b/tools/perf/util/cacheline.h @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef PERF_CACHELINE_H +#define PERF_CACHELINE_H + +#include + +int __pure cacheline_size(void); + + +/* + * Some architectures have 'Adjacent Cacheline Prefetch' feature, + * which performs like the cacheline size being doubled. + */ +static inline u64 cl_address(u64 address, bool double_cl) +{ + u64 size = cacheline_size(); + + if (double_cl) + size *= 2; + + /* return the cacheline of the address */ + return (address & ~(size - 1)); +} + +static inline u64 cl_offset(u64 address, bool double_cl) +{ + u64 size = cacheline_size(); + + if (double_cl) + size *= 2; + + /* return the offset inside cacheline */ + return (address & (size - 1)); +} + +#endif // PERF_CACHELINE_H -- cgit v1.3.1