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/testing/memblock/internal.h | 69 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 tools/testing/memblock/internal.h (limited to 'tools/testing/memblock/internal.h') diff --git a/tools/testing/memblock/internal.h b/tools/testing/memblock/internal.h new file mode 100644 index 000000000..b6b1d147f --- /dev/null +++ b/tools/testing/memblock/internal.h @@ -0,0 +1,69 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _MM_INTERNAL_H +#define _MM_INTERNAL_H + +/* + * Enable memblock_dbg() messages + */ +#ifdef MEMBLOCK_DEBUG +static int memblock_debug = 1; +#endif + +#define pr_warn_ratelimited(fmt, ...) printf(fmt, ##__VA_ARGS__) + +#define K(x) ((x) << (PAGE_SHIFT-10)) + +bool mirrored_kernelcore = false; + +struct page {}; +static inline void *page_address(struct page *page) +{ + BUG(); + return page; +} + +static inline struct page *virt_to_page(void *virt) +{ + BUG(); + return virt; +} + +void memblock_free_pages(unsigned long pfn, unsigned int order) +{ +} + +static inline void accept_memory(phys_addr_t start, unsigned long size) +{ +} + +unsigned long free_reserved_area(void *start, void *end, int poison, const char *s); +void free_reserved_page(struct page *page); + +static inline bool deferred_pages_enabled(void) +{ + return false; +} + +#define for_each_valid_pfn(pfn, start_pfn, end_pfn) \ + for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++) + +static inline void *kasan_reset_tag(const void *addr) +{ + return (void *)addr; +} + +static inline bool __is_kernel(unsigned long addr) +{ + return false; +} + +#define for_each_valid_pfn(pfn, start_pfn, end_pfn) \ + for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++) + +static inline void init_deferred_page(unsigned long pfn, int nid) +{ +} + +#define __SetPageReserved(p) ((void)(p)) + +#endif -- cgit v1.3.1