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 --- fs/ntfs/malloc.h | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 fs/ntfs/malloc.h (limited to 'fs/ntfs/malloc.h') diff --git a/fs/ntfs/malloc.h b/fs/ntfs/malloc.h new file mode 100644 index 000000000..706842573 --- /dev/null +++ b/fs/ntfs/malloc.h @@ -0,0 +1,77 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * malloc.h - NTFS kernel memory handling. Part of the Linux-NTFS project. + * + * Copyright (c) 2001-2005 Anton Altaparmakov + */ + +#ifndef _LINUX_NTFS_MALLOC_H +#define _LINUX_NTFS_MALLOC_H + +#include +#include +#include + +/** + * __ntfs_malloc - allocate memory in multiples of pages + * @size: number of bytes to allocate + * @gfp_mask: extra flags for the allocator + * + * Internal function. You probably want ntfs_malloc_nofs()... + * + * Allocates @size bytes of memory, rounded up to multiples of PAGE_SIZE and + * returns a pointer to the allocated memory. + * + * If there was insufficient memory to complete the request, return NULL. + * Depending on @gfp_mask the allocation may be guaranteed to succeed. + */ +static inline void *__ntfs_malloc(unsigned long size, gfp_t gfp_mask) +{ + if (likely(size <= PAGE_SIZE)) { + BUG_ON(!size); + /* kmalloc() has per-CPU caches so is faster for now. */ + return kmalloc(PAGE_SIZE, gfp_mask & ~__GFP_HIGHMEM); + /* return (void *)__get_free_page(gfp_mask); */ + } + if (likely((size >> PAGE_SHIFT) < totalram_pages())) + return __vmalloc(size, gfp_mask); + return NULL; +} + +/** + * ntfs_malloc_nofs - allocate memory in multiples of pages + * @size: number of bytes to allocate + * + * Allocates @size bytes of memory, rounded up to multiples of PAGE_SIZE and + * returns a pointer to the allocated memory. + * + * If there was insufficient memory to complete the request, return NULL. + */ +static inline void *ntfs_malloc_nofs(unsigned long size) +{ + return __ntfs_malloc(size, GFP_NOFS | __GFP_HIGHMEM); +} + +/** + * ntfs_malloc_nofs_nofail - allocate memory in multiples of pages + * @size: number of bytes to allocate + * + * Allocates @size bytes of memory, rounded up to multiples of PAGE_SIZE and + * returns a pointer to the allocated memory. + * + * This function guarantees that the allocation will succeed. It will sleep + * for as long as it takes to complete the allocation. + * + * If there was insufficient memory to complete the request, return NULL. + */ +static inline void *ntfs_malloc_nofs_nofail(unsigned long size) +{ + return __ntfs_malloc(size, GFP_NOFS | __GFP_HIGHMEM | __GFP_NOFAIL); +} + +static inline void ntfs_free(void *addr) +{ + kvfree(addr); +} + +#endif /* _LINUX_NTFS_MALLOC_H */ -- cgit v1.3.1