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/squashfs/decompressor.h | 54 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 fs/squashfs/decompressor.h (limited to 'fs/squashfs/decompressor.h') diff --git a/fs/squashfs/decompressor.h b/fs/squashfs/decompressor.h new file mode 100644 index 000000000..19ab60834 --- /dev/null +++ b/fs/squashfs/decompressor.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef DECOMPRESSOR_H +#define DECOMPRESSOR_H +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 + * Phillip Lougher + * + * decompressor.h + */ + +#include + +struct squashfs_decompressor { + void *(*init)(struct squashfs_sb_info *, void *); + void *(*comp_opts)(struct squashfs_sb_info *, void *, int); + void (*free)(void *); + int (*decompress)(struct squashfs_sb_info *, void *, + struct bio *, int, int, struct squashfs_page_actor *); + int id; + char *name; + int alloc_buffer; + int supported; +}; + +static inline void *squashfs_comp_opts(struct squashfs_sb_info *msblk, + void *buff, int length) +{ + return msblk->decompressor->comp_opts ? + msblk->decompressor->comp_opts(msblk, buff, length) : NULL; +} + +#ifdef CONFIG_SQUASHFS_XZ +extern const struct squashfs_decompressor squashfs_xz_comp_ops; +#endif + +#ifdef CONFIG_SQUASHFS_LZ4 +extern const struct squashfs_decompressor squashfs_lz4_comp_ops; +#endif + +#ifdef CONFIG_SQUASHFS_LZO +extern const struct squashfs_decompressor squashfs_lzo_comp_ops; +#endif + +#ifdef CONFIG_SQUASHFS_ZLIB +extern const struct squashfs_decompressor squashfs_zlib_comp_ops; +#endif + +#ifdef CONFIG_SQUASHFS_ZSTD +extern const struct squashfs_decompressor squashfs_zstd_comp_ops; +#endif + +#endif -- cgit v1.3.1