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/btrfs/export.h | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 fs/btrfs/export.h (limited to 'fs/btrfs/export.h') diff --git a/fs/btrfs/export.h b/fs/btrfs/export.h new file mode 100644 index 000000000..464582273 --- /dev/null +++ b/fs/btrfs/export.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_EXPORT_H +#define BTRFS_EXPORT_H + +#include +#include + +struct dentry; +struct super_block; + +extern const struct export_operations btrfs_export_ops; + +struct btrfs_fid { + u64 objectid; + u64 root_objectid; + u32 gen; + + u64 parent_objectid; + u32 parent_gen; + + u64 parent_root_objectid; +} __attribute__ ((packed)); + +struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, + u64 root_objectid, u64 generation); +struct dentry *btrfs_get_parent(struct dentry *child); + +#endif -- cgit v1.3.1