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/pnode.h | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 fs/pnode.h (limited to 'fs/pnode.h') diff --git a/fs/pnode.h b/fs/pnode.h new file mode 100644 index 000000000..b029db225 --- /dev/null +++ b/fs/pnode.h @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/fs/pnode.h + * + * (C) Copyright IBM Corporation 2005. + */ +#ifndef _LINUX_PNODE_H +#define _LINUX_PNODE_H + +#include +#include "mount.h" + +#define IS_MNT_SHARED(m) ((m)->mnt_t_flags & T_SHARED) +#define IS_MNT_SLAVE(m) ((m)->mnt_master) +#define IS_MNT_NEW(m) (!(m)->mnt_ns) +#define CLEAR_MNT_SHARED(m) ((m)->mnt_t_flags &= ~T_SHARED) +#define IS_MNT_UNBINDABLE(m) ((m)->mnt_t_flags & T_UNBINDABLE) +#define IS_MNT_MARKED(m) ((m)->mnt_t_flags & T_MARKED) +#define SET_MNT_MARK(m) ((m)->mnt_t_flags |= T_MARKED) +#define CLEAR_MNT_MARK(m) ((m)->mnt_t_flags &= ~T_MARKED) +#define IS_MNT_LOCKED(m) ((m)->mnt.mnt_flags & MNT_LOCKED) + +#define CL_EXPIRE 0x01 +#define CL_SLAVE 0x02 +#define CL_COPY_UNBINDABLE 0x04 +#define CL_MAKE_SHARED 0x08 +#define CL_PRIVATE 0x10 +#define CL_COPY_MNT_NS_FILE 0x40 + +/* + * EXCL[namespace_sem] + */ +static inline void set_mnt_shared(struct mount *mnt) +{ + mnt->mnt_t_flags &= ~T_SHARED_MASK; + mnt->mnt_t_flags |= T_SHARED; +} + +static inline bool peers(const struct mount *m1, const struct mount *m2) +{ + return m1->mnt_group_id == m2->mnt_group_id && m1->mnt_group_id; +} + +void change_mnt_propagation(struct mount *, int); +void bulk_make_private(struct list_head *); +int propagate_mnt(struct mount *, struct mountpoint *, struct mount *, + struct hlist_head *); +void propagate_umount(struct list_head *); +int propagate_mount_busy(struct mount *, int); +void propagate_mount_unlock(struct mount *); +void mnt_release_group_id(struct mount *); +int get_dominating_id(struct mount *mnt, const struct path *root); +int mnt_get_count(struct mount *mnt); +void mnt_set_mountpoint(struct mount *, struct mountpoint *, + struct mount *); +void mnt_change_mountpoint(struct mount *parent, struct mountpoint *mp, + struct mount *mnt); +struct mount *copy_tree(struct mount *, struct dentry *, int); +bool is_path_reachable(struct mount *, struct dentry *, + const struct path *root); +int count_mounts(struct mnt_namespace *ns, struct mount *mnt); +bool propagation_would_overmount(const struct mount *from, + const struct mount *to, + const struct mountpoint *mp); +#endif /* _LINUX_PNODE_H */ -- cgit v1.3.1