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/overlayfs/params.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 fs/overlayfs/params.h (limited to 'fs/overlayfs/params.h') diff --git a/fs/overlayfs/params.h b/fs/overlayfs/params.h new file mode 100644 index 000000000..ffd53cdd8 --- /dev/null +++ b/fs/overlayfs/params.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include +#include + +struct ovl_fs; +struct ovl_config; + +extern const struct fs_parameter_spec ovl_parameter_spec[]; +extern const struct constant_table ovl_parameter_redirect_dir[]; + +/* The set of options that user requested explicitly via mount options */ +struct ovl_opt_set { + bool metacopy; + bool redirect; + bool nfs_export; + bool index; +}; + +#define OVL_MAX_STACK 500 + +struct ovl_fs_context_layer { + char *name; + struct path path; +}; + +struct ovl_fs_context { + struct path upper; + struct path work; + size_t capacity; + size_t nr; /* includes nr_data */ + size_t nr_data; + struct ovl_opt_set set; + struct ovl_fs_context_layer *lower; + char *lowerdir_all; /* user provided lowerdir string */ + bool casefold_set; +}; + +int ovl_init_fs_context(struct fs_context *fc); +void ovl_free_fs(struct ovl_fs *ofs); +int ovl_fs_params_verify(const struct ovl_fs_context *ctx, + struct ovl_config *config); +int ovl_show_options(struct seq_file *m, struct dentry *dentry); +const char *ovl_xino_mode(struct ovl_config *config); -- cgit v1.3.1