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 --- security/lsm.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 security/lsm.h (limited to 'security/lsm.h') diff --git a/security/lsm.h b/security/lsm.h new file mode 100644 index 000000000..32f808ad4 --- /dev/null +++ b/security/lsm.h @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LSM functions + */ + +#ifndef _LSM_H_ +#define _LSM_H_ + +#include +#include +#include + +/* LSM debugging */ +extern bool lsm_debug; +#define lsm_pr(...) pr_info(__VA_ARGS__) +#define lsm_pr_cont(...) pr_cont(__VA_ARGS__) +#define lsm_pr_dbg(...) \ + do { \ + if (lsm_debug) \ + pr_info(__VA_ARGS__); \ + } while (0) + +/* List of configured LSMs */ +extern unsigned int lsm_active_cnt; +extern const struct lsm_id *lsm_idlist[]; + +/* LSM blob configuration */ +extern struct lsm_blob_sizes blob_sizes; + +/* LSM blob caches */ +extern struct kmem_cache *lsm_file_cache; +extern struct kmem_cache *lsm_backing_file_cache; +extern struct kmem_cache *lsm_inode_cache; + +/* LSM blob allocators */ +int lsm_cred_alloc(struct cred *cred, gfp_t gfp); +int lsm_task_alloc(struct task_struct *task); + +/* LSM framework initializers */ + +#ifdef CONFIG_SECURITYFS +int securityfs_init(void); +#else +static inline int securityfs_init(void) +{ + return 0; +} +#endif /* CONFIG_SECURITYFS */ + +#endif /* _LSM_H_ */ -- cgit v1.3.1