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 --- drivers/mtd/ubi/wl.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 drivers/mtd/ubi/wl.h (limited to 'drivers/mtd/ubi/wl.h') diff --git a/drivers/mtd/ubi/wl.h b/drivers/mtd/ubi/wl.h new file mode 100644 index 000000000..a69169c35 --- /dev/null +++ b/drivers/mtd/ubi/wl.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef UBI_WL_H +#define UBI_WL_H +#ifdef CONFIG_MTD_UBI_FASTMAP +static void update_fastmap_work_fn(struct work_struct *wrk); +static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root); +static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi); +static struct ubi_wl_entry *next_peb_for_wl(struct ubi_device *ubi, + bool need_fill); +static bool need_wear_leveling(struct ubi_device *ubi); +static void ubi_fastmap_close(struct ubi_device *ubi); +static inline void ubi_fastmap_init(struct ubi_device *ubi, int *count) +{ + if (ubi->fm_disabled) + ubi->fm_pool_rsv_cnt = 0; + /* Reserve enough LEBs to store two fastmaps and to fill pools. */ + *count += (ubi->fm_size / ubi->leb_size) * 2 + ubi->fm_pool_rsv_cnt; + INIT_WORK(&ubi->fm_work, update_fastmap_work_fn); +} +static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi, + struct ubi_wl_entry *e, + struct rb_root *root); +#else /* !CONFIG_MTD_UBI_FASTMAP */ +static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi); +static inline void ubi_fastmap_close(struct ubi_device *ubi) { } +static inline void ubi_fastmap_init(struct ubi_device *ubi, int *count) { } +static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi, + struct ubi_wl_entry *e, + struct rb_root *root) { + return e; +} +#endif /* CONFIG_MTD_UBI_FASTMAP */ +#endif /* UBI_WL_H */ -- cgit v1.3.1