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/scsi/arm/msgqueue.h | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 drivers/scsi/arm/msgqueue.h (limited to 'drivers/scsi/arm/msgqueue.h') diff --git a/drivers/scsi/arm/msgqueue.h b/drivers/scsi/arm/msgqueue.h new file mode 100644 index 000000000..4bcc400f5 --- /dev/null +++ b/drivers/scsi/arm/msgqueue.h @@ -0,0 +1,79 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/drivers/acorn/scsi/msgqueue.h + * + * Copyright (C) 1997 Russell King + * + * message queue handling + */ +#ifndef MSGQUEUE_H +#define MSGQUEUE_H + +struct message { + char msg[8]; + int length; + int fifo; +}; + +struct msgqueue_entry { + struct message msg; + struct msgqueue_entry *next; +}; + +#define NR_MESSAGES 4 + +typedef struct { + struct msgqueue_entry *qe; + struct msgqueue_entry *free; + struct msgqueue_entry entries[NR_MESSAGES]; +} MsgQueue_t; + +/* + * Function: void msgqueue_initialise(MsgQueue_t *msgq) + * Purpose : initialise a message queue + * Params : msgq - queue to initialise + */ +extern void msgqueue_initialise(MsgQueue_t *msgq); + +/* + * Function: void msgqueue_free(MsgQueue_t *msgq) + * Purpose : free a queue + * Params : msgq - queue to free + */ +extern void msgqueue_free(MsgQueue_t *msgq); + +/* + * Function: int msgqueue_msglength(MsgQueue_t *msgq) + * Purpose : calculate the total length of all messages on the message queue + * Params : msgq - queue to examine + * Returns : number of bytes of messages in queue + */ +extern int msgqueue_msglength(MsgQueue_t *msgq); + +/* + * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) + * Purpose : return a message & its length + * Params : msgq - queue to obtain message from + * : msgno - message number + * Returns : pointer to message string, or NULL + */ +extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno); + +/* + * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...) + * Purpose : add a message onto a message queue + * Params : msgq - queue to add message on + * length - length of message + * ... - message bytes + * Returns : != 0 if successful + */ +extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...); + +/* + * Function: void msgqueue_flush(MsgQueue_t *msgq) + * Purpose : flush all messages from message queue + * Params : msgq - queue to flush + */ +extern void msgqueue_flush(MsgQueue_t *msgq); + +#endif -- cgit v1.3.1