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 --- net/9p/protocol.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) create mode 100644 net/9p/protocol.h (limited to 'net/9p/protocol.h') diff --git a/net/9p/protocol.h b/net/9p/protocol.h new file mode 100644 index 000000000..ad2283d1f --- /dev/null +++ b/net/9p/protocol.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * 9P Protocol Support Code + * + * Copyright (C) 2008 by Eric Van Hensbergen + * + * Base on code from Anthony Liguori + * Copyright (C) 2008 by IBM, Corp. + */ + +size_t p9_msg_buf_size(struct p9_client *c, enum p9_msg_t type, + const char *fmt, va_list ap); +int p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt, + va_list ap); +int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...); +int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type); +int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu); +void p9pdu_reset(struct p9_fcall *pdu); +size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size); -- cgit v1.3.1