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/rxrpc/insecure.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 net/rxrpc/insecure.c (limited to 'net/rxrpc/insecure.c') diff --git a/net/rxrpc/insecure.c b/net/rxrpc/insecure.c new file mode 100644 index 000000000..0b39046bd --- /dev/null +++ b/net/rxrpc/insecure.c @@ -0,0 +1,94 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Null security operations. + * + * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include "ar-internal.h" + +static int none_init_connection_security(struct rxrpc_connection *conn, + struct rxrpc_key_token *token) +{ + return 0; +} + +/* + * Allocate an appropriately sized buffer for the amount of data remaining. + */ +static struct rxrpc_txbuf *none_alloc_txbuf(struct rxrpc_call *call, size_t remain, gfp_t gfp) +{ + return rxrpc_alloc_data_txbuf(call, umin(remain, RXRPC_JUMBO_DATALEN), 1, gfp); +} + +static int none_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb) +{ + txb->pkt_len = txb->len; + if (txb->len == RXRPC_JUMBO_DATALEN) + txb->jumboable = true; + return 0; +} + +static int none_verify_packet(struct rxrpc_call *call, struct sk_buff *skb) +{ + return 0; +} + +static void none_free_call_crypto(struct rxrpc_call *call) +{ +} + +static bool none_validate_challenge(struct rxrpc_connection *conn, + struct sk_buff *skb) +{ + rxrpc_abort_conn(conn, skb, RX_PROTOCOL_ERROR, -EPROTO, + rxrpc_eproto_rxnull_challenge); + return true; +} + +static int none_sendmsg_respond_to_challenge(struct sk_buff *challenge, + struct msghdr *msg) +{ + return -EINVAL; +} + +static int none_verify_response(struct rxrpc_connection *conn, + struct sk_buff *response_skb, + void *response, unsigned int len) +{ + return rxrpc_abort_conn(conn, response_skb, RX_PROTOCOL_ERROR, -EPROTO, + rxrpc_eproto_rxnull_response); +} + +static void none_clear(struct rxrpc_connection *conn) +{ +} + +static int none_init(void) +{ + return 0; +} + +static void none_exit(void) +{ +} + +/* + * RxRPC Kerberos-based security + */ +const struct rxrpc_security rxrpc_no_security = { + .name = "none", + .security_index = RXRPC_SECURITY_NONE, + .init = none_init, + .exit = none_exit, + .init_connection_security = none_init_connection_security, + .free_call_crypto = none_free_call_crypto, + .alloc_txbuf = none_alloc_txbuf, + .secure_packet = none_secure_packet, + .verify_packet = none_verify_packet, + .validate_challenge = none_validate_challenge, + .sendmsg_respond_to_challenge = none_sendmsg_respond_to_challenge, + .verify_response = none_verify_response, + .clear = none_clear, +}; -- cgit v1.3.1