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/skbuff.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 net/rxrpc/skbuff.c (limited to 'net/rxrpc/skbuff.c') diff --git a/net/rxrpc/skbuff.c b/net/rxrpc/skbuff.c new file mode 100644 index 000000000..e2169d1a1 --- /dev/null +++ b/net/rxrpc/skbuff.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Socket buffer accounting + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include "ar-internal.h" + +#define select_skb_count(skb) (&rxrpc_n_rx_skbs) + +/* + * Note the allocation or reception of a socket buffer. + */ +void rxrpc_new_skb(struct sk_buff *skb, enum rxrpc_skb_trace why) +{ + int n = atomic_inc_return(select_skb_count(skb)); + trace_rxrpc_skb(skb, refcount_read(&skb->users), n, why); +} + +/* + * Note the re-emergence of a socket buffer from a queue or buffer. + */ +void rxrpc_see_skb(struct sk_buff *skb, enum rxrpc_skb_trace why) +{ + if (skb) { + int n = atomic_read(select_skb_count(skb)); + trace_rxrpc_skb(skb, refcount_read(&skb->users), n, why); + } +} + +/* + * Note the addition of a ref on a socket buffer. + */ +void rxrpc_get_skb(struct sk_buff *skb, enum rxrpc_skb_trace why) +{ + int n = atomic_inc_return(select_skb_count(skb)); + trace_rxrpc_skb(skb, refcount_read(&skb->users), n, why); + skb_get(skb); +} + +/* + * Note the destruction of a socket buffer. + */ +void rxrpc_free_skb(struct sk_buff *skb, enum rxrpc_skb_trace why) +{ + if (skb) { + int n = atomic_dec_return(select_skb_count(skb)); + trace_rxrpc_skb(skb, refcount_read(&skb->users), n, why); + consume_skb(skb); + } +} + +/* + * Clear a queue of socket buffers. + */ +void rxrpc_purge_queue(struct sk_buff_head *list) +{ + struct sk_buff *skb; + + while ((skb = skb_dequeue((list))) != NULL) { + int n = atomic_dec_return(select_skb_count(skb)); + trace_rxrpc_skb(skb, refcount_read(&skb->users), n, + rxrpc_skb_put_purge); + consume_skb(skb); + } +} -- cgit v1.3.1