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 --- include/net/dst_ops.h | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 include/net/dst_ops.h (limited to 'include/net/dst_ops.h') diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h new file mode 100644 index 000000000..3a9001a04 --- /dev/null +++ b/include/net/dst_ops.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _NET_DST_OPS_H +#define _NET_DST_OPS_H +#include +#include +#include + +struct dst_entry; +struct kmem_cachep; +struct net_device; +struct sk_buff; +struct sock; +struct net; + +struct dst_ops { + unsigned short family; + unsigned int gc_thresh; + + void (*gc)(struct dst_ops *ops); + struct dst_entry * (*check)(struct dst_entry *, __u32 cookie); + unsigned int (*default_advmss)(const struct dst_entry *); + unsigned int (*mtu)(const struct dst_entry *); + u32 * (*cow_metrics)(struct dst_entry *, unsigned long); + void (*destroy)(struct dst_entry *); + void (*ifdown)(struct dst_entry *, + struct net_device *dev); + void (*negative_advice)(struct sock *sk, struct dst_entry *); + void (*link_failure)(struct sk_buff *); + void (*update_pmtu)(struct dst_entry *dst, struct sock *sk, + struct sk_buff *skb, u32 mtu, + bool confirm_neigh); + void (*redirect)(struct dst_entry *dst, struct sock *sk, + struct sk_buff *skb); + int (*local_out)(struct net *net, struct sock *sk, struct sk_buff *skb); + struct neighbour * (*neigh_lookup)(const struct dst_entry *dst, + struct sk_buff *skb, + const void *daddr); + void (*confirm_neigh)(const struct dst_entry *dst, + const void *daddr); + + struct kmem_cache *kmem_cachep; + + struct percpu_counter pcpuc_entries ____cacheline_aligned_in_smp; +}; + +static inline int dst_entries_get_fast(struct dst_ops *dst) +{ + return percpu_counter_read_positive(&dst->pcpuc_entries); +} + +static inline int dst_entries_get_slow(struct dst_ops *dst) +{ + return percpu_counter_sum_positive(&dst->pcpuc_entries); +} + +#define DST_PERCPU_COUNTER_BATCH 32 +static inline void dst_entries_add(struct dst_ops *dst, int val) +{ + percpu_counter_add_batch(&dst->pcpuc_entries, val, + DST_PERCPU_COUNTER_BATCH); +} + +static inline int dst_entries_init(struct dst_ops *dst) +{ + return percpu_counter_init(&dst->pcpuc_entries, 0, GFP_KERNEL); +} + +static inline void dst_entries_destroy(struct dst_ops *dst) +{ + percpu_counter_destroy(&dst->pcpuc_entries); +} + +#endif -- cgit v1.3.1