openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

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 <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 138 insertions, 0 deletions

diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
new file mode 100644
index 000000000..ffda15318
--- /dev/null
+++ b/include/net/netns/ipv6.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * ipv6 in net namespaces
+ */
+
+#include <net/inet_frag.h>
+
+#ifndef __NETNS_IPV6_H__
+#define __NETNS_IPV6_H__
+#include <net/dst_ops.h>
+#include <uapi/linux/icmpv6.h>
+
+struct ctl_table_header;
+
+struct netns_sysctl_ipv6 {
+#ifdef CONFIG_SYSCTL
+	struct ctl_table_header *hdr;
+	struct ctl_table_header *route_hdr;
+	struct ctl_table_header *icmp_hdr;
+	struct ctl_table_header *frags_hdr;
+	struct ctl_table_header *xfrm6_hdr;
+#endif
+	int flush_delay;
+	int ip6_rt_max_size;
+	int ip6_rt_gc_min_interval;
+	int ip6_rt_gc_timeout;
+	int ip6_rt_gc_interval;
+	int ip6_rt_gc_elasticity;
+	int ip6_rt_mtu_expires;
+	int ip6_rt_min_advmss;
+	u32 multipath_hash_fields;
+	u8 multipath_hash_policy;
+
+	__cacheline_group_begin(sysctl_ipv6_flowlabel);
+	u8 flowlabel_consistency;
+	u8 auto_flowlabels;
+	u8 flowlabel_state_ranges;
+	__cacheline_group_end(sysctl_ipv6_flowlabel);
+
+	u8 icmpv6_echo_ignore_all;
+	u8 icmpv6_echo_ignore_multicast;
+	u8 icmpv6_echo_ignore_anycast;
+	int icmpv6_time;
+	DECLARE_BITMAP(icmpv6_ratemask, ICMPV6_MSG_MAX + 1);
+	unsigned long *icmpv6_ratemask_ptr;
+	u8 anycast_src_echo_reply;
+	u8 bindv6only;
+	u8 ip_nonlocal_bind;
+	u8 fwmark_reflect;
+	int idgen_retries;
+	int idgen_delay;
+	int flowlabel_reflect;
+	int max_dst_opts_cnt;
+	int max_hbh_opts_cnt;
+	int max_dst_opts_len;
+	int max_hbh_opts_len;
+	int seg6_flowlabel;
+	u32 ioam6_id;
+	u64 ioam6_id_wide;
+	u8 skip_notify_on_dev_down;
+	u8 fib_notify_on_flag_change;
+	u8 icmpv6_error_anycast_as_unicast;
+	u8 icmpv6_errors_extension_mask;
+};
+
+struct netns_ipv6 {
+	/* Keep ip6_dst_ops at the beginning of netns_sysctl_ipv6 */
+	struct dst_ops		ip6_dst_ops;
+
+	struct netns_sysctl_ipv6 sysctl;
+	struct ipv6_devconf	*devconf_all;
+	struct ipv6_devconf	*devconf_dflt;
+	struct inet_peer_base	*peers;
+	struct fqdir		*fqdir;
+	struct fib6_info	*fib6_null_entry;
+	struct rt6_info		*ip6_null_entry;
+	struct rt6_statistics   *rt6_stats;
+	struct timer_list       ip6_fib_timer;
+	struct hlist_head       *fib_table_hash;
+	spinlock_t		fib_table_hash_lock;
+	struct fib6_table       *fib6_main_tbl;
+	struct list_head	fib6_walkers;
+	rwlock_t		fib6_walker_lock;
+	spinlock_t		fib6_gc_lock;
+	atomic_t		ip6_rt_gc_expire;
+	unsigned long		ip6_rt_last_gc;
+	unsigned char		flowlabel_has_excl;
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+	bool			fib6_has_custom_rules;
+	unsigned int		fib6_rules_require_fldissect;
+#ifdef CONFIG_IPV6_SUBTREES
+	unsigned int		fib6_routes_require_src;
+#endif
+	struct rt6_info         *ip6_prohibit_entry;
+	struct rt6_info         *ip6_blk_hole_entry;
+	struct fib6_table       *fib6_local_tbl;
+	struct fib_rules_ops    *fib6_rules_ops;
+#endif
+	struct sock             *ndisc_sk;
+	struct sock             *tcp_sk;
+	struct sock             *igmp_sk;
+	struct sock		*mc_autojoin_sk;
+
+	struct hlist_head	*inet6_addr_lst;
+	spinlock_t		addrconf_hash_lock;
+	struct delayed_work	addr_chk_work;
+
+#ifdef CONFIG_IPV6_MROUTE
+#ifndef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES
+	struct mr_table		*mrt6;
+#else
+	struct list_head	mr6_tables;
+	struct fib_rules_ops	*mr6_rules_ops;
+#endif
+	struct fib_notifier_ops	*ip6mr_notifier_ops;
+	atomic_t		ipmr_seq;
+	struct mutex		mfc_mutex;
+#endif
+	atomic_t		dev_addr_genid;
+	atomic_t		fib6_sernum;
+	struct seg6_pernet_data *seg6_data;
+	struct fib_notifier_ops	*notifier_ops;
+	int			flowlabel_count;
+	struct {
+		struct hlist_head head;
+		spinlock_t	lock;
+		u32		seq;
+	} ip6addrlbl_table;
+	struct ioam6_pernet_data *ioam6_data;
+};
+
+#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
+struct netns_nf_frag {
+	struct fqdir	*fqdir;
+};
+#endif
+
+#endif