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, 30 insertions, 0 deletions

diff --git a/net/mac80211/tkip.h b/net/mac80211/tkip.h
new file mode 100644
index 000000000..9d2f8bd36
--- /dev/null
+++ b/net/mac80211/tkip.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2002-2004, Instant802 Networks, Inc.
+ */
+
+#ifndef TKIP_H
+#define TKIP_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+#include "key.h"
+
+int ieee80211_tkip_encrypt_data(struct arc4_ctx *ctx,
+				struct ieee80211_key *key,
+				struct sk_buff *skb,
+				u8 *payload, size_t payload_len);
+
+enum {
+	TKIP_DECRYPT_OK = 0,
+	TKIP_DECRYPT_NO_EXT_IV = -1,
+	TKIP_DECRYPT_INVALID_KEYIDX = -2,
+	TKIP_DECRYPT_REPLAY = -3,
+};
+int ieee80211_tkip_decrypt_data(struct arc4_ctx *ctx,
+				struct ieee80211_key *key,
+				u8 *payload, size_t payload_len, u8 *ta,
+				u8 *ra, int only_iv, int queue,
+				u32 *out_iv32, u16 *out_iv16);
+
+#endif /* TKIP_H */