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, 99 insertions, 0 deletions

diff --git a/net/bluetooth/eir.h b/net/bluetooth/eir.h
new file mode 100644
index 000000000..9372db83f
--- /dev/null
+++ b/net/bluetooth/eir.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * BlueZ - Bluetooth protocol stack for Linux
+ *
+ * Copyright (C) 2021 Intel Corporation
+ */
+
+#include <linux/unaligned.h>
+
+void eir_create(struct hci_dev *hdev, u8 *data);
+
+u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr, u8 size);
+u8 eir_create_scan_rsp(struct hci_dev *hdev, u8 instance, u8 *ptr);
+u8 eir_create_per_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr);
+
+u8 eir_append_local_name(struct hci_dev *hdev, u8 *eir, u8 ad_len);
+u8 eir_append_appearance(struct hci_dev *hdev, u8 *ptr, u8 ad_len);
+u8 eir_append_service_data(u8 *eir, u16 eir_len, u16 uuid, u8 *data,
+			   u8 data_len);
+
+static inline u16 eir_precalc_len(u8 data_len)
+{
+	return sizeof(u8) * 2 + data_len;
+}
+
+static inline u16 eir_append_data(u8 *eir, u16 eir_len, u8 type,
+				  u8 *data, u8 data_len)
+{
+	eir[eir_len++] = sizeof(type) + data_len;
+	eir[eir_len++] = type;
+	memcpy(&eir[eir_len], data, data_len);
+	eir_len += data_len;
+
+	return eir_len;
+}
+
+static inline u16 eir_append_le16(u8 *eir, u16 eir_len, u8 type, u16 data)
+{
+	eir[eir_len++] = sizeof(type) + sizeof(data);
+	eir[eir_len++] = type;
+	put_unaligned_le16(data, &eir[eir_len]);
+	eir_len += sizeof(data);
+
+	return eir_len;
+}
+
+static inline u16 eir_skb_put_data(struct sk_buff *skb, u8 type, u8 *data, u8 data_len)
+{
+	u8 *eir;
+	u16 eir_len;
+
+	eir_len	= eir_precalc_len(data_len);
+	eir = skb_put(skb, eir_len);
+	WARN_ON(sizeof(type) + data_len > U8_MAX);
+	eir[0] = sizeof(type) + data_len;
+	eir[1] = type;
+	memcpy(&eir[2], data, data_len);
+
+	return eir_len;
+}
+
+static inline void *eir_get_data(u8 *eir, size_t eir_len, u8 type,
+				 size_t *data_len)
+{
+	size_t parsed = 0;
+
+	if (eir_len < 2)
+		return NULL;
+
+	while (parsed < eir_len - 1) {
+		u8 field_len = eir[0];
+
+		if (field_len == 0)
+			break;
+
+		parsed += field_len + 1;
+
+		if (parsed > eir_len)
+			break;
+
+		if (eir[1] != type) {
+			eir += field_len + 1;
+			continue;
+		}
+
+		/* Zero length data */
+		if (field_len == 1)
+			return NULL;
+
+		if (data_len)
+			*data_len = field_len - 1;
+
+		return &eir[2];
+	}
+
+	return NULL;
+}
+
+void *eir_get_service_data(u8 *eir, size_t eir_len, u16 uuid, size_t *len);