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, 60 insertions, 0 deletions

diff --git a/drivers/crypto/caam/dpseci-debugfs.c b/drivers/crypto/caam/dpseci-debugfs.c
new file mode 100644
index 000000000..020a9d8a8
--- /dev/null
+++ b/drivers/crypto/caam/dpseci-debugfs.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/* Copyright 2019 NXP */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/debugfs.h>
+#include "dpseci-debugfs.h"
+
+static int dpseci_dbg_fqs_show(struct seq_file *file, void *offset)
+{
+	struct dpaa2_caam_priv *priv = file->private;
+	u32 fqid, fcnt, bcnt;
+	int i, err;
+
+	seq_printf(file, "FQ stats for %s:\n", dev_name(priv->dev));
+	seq_printf(file, "%s%16s%16s\n",
+		   "Rx-VFQID",
+		   "Pending frames",
+		   "Pending bytes");
+
+	for (i = 0; i <  priv->num_pairs; i++) {
+		fqid = priv->rx_queue_attr[i].fqid;
+		err = dpaa2_io_query_fq_count(NULL, fqid, &fcnt, &bcnt);
+		if (err)
+			continue;
+
+		seq_printf(file, "%5d%16u%16u\n", fqid, fcnt, bcnt);
+	}
+
+	seq_printf(file, "%s%16s%16s\n",
+		   "Tx-VFQID",
+		   "Pending frames",
+		   "Pending bytes");
+
+	for (i = 0; i <  priv->num_pairs; i++) {
+		fqid = priv->tx_queue_attr[i].fqid;
+		err = dpaa2_io_query_fq_count(NULL, fqid, &fcnt, &bcnt);
+		if (err)
+			continue;
+
+		seq_printf(file, "%5d%16u%16u\n", fqid, fcnt, bcnt);
+	}
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(dpseci_dbg_fqs);
+
+void dpaa2_dpseci_debugfs_init(struct dpaa2_caam_priv *priv)
+{
+	priv->dfs_root = debugfs_create_dir(dev_name(priv->dev), NULL);
+
+	debugfs_create_file("fq_stats", 0444, priv->dfs_root, priv,
+			    &dpseci_dbg_fqs_fops);
+}
+
+void dpaa2_dpseci_debugfs_exit(struct dpaa2_caam_priv *priv)
+{
+	debugfs_remove_recursive(priv->dfs_root);
+}