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, 71 insertions, 0 deletions

diff --git a/security/selinux/include/audit.h b/security/selinux/include/audit.h
new file mode 100644
index 000000000..85a531ac7
--- /dev/null
+++ b/security/selinux/include/audit.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * SELinux support for the Audit LSM hooks
+ *
+ * Author: James Morris <jmorris@redhat.com>
+ *
+ * Copyright (C) 2005 Red Hat, Inc., James Morris <jmorris@redhat.com>
+ * Copyright (C) 2006 Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
+ * Copyright (C) 2006 IBM Corporation, Timothy R. Chavez <tinytim@us.ibm.com>
+ */
+
+#ifndef _SELINUX_AUDIT_H
+#define _SELINUX_AUDIT_H
+
+#include <linux/audit.h>
+#include <linux/types.h>
+
+/**
+ * selinux_audit_rule_avc_callback - update the audit LSM rules on AVC events.
+ * @event: the AVC event
+ *
+ * Update any audit LSM rules based on the AVC event specified in @event.
+ * Returns 0 on success, negative values otherwise.
+ */
+int selinux_audit_rule_avc_callback(u32 event);
+
+/**
+ * selinux_audit_rule_init - alloc/init an selinux audit rule structure.
+ * @field: the field this rule refers to
+ * @op: the operator the rule uses
+ * @rulestr: the text "target" of the rule
+ * @rule: pointer to the new rule structure returned via this
+ * @gfp: GFP flag used for kmalloc
+ *
+ * Returns 0 if successful, -errno if not.  On success, the rule structure
+ * will be allocated internally.  The caller must free this structure with
+ * selinux_audit_rule_free() after use.
+ */
+int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **rule,
+			    gfp_t gfp);
+
+/**
+ * selinux_audit_rule_free - free an selinux audit rule structure.
+ * @rule: pointer to the audit rule to be freed
+ *
+ * This will free all memory associated with the given rule.
+ * If @rule is NULL, no operation is performed.
+ */
+void selinux_audit_rule_free(void *rule);
+
+/**
+ * selinux_audit_rule_match - determine if a context ID matches a rule.
+ * @prop: includes the context ID to check
+ * @field: the field this rule refers to
+ * @op: the operator the rule uses
+ * @rule: pointer to the audit rule to check against
+ *
+ * Returns 1 if the context id matches the rule, 0 if it does not, and
+ * -errno on failure.
+ */
+int selinux_audit_rule_match(struct lsm_prop *prop, u32 field, u32 op,
+			     void *rule);
+
+/**
+ * selinux_audit_rule_known - check to see if rule contains selinux fields.
+ * @rule: rule to be checked
+ * Returns 1 if there are selinux fields specified in the rule, 0 otherwise.
+ */
+int selinux_audit_rule_known(struct audit_krule *rule);
+
+#endif /* _SELINUX_AUDIT_H */