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-rw-r--r--security/selinux/ss/context.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/security/selinux/ss/context.c b/security/selinux/ss/context.c
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index 000000000..38bc0aa52
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+++ b/security/selinux/ss/context.c
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Implementations of the security context functions.
+ *
+ * Author: Ondrej Mosnacek <omosnacek@gmail.com>
+ * Copyright (C) 2020 Red Hat, Inc.
+ */
+
+#include <linux/jhash.h>
+
+#include "context.h"
+#include "mls.h"
+
+u32 context_compute_hash(const struct context *c)
+{
+ u32 hash = 0;
+
+ /*
+ * If a context is invalid, it will always be represented by a
+ * context struct with only the len & str set (and vice versa)
+ * under a given policy. Since context structs from different
+ * policies should never meet, it is safe to hash valid and
+ * invalid contexts differently. The context_cmp() function
+ * already operates under the same assumption.
+ */
+ if (c->len)
+ return full_name_hash(NULL, c->str, c->len);
+
+ hash = jhash_3words(c->user, c->role, c->type, hash);
+ hash = mls_range_hash(&c->range, hash);
+ return hash;
+}