dtc/tests/get_alias.c
Pierre-Clément Tosi 79b9e326a1 libfdt: fdt_get_alias_namelen: Validate aliases
Ensure that the alias found matches the device tree specification v0.4:

    Each property of the /aliases node defines an alias. The property
    name specifies the alias name. The property value specifies the full
    path to a node in the devicetree.

This protects against a stack overflow caused by

    fdt_path_offset_namelen(fdt, path, namelen)

calling

    fdt_path_offset(fdt, fdt_get_alias_namelen(fdt, path, namelen))

leading to infinite recursion on DTs with "circular" aliases.

This fix was originally written by Mike McTernan for Android in [1].

[1]: https://android.googlesource.com/platform/external/dtc/+/9308e7f9772bd226fea9925b1fc4d53c127ed4d5

Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
Acked-by: Mike McTernan <mikemcternan@google.com>
Message-ID: <20231010092725.63h7c45p2fnmj577@google.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2023-10-11 11:35:08 +11:00

56 lines
1.2 KiB
C

// SPDX-License-Identifier: LGPL-2.1-or-later
/*
* libfdt - Flat Device Tree manipulation
* Testcase for fdt_get_alias()
* Copyright (C) 2006 David Gibson, IBM Corporation.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <libfdt.h>
#include "tests.h"
#include "testdata.h"
static void check_alias(void *fdt, const char *path, const char *alias)
{
const char *aliaspath;
aliaspath = fdt_get_alias(fdt, alias);
if (!path && !aliaspath)
return;
if (!aliaspath)
FAIL("fdt_get_alias(%s) failed\n", alias);
if (!path)
FAIL("fdt_get_alias(%s) returned %s instead of NULL",
alias, aliaspath);
if (strcmp(aliaspath, path) != 0)
FAIL("fdt_get_alias(%s) returned %s instead of %s\n",
alias, aliaspath, path);
}
int main(int argc, char *argv[])
{
void *fdt;
test_init(argc, argv);
fdt = load_blob_arg(argc, argv);
check_alias(fdt, NULL, "empty");
check_alias(fdt, NULL, "nonull");
check_alias(fdt, NULL, "relative");
check_alias(fdt, "/subnode@1", "s1");
check_alias(fdt, "/subnode@1/subsubnode", "ss1");
check_alias(fdt, "/subnode@1/subsubnode/subsubsubnode", "sss1");
check_alias(fdt, NULL, "loop"); // Might trigger a stack overflow
PASS();
}