On 26/3/18 10:25 am, David Gibson wrote:
> This new function implements a complete and thorough check of an fdt blob's
> structure. Given a buffer containing an fdt, it should return 0 only if
> the fdt within is structurally sound in all regards. It doesn't check
> anything about the blob's contents (i.e. the actual values of the nodes and
> properties), of course.
>
> Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> libfdt/fdt_ro.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++
> libfdt/libfdt.h | 2 ++
> tests/.gitignore | 1 +
> tests/Makefile.tests | 2 +-
> tests/check_full.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> tests/dumptrees.c | 2 ++
> tests/run_tests.sh | 9 ++++++++
> 7 files changed, 135 insertions(+), 1 deletion(-)
> create mode 100644 tests/check_full.c
>
> diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
> index c74b962..4dbd0c5 100644
> --- a/libfdt/fdt_ro.c
> +++ b/libfdt/fdt_ro.c
> @@ -857,3 +857,60 @@ int fdt_node_offset_by_compatible(const void *fdt, int startoffset,
>
> return offset; /* error from fdt_next_node() */
> }
> +
> +int fdt_check_full(const void *fdt, size_t bufsize)
> +{
> + int err;
> + int num_memrsv;
> + int offset, nextoffset = 0;
> + uint32_t tag;
> + unsigned depth = 0;
> +
> + if (bufsize < FDT_V1_SIZE)
> + return -FDT_ERR_TRUNCATED;
> + err = fdt_check_header(fdt);
> + if (err != 0)
> + return err;
> + if (bufsize < fdt_totalsize(fdt))
> + return -FDT_ERR_TRUNCATED;
> +
> + num_memrsv = fdt_num_mem_rsv(fdt);
> + if (num_memrsv < 0)
> + return num_memrsv;
> +
> + while (1) {
> + offset = nextoffset;
> + tag = fdt_next_tag(fdt, offset, &nextoffset);
> +
> + if (nextoffset < 0)
> + return nextoffset;
> +
> + switch (tag) {
> + case FDT_NOP:
> + break;
> +
> + case FDT_END:
> + if (depth != 0)
> + return -FDT_ERR_BADSTRUCTURE;
> + return 0;
> +
> + case FDT_BEGIN_NODE:
> + depth++;
> + if (depth > INT_MAX)
> + return -FDT_ERR_BADSTRUCTURE;
> + break;
> +
> + case FDT_END_NODE:
> + if (depth == 0)
> + return -FDT_ERR_BADSTRUCTURE;
> + depth--;
> + break;
> +
> + case FDT_PROP:
> + break;
> +
> + default:
> + return -FDT_ERR_INTERNAL;
> + }
> + }
> +}
> diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
> index 9938fb8..f044298 100644
> --- a/libfdt/libfdt.h
> +++ b/libfdt/libfdt.h
> @@ -295,6 +295,8 @@ int fdt_move(const void *fdt, void *buf, int bufsize);
> /* Read-only functions */
> /**********************************************************************/
>
> +int fdt_check_full(const void *fdt, size_t bufsize);
> +
> /**
> * fdt_get_string - retrieve a string from the strings block of a device tree
> * @fdt: pointer to the device tree blob
> diff --git a/tests/.gitignore b/tests/.gitignore
> index 60bbb09..9fce43a 100644
> --- a/tests/.gitignore
> +++ b/tests/.gitignore
> @@ -8,6 +8,7 @@ tmp.*
> /asm_tree_dump
> /boot-cpuid
> /char_literal
> +/check_full
> /check_header
> /check_path
> /del_node
> diff --git a/tests/Makefile.tests b/tests/Makefile.tests
> index fc1b160..b73a19a 100644
> --- a/tests/Makefile.tests
> +++ b/tests/Makefile.tests
> @@ -26,7 +26,7 @@ LIB_TESTS_L = get_mem_rsv \
> property_iterate \
> subnode_iterate \
> overlay overlay_bad_fixup \
> - check_path check_header
> + check_path check_header check_full
> LIB_TESTS = $(LIB_TESTS_L:%=$(TESTS_PREFIX)%)
>
> LIBTREE_TESTS_L = truncated_property truncated_string truncated_memrsv
> diff --git a/tests/check_full.c b/tests/check_full.c
> new file mode 100644
> index 0000000..04c0bc1
> --- /dev/null
> +++ b/tests/check_full.c
> @@ -0,0 +1,63 @@
> +/*
> + * libfdt - Flat Device Tree manipulation
> + * Tests if two given dtbs are structurally equal (including order)
> + * Copyright (C) 2007 David Gibson, IBM Corporation.
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public License
> + * as published by the Free Software Foundation; either version 2.1 of
> + * the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <stdint.h>
> +
> +#include <libfdt.h>
> +
> +#include "tests.h"
> +#include "testdata.h"
> +
> +static int expect_bad; /* = 0 */
> +
> +int main(int argc, char *argv[])
> +{
> + const char *filename;
> + char *fdt;
> + size_t len;
> + int err;
> +
> + test_init(argc, argv);
> + if ((argc != 2)
> + && ((argc != 3) || !streq(argv[1], "-n")))
> + CONFIG("Usage: %s [-n] <dtb file>", argv[0]);
> + if (argc == 3)
> + expect_bad = 1;
> +
> + filename = argv[argc-1];
> + err = utilfdt_read_err(filename, &fdt, &len);
> + if (err)
> + CONFIG("Couldn't open blob from \"%s\": %s",
> + filename, strerror(err));
> +
> + vg_prepare_blob(fdt, len);
> +
> + err = fdt_check_full(fdt, len);
> +
> + if (expect_bad && (err == 0))
> + FAIL("fdt_check_full() succeeded unexpectedly");
check_full -n truncated_string.dtb: FAIL fdt_check_full() succeeded
unexpectedly
Fails on both ppc64be and x86.
> + else if (!expect_bad && (err != 0))
> + FAIL("fdt_check_full() failed: %s", fdt_strerror(err));
> +
> + PASS();
> +}
> diff --git a/tests/dumptrees.c b/tests/dumptrees.c
> index 87d1c3d..ff5818d 100644
> --- a/tests/dumptrees.c
> +++ b/tests/dumptrees.c
> @@ -37,6 +37,8 @@ static struct {
> TREE(test_tree1),
> TREE(bad_node_char), TREE(bad_node_format), TREE(bad_prop_char),
> TREE(ovf_size_strings),
> + TREE(truncated_property), TREE(truncated_string),
> + TREE(truncated_memrsv),
> };
>
> #define NUM_TREES (sizeof(trees) / sizeof(trees[0]))
> diff --git a/tests/run_tests.sh b/tests/run_tests.sh
> index ee5a43a..615b86d 100755
> --- a/tests/run_tests.sh
> +++ b/tests/run_tests.sh
> @@ -445,6 +445,15 @@ libfdt_tests () {
>
> # Check header tests
> run_test check_header test_tree1.dtb
> +
> + # check full tests
> + for good in test_tree1.dtb; do
> + run_test check_full $good
> + done
> + for bad in truncated_property.dtb truncated_string.dtb \
> + truncated_memrsv.dtb; do
> + run_test check_full -n $bad
> + done
> }
>
> dtc_tests () {
>
--
Alexey
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