From 9d9c795cd721bd11f4a8cc039e5553c83bd66fdf Mon Sep 17 00:00:00 2001 From: David Gibson Date: Sun, 18 Mar 2018 00:12:12 +1100 Subject: libfdt: Add fdt_check_full() function 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 --- libfdt/fdt_ro.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 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, 141 insertions(+), 1 deletion(-) create mode 100644 tests/check_full.c diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c index c74b962..4ba7c93 100644 --- a/libfdt/fdt_ro.c +++ b/libfdt/fdt_ro.c @@ -857,3 +857,66 @@ 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; + const void *prop; + const char *propname; + + 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: + prop = fdt_getprop_by_offset(fdt, offset, &propname, + &err); + if (!prop) + return err; + 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 ea437ca..d423570 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 489886f..2c2c4fd 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 +#include +#include +#include + +#include + +#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] ", 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"); + 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 f80029a..2215e8a 100755 --- a/tests/run_tests.sh +++ b/tests/run_tests.sh @@ -445,6 +445,15 @@ libfdt_tests () { run_wrap_error_test $DTC -I dtb -O dts -o /dev/null ovf_size_strings.dtb 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 () { -- cgit v1.2.1