If none of the markers bears type information we can't just prepend a new
one. Otherwise two subsequent markers will begin at offset 0, blowing up
the chunk_len calculation a few lines after.
A particular case where this causes havoc is a string property in a tree
generated from "fs" input. A string property ends up with a TYPE_NULL
marker. Upon output, in write_propval(), we correctly guess it looks
like a TYPE_STRING. With the dummy marker prepended, We'd and up with two
markers:
{ type = TYPE_STRING, offset = 0 }
{ type = TYPE_NONE, offset = 0 }
The chunk_len for the fist marker will end up being calculated as 0.
This blows up later on because a zero-length string should never happen
because it lacks the terminating \0 (valgrind catches this).
I'm also adding an assertion to write_propval_string() so that such
cases won't go unnoticed in future and a test case.
Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
---
tests/run_tests.sh | 14 ++++++++++++++
treesource.c | 3 ++-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 0e9f345..f8cc481 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -137,6 +137,19 @@ check_align () {
)
}
+# $1: first file
+# $2: second file
+files_equal () {
+ shorten_echo "files_equal $@: "
+ (
+ if diff -q $1 $2; then
+ PASS
+ else
+ FAIL "File $1 differs from $2"
+ fi
+ )
+}
+
run_dtc_test () {
printf "dtc $*: "
base_run_test wrap_test $VALGRIND $DTC "$@"
@@ -460,6 +473,7 @@ libfdt_tests () {
run_dtc_test -I fs -O dts -o fs.test_tree1.test.dts $FSBASE/test_tree1
run_dtc_test -I fs -O dtb -o fs.test_tree1.test.dtb $FSBASE/test_tree1
run_test dtbs_equal_unordered -m fs.test_tree1.test.dtb test_tree1.dtb
+ base_run_test files_equal fs_tree1.dts fs.test_tree1.test.dts
# check full tests
for good in test_tree1.dtb; do
diff --git a/treesource.c b/treesource.c
index c1fdb86..eabb929 100644
--- a/treesource.c
+++ b/treesource.c
@@ -64,6 +64,7 @@ static bool isstring(char c)
static void write_propval_string(FILE *f, const char *s, size_t len)
{
const char *end = s + len - 1;
+ assert(len > 0);
assert(*end == '\0');
fprintf(f, "\"");
@@ -221,7 +222,7 @@ static void write_propval(FILE *f, struct property *prop)
if (!next_type_marker(m)) {
/* data type information missing, need to guess */
dummy_marker.type = guess_value_type(prop);
- dummy_marker.next = prop->val.markers;
+ dummy_marker.next = NULL;
dummy_marker.offset = 0;
dummy_marker.ref = NULL;
m = &dummy_marker;
--
2.19.0
