Verify payload length early on

I was looking at something else here and happened
to notce we didn't seem to be sanity
checking the length of strings in some places.

Looking harder, first thing I checked is a
really long filename in a dump file; that's
fine, we do check that.

Next I tried symlinks, and that caused a
an assertion trip process abort (thankfully at least)
deep in the bowels of the EROFS generation.

Fix this by checking the payload length against PATH_MAX.

Also:

- Add the missing error checking in mkcomposefs
- Add test infrastructure for "should fail" dumpfiles

Signed-off-by: Colin Walters <[email protected]>

libcomposefs/lcfs-writer.c

@@ -856,6 +856,11 @@ int lcfs_node_set_payload(struct lcfs_node_s *node, const char *payload)
 {
 	char *dup = NULL;
 	if (payload) {
+		const size_t len = strlen (payload);
+		if (len > PATH_MAX) {
+			errno = ENAMETOOLONG;
+			return -1;
+		}
 		dup = strdup(payload);
 		if (dup == NULL) {
 			errno = ENOMEM;

tests/Makefile.am

@@ -4,6 +4,7 @@ TEST_ASSETS_SMALL = \
 TEST_ASSETS_SMALL_EXTRA = \
 	special.dump.version special_v1.dump.version
 
+TEST_ASSETS_SHOULD_FAIL = should-fail-long-link.dump
 TEST_ASSETS = ${TEST_ASSETS_SMALL} \
 	cs9-x86_64-developer.dump.gz cs9-x86_64-minimal.dump.gz	\
 	f36-x86_64-silverblue.dump.gz
@@ -19,17 +20,22 @@ EXTRA_DIST = \
 	test-units.sh \
 	test-random-fuse.sh \
 	test-checksums.sh \
+	test-should-fail.sh \
 	integration.sh \
 	$(patsubst %,assets/%,${TEST_ASSETS_SMALL_EXTRA}) \
+	$(patsubst %,assets/%,${TEST_ASSETS_SHOULD_FAIL}) \
 	$(patsubst %,assets/%,${TEST_ASSETS_SMALL}) $(patsubst %,assets/%.sha256,${TEST_ASSETS_SMALL})
 
 check-checksums:
 	VALGRIND_PREFIX="${VALGRIND_PREFIX}" $(srcdir)/test-checksums.sh "$(builddir)/../tools/" "$(srcdir)/assets" "${TEST_ASSETS}"
 
+check-should-fail:
+	$(srcdir)/test-should-fail.sh ${TEST_ASSETS_SHOULD_FAIL}
+
 check-units:
 	VALGRIND_PREFIX="${VALGRIND_PREFIX}" $(srcdir)/test-units.sh "$(builddir)/../tools/"
 
 check-random-fuse:
 	VALGRIND_PREFIX="${VALGRIND_PREFIX}" $(srcdir)/test-random-fuse.sh "$(builddir)/../tools/"
 
-check: check-units check-checksums check-random-fuse
+check: check-units check-checksums check-random-fuse check-should-fail

tests/assets/should-fail-long-link.dump

@@ -0,0 +1,2 @@
+/ 4096 40555 2 0 0 0 1633950376.0 - - - -
+/link 5 120777 1 0 0 0 0.0 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa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- -

tests/meson.build

@@ -10,6 +10,10 @@ test_assets_small_extra = [
   'special_v1.dump.version',
 ]
 
+test_assets_sould_fail = [
+  'should-fail-long-link.dump'
+]
+
 test_assets = test_assets_small + [
   'cs9-x86_64-developer.dump.gz',
   'cs9-x86_64-minimal.dump.gz',
@@ -23,9 +27,13 @@ extra_dist = [
   'test-units.sh',
   'test-random-fuse.sh',
   'test-checksums.sh',
+  'test-should-fail.sh',
   'integration.sh',
 ]
 
+foreach asset : test_assets_should_fail
+  extra_dist += ['assets/' + asset]
+endforeach
 foreach asset : test_assets_small_extra
   extra_dist += ['assets/' + asset]
 endforeach

tests/test-checksums.sh

@@ -3,6 +3,7 @@
 BINDIR="$1"
 ASSET_DIR="$2"
 TEST_ASSETS="$3"
+TEST_ASSETS_SHOULD_FAIL="$4"
 
 . $(dirname $0)/test-lib.sh
 

tests/test-should-fail.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+cases=$1
+. $(dirname $0)/test-lib.sh
+
+set -e
+tmpfile=$(mktemp -d -t lcfs-test.XXXXXX)
+cd $tmpfile
+trap 'rm -rf -- "$tmpfile"' EXIT
+for f in $cases; do
+    if mkcomposefs --from-file $f >/dev/null 2>err.txt; then
+        fatal "Test case $f should have failed"
+    fi
+    echo "ok $f"
+done

tools/mkcomposefs.c

@@ -508,7 +508,8 @@ static char *tree_from_dump_line(dump_info *info, const char *line, size_t line_
 	lcfs_node_set_gid(node, gid);
 	lcfs_node_set_rdev(node, rdev);
 	lcfs_node_set_mtime(node, &mtime);
-	lcfs_node_set_payload(node, payload);
+	if (lcfs_node_set_payload(node, payload) < 0)
+		return make_error("Invalid payload");
 	if (content) {
 		ret = lcfs_node_set_content(node, (uint8_t *)content, size);
 		if (ret < 0)