tests: add fuzz-bcd

src/boot/efi/fuzz-bcd.c

@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fuzz.h"
+#include "utf8.h"
+
+#include "bcd.c"
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+        _cleanup_free_ void *p = NULL;
+
+        /* This limit was borrowed from src/boot/efi/boot.c */
+        if (size > 100*1024)
+                return 0;
+
+        if (!getenv("SYSTEMD_LOG_LEVEL"))
+                log_set_max_level(LOG_CRIT);
+
+        p = memdup(data, size);
+        assert_se(p);
+
+        char16_t *title = get_bcd_title(p, size);
+        assert_se(!title || char16_strlen(title) >= 0);
+        return 0;
+}

src/boot/efi/meson.build

@@ -360,6 +360,9 @@ if efi_arch[1] in ['ia32', 'x86_64', 'arm', 'aarch64']
                  [],
                  'HAVE_ZSTD'],
         ]
+        fuzzers += [
+                [['src/boot/efi/fuzz-bcd.c']],
+        ]
 endif
 
 systemd_boot_objects = []

tools/oss-fuzz.sh

@@ -36,6 +36,13 @@ else
     apt-get install -y gperf m4 gettext python3-pip \
         libcap-dev libmount-dev libkmod-dev \
         pkg-config wget python3-jinja2
+
+    # gnu-efi is installed here to enable -Dgnu-efi behind which fuzz-bcd
+    # is hidden. It isn't linked against efi. It doesn't
+    # even include "efi.h" because "bcd.c" can work in "unit test" mode
+    # where it isn't necessary.
+    apt-get install -y gnu-efi zstd
+
     pip3 install -r .github/workflows/requirements.txt --require-hashes
 
     # https://github.com/google/oss-fuzz/issues/6868
@@ -56,6 +63,15 @@ fi
 
 ninja -v -C "$build" fuzzers
 
+# Compressed BCD files are kept in test/test-bcd so let's unpack them
+# and put them all in the seed corpus.
+bcd=$(mktemp -d)
+for i in test/test-bcd/*.zst; do
+     unzstd "$i" -o "$bcd/$(basename "${i%.zst}")";
+done
+zip -jqr "$OUT/fuzz-bcd_seed_corpus.zip" "$bcd"
+rm -rf "$bcd"
+
 # The seed corpus is a separate flat archive for each fuzzer,
 # with a fixed name ${fuzzer}_seed_corpus.zip.
 for d in "$(dirname "$0")/../test/fuzz/fuzz-"*; do