Add a command in delta_generator to calculate the maximum signature size
The ota generation script used to call openssl functions to get the
signature size. This is no longer viable for EC keys. So we add this new
functionality here in the delta_generator. Because the signature size
will be later used by the delta_generator to sign the payload.
Bug: 141244025
Test: call the binary with new option
Change-Id: Id743325242faf7a2b2dcec5e218219dba12a8e88
diff --git a/payload_generator/generate_delta_main.cc b/payload_generator/generate_delta_main.cc
index 1323534..f035ff1 100644
--- a/payload_generator/generate_delta_main.cc
+++ b/payload_generator/generate_delta_main.cc
@@ -423,6 +423,10 @@
DEFINE_bool(disable_fec_computation,
false,
"Disables the fec data computation on device.");
+ DEFINE_string(
+ out_maximum_signature_size_file,
+ "",
+ "Path to the output maximum signature size given a private key.");
brillo::FlagHelper::Init(
argc,
@@ -444,6 +448,30 @@
// Initialize the Xz compressor.
XzCompressInit();
+ if (!FLAGS_out_maximum_signature_size_file.empty()) {
+ LOG_IF(FATAL, FLAGS_private_key.empty())
+ << "Private key is not provided when calculating the maximum signature "
+ "size.";
+
+ size_t maximum_signature_size;
+ if (!PayloadSigner::GetMaximumSignatureSize(FLAGS_private_key,
+ &maximum_signature_size)) {
+ LOG(ERROR) << "Failed to get the maximum signature size of private key: "
+ << FLAGS_private_key;
+ return 1;
+ }
+ // Write the size string to output file.
+ string signature_size_string = std::to_string(maximum_signature_size);
+ if (!utils::WriteFile(FLAGS_out_maximum_signature_size_file.c_str(),
+ signature_size_string.c_str(),
+ signature_size_string.size())) {
+ PLOG(ERROR) << "Failed to write the maximum signature size to "
+ << FLAGS_out_maximum_signature_size_file << ".";
+ return 1;
+ }
+ return 0;
+ }
+
vector<size_t> signature_sizes;
if (!FLAGS_signature_size.empty()) {
ParseSignatureSizes(FLAGS_signature_size, &signature_sizes);