libcamera: ipa_module: Load IPA module signature

Load the signature from the .sign file, if available, when loading the
IPA module information and store it in the IPAModule class.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/libcamera/include/ipa_module.h

@@ -7,7 +7,9 @@
 #ifndef __LIBCAMERA_IPA_MODULE_H__
 #define __LIBCAMERA_IPA_MODULE_H__
 
+#include <stdint.h>
 #include <string>
+#include <vector>
 
 #include <ipa/ipa_interface.h>
 #include <ipa/ipa_module_info.h>
@@ -25,6 +27,7 @@ public:
 	bool isValid() const;
 
 	const struct IPAModuleInfo &info() const;
+	const std::vector<uint8_t> signature() const;
 	const std::string &path() const;
 
 	bool load();
@@ -38,6 +41,7 @@ public:
 
 private:
 	struct IPAModuleInfo info_;
+	std::vector<uint8_t> signature_;
 
 	std::string libPath_;
 	bool valid_;

src/libcamera/ipa_module.cpp

@@ -308,6 +308,20 @@ int IPAModule::loadIPAModuleInfo()
 		return -EINVAL;
 	}
 
+	/* Load the signature. Failures are not fatal. */
+	File sign{ libPath_ + ".sign" };
+	if (!sign.open(File::ReadOnly)) {
+		LOG(IPAModule, Debug)
+			<< "IPA module " << libPath_ << " is not signed";
+		return 0;
+	}
+
+	data = sign.map(0, -1, File::MapPrivate);
+	signature_.resize(data.size());
+	memcpy(signature_.data(), data.data(), data.size());
+
+	LOG(IPAModule, Debug) << "IPA module " << libPath_ << " is signed";
+
 	return 0;
 }
 
@@ -339,6 +353,21 @@ const struct IPAModuleInfo &IPAModule::info() const
 	return info_;
 }
 
+/**
+ * \brief Retrieve the IPA module signature
+ *
+ * The IPA module signature is stored alongside the IPA module in a file with a
+ * '.sign' suffix, and is loaded when the IPAModule instance is created. This
+ * function returns the signature without verifying it. If the signature is
+ * missing, the returned vector will be empty.
+ *
+ * \return The IPA module signature
+ */
+const std::vector<uint8_t> IPAModule::signature() const
+{
+	return signature_;
+}
+
 /**
  * \brief Retrieve the IPA module path
  *