libcamera: ipa_manager: Verify IPA module signature

Decide whether to isolate the IPA module using the module signature
instead of its license.

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

src/libcamera/include/ipa_manager.h

@@ -38,6 +38,8 @@ private:
 		      std::vector<std::string> &files);
 	unsigned int addDir(const char *libDir, unsigned int maxDepth = 0);
 
+	bool isSignatureValid(IPAModule *ipa) const;
+
 	static const uint8_t publicKeyData_[];
 	static const PubKey pubKey_;
 };

src/libcamera/include/ipa_module.h

@@ -37,8 +37,6 @@ public:
 	bool match(PipelineHandler *pipe,
 		   uint32_t minVersion, uint32_t maxVersion) const;
 
-	bool isOpenSource() const;
-
 private:
 	struct IPAModuleInfo info_;
 	std::vector<uint8_t> signature_;

src/libcamera/ipa_manager.cpp

@@ -12,6 +12,7 @@
 #include <string.h>
 #include <sys/types.h>
 
+#include "file.h"
 #include "ipa_module.h"
 #include "ipa_proxy.h"
 #include "log.h"
@@ -271,12 +272,12 @@ std::unique_ptr<IPAInterface> IPAManager::createIPA(PipelineHandler *pipe,
 		return nullptr;
 
 	/*
-	 * Load and run the IPA module in a thread if it is open-source, or
+	 * Load and run the IPA module in a thread if it has a valid signature,
-	 * isolate it in a separate process otherwise.
+	 * or isolate it in a separate process otherwise.
 	 *
 	 * \todo Implement a better proxy selection
 	 */
-	const char *proxyName = m->isOpenSource()
+	const char *proxyName = isSignatureValid(m)
 			      ? "IPAProxyThread" : "IPAProxyLinux";
 	IPAProxyFactory *pf = nullptr;
 
@@ -301,4 +302,23 @@ std::unique_ptr<IPAInterface> IPAManager::createIPA(PipelineHandler *pipe,
 	return proxy;
 }
 
+bool IPAManager::isSignatureValid(IPAModule *ipa) const
+{
+	File file{ ipa->path() };
+	if (!file.open(File::ReadOnly))
+		return false;
+
+	Span<uint8_t> data = file.map();
+	if (data.empty())
+		return false;
+
+	bool valid = pubKey_.verify(data, ipa->signature());
+
+	LOG(IPAManager, Debug)
+		<< "IPA module " << ipa->path() << " signature is "
+		<< (valid ? "valid" : "not valid");
+
+	return valid;
+}
+
 } /* namespace libcamera */

src/libcamera/ipa_module.cpp

@@ -472,29 +472,4 @@ bool IPAModule::match(PipelineHandler *pipe,
 	       !strcmp(info_.pipelineName, pipe->name());
 }
 
-/**
- * \brief Verify if the IPA module is open source
- *
- * \sa IPAModuleInfo::license
- */
-bool IPAModule::isOpenSource() const
-{
-	static const char *osLicenses[] = {
-		"GPL-2.0-only",
-		"GPL-2.0-or-later",
-		"GPL-3.0-only",
-		"GPL-3.0-or-later",
-		"LGPL-2.1-only",
-		"LGPL-2.1-or-later",
-		"LGPL-3.0-only",
-		"LGPL-3.0-or-later",
-	};
-
-	for (unsigned int i = 0; i < ARRAY_SIZE(osLicenses); i++)
-		if (!strcmp(osLicenses[i], info_.license))
-			return true;
-
-	return false;
-}
-
 } /* namespace libcamera */