EfiGuardDxe: delay driver unload when a non-Windows OS is booted

Mattiwatti · Mattiwatti · commit 9aff3669c670 · 2023-09-26T06:29:01.000+02:00
Fixes #91
diff --git a/EfiGuardDxe/EfiGuardDxe.c b/EfiGuardDxe/EfiGuardDxe.c
@@ -220,11 +220,6 @@ HookedLoadImage(
 								LoadedImage->ImageBase,
 								LoadedImage->ImageSize);
 			}
-			else
-			{
-				// A non-Windows OS is being booted. Unload ourselves
-				EfiGuardUnload(gImageHandle);
-			}
 		}
 	}
 
@@ -402,7 +397,7 @@ ExitBootServicesEvent(
 	// If the DSE bypass method is *not* DSE_DISABLE_SETVARIABLE_HOOK, perform some cleanup now. In principle this should allow
 	// linking with /SUBSYSTEM:EFI_BOOT_SERVICE_DRIVER, because our driver image may be freed after this callback returns.
 	// Using DSE_DISABLE_SETVARIABLE_HOOK requires linking with /SUBSYSTEM:EFI_RUNTIME_DRIVER, because the image must not be freed.
-	if (gDriverConfig.DseBypassMethod != DSE_DISABLE_SETVARIABLE_HOOK)
+	if (gDriverConfig.DseBypassMethod != DSE_DISABLE_SETVARIABLE_HOOK || gBootmgfwHandle == NULL)
 	{
 		// Uninstall our installed driver protocols
 		gBS->UninstallMultipleProtocolInterfaces(gImageHandle,

Original file line number	Diff line number	Diff line change
`@@ -220,11 +220,6 @@ HookedLoadImage(`
`220`	`220`	`LoadedImage->ImageBase,`
`221`	`221`	`LoadedImage->ImageSize);`
`222`	`222`	`}`
`223`		`- else`
`224`		`- {`
`225`		`- // A non-Windows OS is being booted. Unload ourselves`
`226`		`- EfiGuardUnload(gImageHandle);`
`227`		`- }`
`228`	`223`	`}`
`229`	`224`	`}`
`230`	`225`
`@@ -402,7 +397,7 @@ ExitBootServicesEvent(`
`402`	`397`	`// If the DSE bypass method is not DSE_DISABLE_SETVARIABLE_HOOK, perform some cleanup now. In principle this should allow`
`403`	`398`	`// linking with /SUBSYSTEM:EFI_BOOT_SERVICE_DRIVER, because our driver image may be freed after this callback returns.`
`404`	`399`	`// Using DSE_DISABLE_SETVARIABLE_HOOK requires linking with /SUBSYSTEM:EFI_RUNTIME_DRIVER, because the image must not be freed.`
`405`		`- if (gDriverConfig.DseBypassMethod != DSE_DISABLE_SETVARIABLE_HOOK)`
	`400`	`+ if (gDriverConfig.DseBypassMethod != DSE_DISABLE_SETVARIABLE_HOOK \|\| gBootmgfwHandle == NULL)`
`406`	`401`	`{`
`407`	`402`	`// Uninstall our installed driver protocols`
`408`	`403`	`gBS->UninstallMultipleProtocolInterfaces(gImageHandle,`