linux-kernel - Re: [PATCH] Modify UEFI anti-bricking code

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 06 Jun 2013 15:40:26 +0800
From:	joeyli <jlee@...e.com>
To:	Matthew Garrett <matthew.garrett@...ula.com>
Cc:	Matt Fleming <matt@...sole-pimps.org>,
	"Fleming, Matt" <matt.fleming@...el.com>,
	"rja@....com" <rja@....com>, "mingo@...nel.org" <mingo@...nel.org>,
	"torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>,
	"bp@...en8.de" <bp@...en8.de>, "jkosina@...e.cz" <jkosina@...e.cz>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"hpa@...ux.intel.com" <hpa@...ux.intel.com>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"oneukum@...e.de" <oneukum@...e.de>
Subject: Re: [PATCH] Modify UEFI anti-bricking code

於 四，2013-06-06 於 05:42 +0000，Matthew Garrett 提到：
> On Thu, 2013-06-06 at 13:05 +0800, joeyli wrote:
> 
> > +		if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
> > +			return EFI_OUT_OF_RESOURCES;
> 
> I'd move this up to the top of the function, and just return 0 - there's
> no risk of the firmware causing problems if it's a volatile variable, so
> we should probably just pass it down to the firmware and return an error
> from there.
> 

OK, I moved volatile checking to the top of the function.
New version, version 3 diff result like the following.


Thanks a lot for reviewing
Joey Lee

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index cc3cfe8..5ae2eb0 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -53,6 +53,8 @@
 
 #define EFI_DEBUG	1
 
+#define EFI_MIN_RESERVE 5120
+
 #define EFI_DUMMY_GUID \
 	EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)
 
@@ -988,7 +990,11 @@ void __init efi_enter_virtual_mode(void)
 	kfree(new_memmap);
 
 	/* clean DUMMY object */
-	efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID, 0, 0, NULL);
+	efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+			 EFI_VARIABLE_NON_VOLATILE |
+			 EFI_VARIABLE_BOOTSERVICE_ACCESS |
+			 EFI_VARIABLE_RUNTIME_ACCESS,
+			 0, NULL);
 }
 
 /*
@@ -1040,6 +1046,9 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 	efi_status_t status;
 	u64 storage_size, remaining_size, max_size;
 
+	if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
+		return 0;
+
 	status = efi.query_variable_info(attributes, &storage_size,
 					 &remaining_size, &max_size);
 	if (status != EFI_SUCCESS)
@@ -1051,7 +1060,9 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 	 * write if permitting it would reduce the available space to under
 	 * 5KB. This figure was provided by Samsung, so should be safe.
 	 */
-	if ((remaining_size - size < 5120) && !efi_no_storage_paranoia) {
+	if ((remaining_size - size < EFI_MIN_RESERVE) &&
+		!efi_no_storage_paranoia) {
+
 		/*
 		 * Triggering garbage collection may require that the firmware
 		 * generate a real EFI_OUT_OF_RESOURCES error. We can force
@@ -1061,7 +1072,10 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 		void *dummy = kmalloc(dummy_size, GFP_ATOMIC);
 
 		status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
-					  attributes, dummy_size, dummy);
+					  EFI_VARIABLE_NON_VOLATILE |
+					  EFI_VARIABLE_BOOTSERVICE_ACCESS |
+					  EFI_VARIABLE_RUNTIME_ACCESS,
+					  dummy_size, dummy);
 
 		if (status == EFI_SUCCESS) {
 			/*
@@ -1069,7 +1083,10 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 			 * that we delete it...
 			 */
 			efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
-					 attributes, 0, dummy);
+					 EFI_VARIABLE_NON_VOLATILE |
+					 EFI_VARIABLE_BOOTSERVICE_ACCESS |
+					 EFI_VARIABLE_RUNTIME_ACCESS,
+					 0, dummy);
 		}
 
 		/*
@@ -1085,7 +1102,7 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 		/*
 		 * There still isn't enough room, so return an error
 		 */
-		if (remaining_size - size < 5120)
+		if (remaining_size - size < EFI_MIN_RESERVE)
 			return EFI_OUT_OF_RESOURCES;
 	}
 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/