File ipxe-efi-fix-garbage-bytes-in-device-path.patch of Package qemu

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File ipxe-efi-fix-garbage-bytes-in-device-path.patch of Package qemu (Revision dccf5c8b7c3f27a600daf4aabf3000d9)

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From 632e57f0f36d9b48f574db273a19e26bf592fc99 Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@ipxe.org>
Date: Wed, 22 Jun 2016 09:07:20 +0100
Subject: [PATCH] [efi] Do not copy garbage bytes into SNP device path MAC
 address

The SNP device path includes the network device's MAC address within
the MAC_ADDR_DEVICE_PATH.MacAddress field.  We check that the
link-layer address will fit within this field, and then perform the
copy using the length of the destination buffer.

At 32 bytes, the MacAddress field is actually larger than the current
maximum iPXE link-layer address.  The copy therefore overflows the
source buffer, resulting in trailing garbage bytes being appended to
the device path's MacAddress.  This is invisible in debug messages,
since the DevicePathToText protocol will render only the length
implied by the interface type.

Fix by copying only the actual length of the link-layer address (which
we have already verified will not overflow the destination buffer).

Debugged-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/interface/efi/efi_snp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: ipxe/src/interface/efi/efi_snp.c
===================================================================
--- ipxe.orig/src/interface/efi/efi_snp.c
+++ ipxe/src/interface/efi/efi_snp.c
@@ -1049,7 +1049,7 @@ static int efi_snp_probe ( struct net_de
 	macpath->Header.SubType = MSG_MAC_ADDR_DP;
 	macpath->Header.Length[0] = sizeof ( *macpath );
 	memcpy ( &macpath->MacAddress, netdev->ll_addr,
-		 sizeof ( macpath->MacAddress ) );
+		 netdev->ll_protocol->ll_addr_len );
 	macpath->IfType = ntohs ( netdev->ll_protocol->ll_proto );
 	memset ( path_end, 0, sizeof ( *path_end ) );
 	path_end->Type = END_DEVICE_PATH_TYPE;

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File ipxe-efi-fix-garbage-bytes-in-device-path.patch of Package qemu (Revision dccf5c8b7c3f27a600daf4aabf3000d9)

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