From bd0656b5e2a57b0113d230c10866826d94301b5b Mon Sep 17 00:00:00 2001 From: Jiaxin Wu Date: Mon, 15 Aug 2016 10:34:49 +0800 Subject: MdeModulePkg: Fix potential failure if UseDefaultAddress configured IpSb->Reconfig should not be set to TRUE to focal the reconfiguration during the policy changes from Static to DHCP. It's redundancy because the default router table and default addresses have been freed ahead ( Detailed see Ip4Config2OnPolicyChanged() function). Otherwise, the potential failure will appear if UseDefaultAddress configured. Reproduce steps see below: #1. Set policy to DHCP. #2. If DHCP process is not complete yet, then run one APP to invoke UDP4 Configure with "UseDefaultAddress = TRUE" (loop to call UDP4 Configure until Ip4Mode.IsConfigured changes to TRUE). #3. Even DHCP succeed but Ip4Mode.IsConfigured flag never set to TRUE Concrete analysis is as follows: In #1, the policy will be set to DHCP, and then Ip4Config2OnPolicyChanged() will be called. In this function, if "IpSb->Reconfig" flag is set to TRUE, the original "IpSb->DefaultInterface" will be abandoned/freed once the DHCP process finished. In #2, UDP4 Configure with "UseDefaultAddress = TRUE" is called, that means the default interface (IpSb->DefaultInterface) will be selected as current instance's interface. In #3, when DHCP process finished, the original DefaultInterface will be abandoned/freed because "IpSb->Reconfig" flag is true. Meanwhile, one new interface is assigned to "IpSb->DefaultInterface". This new interface is different to the original one assigned to the UDP4 Configured instance. So, even DHCP process succeed, the up caller will never have the chance to get it's truly status. Cc: Cohen Eugene Cc: Ye Ting Cc: Fu Siyuan Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jiaxin Wu Tested-by: Eugene Cohen Reviewed-by: Ye Ting --- MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Config2Impl.c | 1 - 1 file changed, 1 deletion(-) (limited to 'MdeModulePkg') diff --git a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Config2Impl.c b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Config2Impl.c index f91a935634..75ad3011d0 100644 --- a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Config2Impl.c +++ b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Config2Impl.c @@ -150,7 +150,6 @@ Ip4Config2OnPolicyChanged ( // Start the dhcp configuration. // if (NewPolicy == Ip4Config2PolicyDhcp) { - IpSb->Reconfig = TRUE; Ip4StartAutoConfig (&IpSb->Ip4Config2Instance); } -- cgit v1.2.3