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niruiyu
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Nov 23, 2023
Root cause: 1. Before DisableReadonlyPageWriteProtect() is called, the return address (#1) is pushed in shadow stack. 2. CET is disabled. 3. DisableReadonlyPageWriteProtect() returns to #1. 4. Page table is modified. 5. EnableReadonlyPageWriteProtect() is called, but the return address (#2) is not pushed in shadow stack. 6. CET is enabled. 7. EnableReadonlyPageWriteProtect() returns to #2. #CP exception happens because the actual return address (#2) doesn't match the return address stored in shadow stack (#1). Analysis: Shadow stack will stop update after CET disable (DisableCet() in DisableReadOnlyPageWriteProtect), but normal smi stack will be continue updated with the function called and return (DisableReadOnlyPageWriteProtect & EnableReadOnlyPageWriteProtect), thus leading stack mismatch after CET re-enabled (EnableCet() in EnableReadOnlyPageWriteProtect). According SDM Vol 3, 6.15-Control Protection Exception: Normal smi stack and shadow stack must be matched when CET enable, otherwise CP Exception will happen, which is caused by a near RET instruction. CET is disabled in DisableCet(), while can be enabled in EnableCet(). This way won't cause the problem because they are implemented in a way that return address of DisableCet() is poped out from shadow stack (Incsspq performs a pop to increases the shadow stack) and EnableCet() doesn't use "RET" but "JMP" to return to caller. So calling EnableCet() and DisableCet() doesn't have the same issue as calling DisableReadonlyPageWriteProtect() and EnableReadonlyPageWriteProtect(). With above root cause & analysis, define below 2 macros instead of functions for WP & CET operation: WRITE_UNPROTECT_RO_PAGES (Wp, Cet) WRITE_PROTECT_RO_PAGES (Wp, Cet) Because DisableCet() & EnableCet() must be in the same function to avoid shadow stack and normal SMI stack mismatch. Note: WRITE_UNPROTECT_RO_PAGES () must be called pair with WRITE_PROTECT_RO_PAGES () in same function. Change-Id: I4e126697efcd8dbfb4887da034d8691bfca969e3 Cc: Eric Dong <eric.dong@intel.com> Cc: Ray Ni <ray.ni@intel.com> Cc: Zeng Star <star.zeng@intel.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Rahul Kumar <rahul1.kumar@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Ray Ni <ray.ni@intel.com> Reviewed-by: Eric Dong <eric.dong@intel.com>
niruiyu
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Apr 10, 2024
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=4535 Bug Details: PixieFail Bug #2 CVE-2023-45230 CVSS 8.3 : CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer Changes Overview: > -UINT8 * > +EFI_STATUS > Dhcp6AppendOption ( > - IN OUT UINT8 *Buf, > - IN UINT16 OptType, > - IN UINT16 OptLen, > - IN UINT8 *Data > + IN OUT EFI_DHCP6_PACKET *Packet, > + IN OUT UINT8 **PacketCursor, > + IN UINT16 OptType, > + IN UINT16 OptLen, > + IN UINT8 *Data > ); Dhcp6AppendOption() and variants can return errors now. All callsites are adapted accordingly. It gets passed in EFI_DHCP6_PACKET as additional parameter ... > + // > + // Verify the PacketCursor is within the packet > + // > + if ( (*PacketCursor < Packet->Dhcp6.Option) > + || (*PacketCursor >= Packet->Dhcp6.Option + (Packet->Size - sizeof (EFI_DHCP6_HEADER)))) > + { > + return EFI_INVALID_PARAMETER; > + } ... so it can look at Packet->Size when checking buffer space. Also to allow Packet->Length updates. Lots of checks added. Cc: Saloni Kasbekar <saloni.kasbekar@intel.com> Cc: Zachary Clark-williams <zachary.clark-williams@intel.com> Signed-off-by: Doug Flick [MSFT] <doug.edk2@gmail.com> Reviewed-by: Saloni Kasbekar <saloni.kasbekar@intel.com>
niruiyu
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Nov 14, 2024
This patch does not impact functionality. It aims to clarify the synchronization flow between the BSP and APs to enhance code readability and understanding: Steps tianocore#6 and tianocore#11 are the basic synchronization requirements for all cases. Steps #1 is additional requirements if the MmCpuSyncModeTradition mode is selected. Steps #1, #2, #3, tianocore#4, tianocore#5, tianocore#7, tianocore#8, tianocore#9, and tianocore#10 are additional requirements if the system needs to configure the MTRR. Steps tianocore#9 and tianocore#10 are additional requirements if the system needs to support the mSmmDebugAgentSupport. Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
niruiyu
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Nov 14, 2024
… func This patch is for PiSmmCpuDxeSmm driver to add one round wait/release sync for BSP and AP to perform the SMM CPU Platform Hook before executing MMI Handler: SmmCpuPlatformHookBeforeMmiHandler (). With the function, SMM CPU driver can perform the platform specific items after one round BSP and AP sync (to make sure all APs in SMI) and before the MMI handlers. After the change, steps #1 and #2 are additional requirements if the MmCpuSyncModeTradition mode is selected. Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
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