REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3709 REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3751
Currently, setups with variable policy operations used together with MM communicate from ArmPkg could fail with `EFI_INVALID_PARAMETER`. This was due to the errors from 2 following aspects: 1. For variable policy implementations in MdeModulePkg, the DXE runtime agent would communicate to MM to disable, register or query policies. However, during these operations, the MessageLength calculation is including MM communicate header. This could lead to MM agent read data across the given buffer boundary and/or trigger other errors. 2. On the other hand, current MM communicate routine from ArmPkg would fail the function if the input message length does not equal to input buffer size. As defined in PI specification, the `CommSize`, when as input, should stand for "The size of the data buffer being passed in", which would mean the maximal number of bytes `CommBuffer` can hold. In turn, the value of this input parameter can be used for MM handlers to determine whether the output data is too large to fit in this buffer. Enforcing the incoming buffer to hold exactly the number of used bytes mismatches with the PI spec description. This change fix MessageLength field calculation from variable policy and updated input argument inspections from MM communicate routine in ArmPkg to match PI spec descriptions. Patch v1 branch: https://github.com/kuqin12/edk2/tree/mm_communicate_check Cc: Jian J Wang <jian.j.w...@intel.com> Cc: Liming Gao <gaolim...@byosoft.com.cn> Cc: Hao A Wu <hao.a...@intel.com> Cc: Leif Lindholm <l...@nuviainc.com> Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org> Cc: Bret Barkelew <bret.barke...@microsoft.com> Cc: Michael Kubacki <michael.kuba...@microsoft.com> Kun Qin (2): MdeModulePkg: VariableSmmRuntimeDxe: Fix Variable Policy Message Length ArmPkg: MmCommunicationDxe: Update MM communicate input arguments checks ArmPkg/Drivers/MmCommunicationDxe/MmCommunication.c | 44 ++++++++++++-------- MdeModulePkg/Universal/Variable/RuntimeDxe/VariablePolicySmmDxe.c | 10 ++--- 2 files changed, 32 insertions(+), 22 deletions(-) -- 2.32.0.windows.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#84140): https://edk2.groups.io/g/devel/message/84140 Mute This Topic: https://groups.io/mt/87392593/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
