Correct and simplify page locking
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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parent
3d84bddcc0
commit
88bde5b28e
26
wintun.c
26
wintun.c
@ -301,35 +301,31 @@ TunMapUbuffer(_Inout_ TUN_MAPPED_UBUFFER *MappedBuffer, _In_ VOID *UserAddress,
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return STATUS_SUCCESS;
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return STATUS_ALREADY_INITIALIZED;
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}
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try
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{
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ProbeForWrite(UserAddress, Size, 1);
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ProbeForRead(UserAddress, Size, 1);
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MappedBuffer->Mdl = IoAllocateMdl(UserAddress, Size, FALSE, FALSE, NULL);
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if (!MappedBuffer->Mdl)
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return STATUS_INSUFFICIENT_RESOURCES;
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MmProbeAndLockPages(MappedBuffer->Mdl, KernelMode, IoWriteAccess);
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try
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{
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MmProbeAndLockPages(MappedBuffer->Mdl, UserMode, IoWriteAccess);
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}
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except(EXCEPTION_EXECUTE_HANDLER)
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{
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IoFreeMdl(MappedBuffer->Mdl);
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MappedBuffer->Mdl = NULL;
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return STATUS_INVALID_USER_BUFFER;
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}
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MappedBuffer->KernelAddress =
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MmGetSystemAddressForMdlSafe(MappedBuffer->Mdl, NormalPagePriority | MdlMappingNoExecute);
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if (!MappedBuffer->KernelAddress)
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{
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MmUnlockPages(MappedBuffer->Mdl);
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IoFreeMdl(MappedBuffer->Mdl);
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MappedBuffer->Mdl = NULL;
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return STATUS_INSUFFICIENT_RESOURCES;
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}
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MappedBuffer->UserAddress = UserAddress;
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MappedBuffer->Size = Size;
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}
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except(EXCEPTION_EXECUTE_HANDLER)
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{
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if (MappedBuffer->Mdl)
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{
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IoFreeMdl(MappedBuffer->Mdl);
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MappedBuffer->Mdl = NULL;
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}
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return STATUS_INVALID_USER_BUFFER;
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}
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return STATUS_SUCCESS;
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}
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