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Correct and simplify page locking

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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2019-06-26 19:25:03 +00:00
parent 3d84bddcc0
commit 88bde5b28e
1 changed files with 18 additions and 22 deletions
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wintun.c
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@ -301,35 +301,31 @@ TunMapUbuffer(_Inout_ TUN_MAPPED_UBUFFER *MappedBuffer, _In_ VOID *UserAddress,
return STATUS_SUCCESS; return STATUS_SUCCESS;
return STATUS_ALREADY_INITIALIZED; return STATUS_ALREADY_INITIALIZED;
} }
MappedBuffer->Mdl = IoAllocateMdl(UserAddress, Size, FALSE, FALSE, NULL);
if (!MappedBuffer->Mdl)
return STATUS_INSUFFICIENT_RESOURCES;
try try
{ {
ProbeForWrite(UserAddress, Size, 1); MmProbeAndLockPages(MappedBuffer->Mdl, UserMode, IoWriteAccess);
ProbeForRead(UserAddress, Size, 1);
MappedBuffer->Mdl = IoAllocateMdl(UserAddress, Size, FALSE, FALSE, NULL);
if (!MappedBuffer->Mdl)
return STATUS_INSUFFICIENT_RESOURCES;
MmProbeAndLockPages(MappedBuffer->Mdl, KernelMode, IoWriteAccess);
MappedBuffer->KernelAddress =
MmGetSystemAddressForMdlSafe(MappedBuffer->Mdl, NormalPagePriority | MdlMappingNoExecute);
if (!MappedBuffer->KernelAddress)
{
IoFreeMdl(MappedBuffer->Mdl);
MappedBuffer->Mdl = NULL;
return STATUS_INSUFFICIENT_RESOURCES;
}
MappedBuffer->UserAddress = UserAddress;
MappedBuffer->Size = Size;
} }
except(EXCEPTION_EXECUTE_HANDLER) except(EXCEPTION_EXECUTE_HANDLER)
{ {
if (MappedBuffer->Mdl) IoFreeMdl(MappedBuffer->Mdl);
{ MappedBuffer->Mdl = NULL;
IoFreeMdl(MappedBuffer->Mdl);
MappedBuffer->Mdl = NULL;
}
return STATUS_INVALID_USER_BUFFER; return STATUS_INVALID_USER_BUFFER;
} }
MappedBuffer->KernelAddress =
MmGetSystemAddressForMdlSafe(MappedBuffer->Mdl, NormalPagePriority | MdlMappingNoExecute);
if (!MappedBuffer->KernelAddress)
{
MmUnlockPages(MappedBuffer->Mdl);
IoFreeMdl(MappedBuffer->Mdl);
MappedBuffer->Mdl = NULL;
return STATUS_INSUFFICIENT_RESOURCES;
}
MappedBuffer->UserAddress = UserAddress;
MappedBuffer->Size = Size;
return STATUS_SUCCESS; return STATUS_SUCCESS;
} }