Re: [PATCH 1/8] log: Avoid buffer overrun in DbgPrint interception

[Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>]

On 14/08/2026 09:30, Owen Smith wrote:
> Truncate incomming strings to fit inside a Slot's Buffer
> 
> Assisted-by: ClaudeCode:claude-opus-4.8
> Signed-off-by: Owen Smith <owen.smith@xxxxxxxxxx>

Reviewed-by: Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>

> ---
>   src/xen/log.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/src/xen/log.c b/src/xen/log.c
> index 8673105..93039f6 100644
> --- a/src/xen/log.c
> +++ b/src/xen/log.c
> @@ -545,6 +545,7 @@ LogDebugPrint(
>   {
>       PLOG_CONTEXT        Context = &LogContext;
>       KIRQL               Irql;
> +    ULONG               Length;
>       PLOG_SLOT           Slot;
>   
>       UNREFERENCED_PARAMETER(ComponentId);
> @@ -571,9 +572,14 @@ LogDebugPrint(
>   
>       Slot = &Context->Slot[Context->Pending++];
>   
> +    // truncate long log lines - avoid buffer overrun on Slot->Buffer
> +    Length = Ansi->Length >= LOG_BUFFER_SIZE ?
> +                            LOG_BUFFER_SIZE - 1:
> +                            Ansi->Length;
> +
>       Slot->Level = 1 << Level;
> -    RtlCopyMemory(Slot->Buffer, Ansi->Buffer, Ansi->Length);
> -    Slot->Offset = Ansi->Length;
> +    RtlCopyMemory(Slot->Buffer, Ansi->Buffer, Length);
> +    Slot->Offset = Length;
>   
>       ReleaseHighLock(&Context->Lock, Irql);
>   



--
Ngoc Tu Dinh | Vates XCP-ng Developer

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