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Date: Sun, 5 Apr 2026 10:00:50 +0200
From: Greg KH <gregkh@linuxfoundation.org>
To: Delene Tchio Romuald <delenetchior1@gmail.com>
Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Subject: Re: [PATCH] staging: greybus: fix size_t underflow in
 cap_get_ims_certificate()
Message-ID: <2026040508-portable-natural-47ee@gregkh>
References: <20260404232242.68423-1-delenetchior1@gmail.com>
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In-Reply-To: <20260404232242.68423-1-delenetchior1@gmail.com>

On Sun, Apr 05, 2026 at 12:22:42AM +0100, Delene Tchio Romuald wrote:
> In cap_get_ims_certificate(), the certificate size is computed as:
> 
>   *size = op->response->payload_size - sizeof(*response);
> 
> Both operands are size_t (unsigned), so if a malformed Greybus module
> sends a response with payload_size smaller than sizeof(*response),
> the subtraction wraps to a very large value. The subsequent memcpy()
> then causes a heap buffer overflow.

How can you have a "malformed greybus module"?

Please fix your ai tool's threat model to be realistic :)

thanks,

greg k-h