From: Dave Hansen <dave.hansen@intel.com>
To: Peter Fang <peter.fang@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Kiryl Shutsemau <kas@kernel.org>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev,
kvm@vger.kernel.org, Xiaoyao Li <xiaoyao.li@intel.com>,
Binbin Wu <binbin.wu@linux.intel.com>,
Tony Lindgren <tony.lindgren@linux.intel.com>,
Sean Christopherson <seanjc@google.com>,
Artem Bityutskiy <artem.bityutskiy@intel.com>
Subject: Re: [PATCH v5 3/6] virt: tdx-guest: Calculate the Quote buffer size safely
Date: Mon, 28 Sep 2026 08:50:10 -0700 [thread overview]
Message-ID: <1753d73f-7464-4476-9fb7-c0a12157a6ab@intel.com> (raw)
In-Reply-To: <20260928100913.2265687-4-peter.fang@intel.com>
On 9/28/26 03:08, Peter Fang wrote:
> -#define TDX_QUOTE_MAX_LEN (GET_QUOTE_BUF_SIZE - sizeof(struct tdx_quote_buf))
> +#define TDX_QUOTE_TOTAL_SIZE(n) struct_size_t(struct tdx_quote_buf, data, n)
>
> /* struct tdx_quote_buf: Format of Quote request buffer.
> * @version: Quote format version, filled by TD.
> @@ -314,7 +314,7 @@ static int tdx_report_new_locked(struct tsm_report *report, void *data)
>
> out_len = READ_ONCE(quote_buf->out_len);
>
> - if (out_len > TDX_QUOTE_MAX_LEN)
> + if (TDX_QUOTE_TOTAL_SIZE(out_len) > GET_QUOTE_BUF_SIZE)
> return -EFBIG;
Gah, this is awful. There are two different literal "data" things:
1. The function argument: void *data
2. The flexible array member: tdx_quote_buf->data[]
Worse, I think the function argument isn't even used, despite being
passed through at least one level of static, file-local TDX calls.
It becomes a *total* liability since there are so many "data" names
being tossed around.
I just committed this:
> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=x86/tdx&id=d48b2d347105436365280a3697a265aa4d37e96c
Any reason not to keep it?
next prev parent reply other threads:[~2026-09-28 15:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-28 10:08 [PATCH v5 0/6] tdx-guest: Make Quote buffer size dynamic Peter Fang
2026-09-28 10:08 ` [PATCH v5 1/6] x86/tdx: Take the Quote buffer as a generic pointer Peter Fang
2026-09-28 10:08 ` [PATCH v5 2/6] virt: tdx-guest: Give the Quote buffer an explicit type Peter Fang
2026-09-28 10:08 ` [PATCH v5 3/6] virt: tdx-guest: Calculate the Quote buffer size safely Peter Fang
2026-09-28 15:50 ` Dave Hansen [this message]
2026-09-28 10:08 ` [PATCH v5 4/6] virt: tdx-guest: Add a helper for the Quote buffer size Peter Fang
2026-09-28 16:13 ` Dave Hansen
2026-09-28 10:08 ` [PATCH v5 5/6] x86/tdx: Add a helper to query maximum Quote size Peter Fang
2026-09-28 10:08 ` [PATCH v5 6/6] virt: tdx-guest: Make the Quote buffer size dynamic Peter Fang
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