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From: Anshuman <anshumantewari123@gmail.com>
To: kees@kernel.org
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Subject: Re: [PATCH 01/11] params: bound array element output to the caller's page buffer
Date: Sun,  4 Oct 2026 16:17:41 +0530	[thread overview]
Message-ID: <20261004104741.51238-1-anshumantewari123@gmail.com> (raw)
In-Reply-To: <20260521133326.2465264-1-kees@kernel.org>

On Thu, May 21, 2026 at 06:33:14AM -0700, Kees Cook wrote:
> ret = min(ret, (int)(PAGE_SIZE - 1 - off));
> if (!ret)
> 	break;

One question about the truncation behavior here: when an element does
not fully fit in the remaining buffer, this min() can cause only part
of that element to be copied. For example, if the remaining space is
4 bytes and the next element produces "123456789\n", the resulting
output could contain only "1234".

This leaves the reader with no way to distinguish a genuinely short
value from one that was truncated due to the PAGE_SIZE limit, while
the array otherwise still looks like a normal comma-separated list.

Is this partial-element truncation intentional for this patch, or is
the expectation that it gets handled as part of the later seq_buf
conversion? Would it be preferable to avoid copying an element unless
it fits completely, and leave the larger-buffer case to be addressed
later in the series?

  parent reply	other threads:[~2026-10-04 10:51 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-21 13:33 [PATCH 00/11] Convert moduleparams to seq_buf Kees Cook
2026-05-21 13:33 ` [PATCH 01/11] params: bound array element output to the caller's page buffer Kees Cook
2026-05-21 16:46   ` David Laight
2026-06-01 20:23     ` Matthew Wilcox
2026-06-02 11:26   ` Andy Shevchenko
2026-06-02 12:33     ` Jason Gunthorpe
2026-06-02 13:04     ` David Laight
2026-10-04 10:47   ` Anshuman [this message]
2026-05-21 13:33 ` [PATCH 02/11] panic: Replace panic_print_get() with generic helper Kees Cook
2026-05-21 13:33 ` [PATCH 03/11] moduleparam: Add DEFINE_KERNEL_PARAM_OPS macro family Kees Cook
2026-05-25 13:27   ` Petr Pavlu
2026-05-21 13:33 ` [PATCH 04/11] treewide: Convert struct kernel_param_ops initializers to DEFINE_KERNEL_PARAM_OPS Kees Cook
2026-05-21 13:59   ` Sean Christopherson
2026-05-22 17:01   ` Rafael J. Wysocki
2026-05-23  0:38   ` SeongJae Park
2026-05-25 13:35   ` Petr Pavlu
2026-06-10 21:06     ` jim.cromie
2026-05-21 13:33 ` [PATCH 05/11] moduleparam: Rename .get field to .get_str Kees Cook
2026-05-21 13:33 ` [PATCH 06/11] moduleparam: Add seq_buf-based .get callback alongside .get_str Kees Cook
2026-05-25 16:19   ` Petr Pavlu
2026-05-21 13:33 ` [PATCH 07/11] moduleparam: Route DEFINE_KERNEL_PARAM_OPS get pointer via _Generic Kees Cook
2026-05-25 16:24   ` Petr Pavlu
2026-05-21 13:33 ` [PATCH 08/11] params: Convert generic kernel_param_ops .get helpers to seq_buf Kees Cook
2026-05-25 17:10   ` Petr Pavlu
2026-05-21 13:33 ` [PATCH 09/11] treewide: Convert custom kernel_param_ops .get callbacks to seq_buf via cocci Kees Cook
2026-05-21 13:45   ` Sean Christopherson
2026-05-22 17:03   ` Rafael J. Wysocki
2026-05-23  0:45   ` SeongJae Park
2026-05-21 13:33 ` [PATCH 10/11] treewide: Manually convert custom kernel_param_ops .get callbacks Kees Cook
2026-05-21 17:44   ` Jani Nikula
2026-05-22 17:05   ` Rafael J. Wysocki
2026-05-21 13:33 ` [PATCH 11/11] moduleparam: Drop legacy kernel_param_ops .get_str field and dispatch logic Kees Cook
2026-05-26  6:53 ` [PATCH 00/11] Convert moduleparams to seq_buf Petr Pavlu
2026-06-01 19:59   ` Kees Cook

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