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From: "Alexey V. Vissarionov" <gremlin@altlinux.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: "Alexey V. Vissarionov" <gremlin@altlinux.org>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Thomas Abraham <thomas.abraham@linaro.org>,
	Kukjin Kim <kgene.kim@samsung.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, linux-serial@vger.kernel.org,
	lvc-project@linuxtesting.org
Subject: Re: [PATCH] serial: samsung: fix buffer size for clk_name
Date: Mon, 16 Jan 2023 21:26:11 +0300	[thread overview]
Message-ID: <20230116182611.GA30526@altlinux.org> (raw)
In-Reply-To: <b82b1194-622c-fc65-d831-7731c72264b7@linaro.org>

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On 2023-01-16 17:16:59 +0100, Krzysztof Kozlowski wrote:

 >> Although very unlikely, the 'clk_num' value may be as big
 >> as 2**32 - 1 (uint32_max),
 > How it could be that high? Code has num_clks defined from 1
 > to 4 and it is used as strict boundary for the loop so how
 > it could end up here with higher value?

That's why I called this "very unlikely". However, nobody can
definitely exclude the possibility of extending this limit in
the future.

 > s3c24xx_serial_getsource() also returns value & with mask,
 > so up to 4 max.

Possibly, clk_num should be uint8_t then - so the buffer size
could be extended up to only 17 bytes ("clk_uart_baud255\0")
with format specifiers changed to "%u", or 18 bytes for "%d"
(clk_uart_baud-128\0).

 > This does not look like real issue but some change to satisfy
 > static code analyzers, so I don't think it's correct approach.

Although I agree this is probably only a theoretical issue, it's
always easier to spend several bytes than to prove that we don't
need to.

But, anyway, the final decision is up to you.


-- 
Alexey V. Vissarionov
gremlin ПРИ altlinux ТЧК org; +vii-cmiii-ccxxix-lxxix-xlii
GPG: 0D92F19E1C0DC36E27F61A29CD17E2B43D879005 @ hkp://keys.gnupg.net

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WARNING: multiple messages have this Message-ID (diff)
From: "Alexey V. Vissarionov" <gremlin@altlinux.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: "Alexey V. Vissarionov" <gremlin@altlinux.org>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Thomas Abraham <thomas.abraham@linaro.org>,
	Kukjin Kim <kgene.kim@samsung.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, linux-serial@vger.kernel.org,
	lvc-project@linuxtesting.org
Subject: Re: [PATCH] serial: samsung: fix buffer size for clk_name
Date: Mon, 16 Jan 2023 21:26:11 +0300	[thread overview]
Message-ID: <20230116182611.GA30526@altlinux.org> (raw)
In-Reply-To: <b82b1194-622c-fc65-d831-7731c72264b7@linaro.org>


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On 2023-01-16 17:16:59 +0100, Krzysztof Kozlowski wrote:

 >> Although very unlikely, the 'clk_num' value may be as big
 >> as 2**32 - 1 (uint32_max),
 > How it could be that high? Code has num_clks defined from 1
 > to 4 and it is used as strict boundary for the loop so how
 > it could end up here with higher value?

That's why I called this "very unlikely". However, nobody can
definitely exclude the possibility of extending this limit in
the future.

 > s3c24xx_serial_getsource() also returns value & with mask,
 > so up to 4 max.

Possibly, clk_num should be uint8_t then - so the buffer size
could be extended up to only 17 bytes ("clk_uart_baud255\0")
with format specifiers changed to "%u", or 18 bytes for "%d"
(clk_uart_baud-128\0).

 > This does not look like real issue but some change to satisfy
 > static code analyzers, so I don't think it's correct approach.

Although I agree this is probably only a theoretical issue, it's
always easier to spend several bytes than to prove that we don't
need to.

But, anyway, the final decision is up to you.


-- 
Alexey V. Vissarionov
gremlin ПРИ altlinux ТЧК org; +vii-cmiii-ccxxix-lxxix-xlii
GPG: 0D92F19E1C0DC36E27F61A29CD17E2B43D879005 @ hkp://keys.gnupg.net

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  reply	other threads:[~2023-01-16 18:37 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-16 14:16 [PATCH] serial: samsung: fix buffer size for clk_name Alexey V. Vissarionov
2023-01-16 14:16 ` Alexey V. Vissarionov
2023-01-16 16:16 ` Krzysztof Kozlowski
2023-01-16 16:16   ` Krzysztof Kozlowski
2023-01-16 18:26   ` Alexey V. Vissarionov [this message]
2023-01-16 18:26     ` Alexey V. Vissarionov
2023-01-19 14:52 ` Greg Kroah-Hartman
2023-01-19 14:52   ` Greg Kroah-Hartman
2023-02-01  2:44   ` [PATCH v2] " Alexey V. Vissarionov
2023-02-01  2:44     ` Alexey V. Vissarionov
2023-02-01  7:09     ` Krzysztof Kozlowski
2023-02-01  7:09       ` Krzysztof Kozlowski
2023-02-01 13:06     ` Greg Kroah-Hartman
2023-02-01 13:06       ` Greg Kroah-Hartman

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