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Message-ID: <ZGuSeZcLfXNyCqtv@shell.armlinux.org.uk>
Date: Mon, 22 May 2023 17:04:09 +0100
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Azeem Shaikh <azeemshaikh38@...il.com>
Cc: linux-hardening@...r.kernel.org, linux-kernel@...r.kernel.org,
David Airlie <airlied@...il.com>,
Daniel Vetter <daniel@...ll.ch>,
dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] drm/i2c: tda998x: Replace all non-returning strlcpy with
strscpy
On Mon, May 22, 2023 at 03:53:50PM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with strscpy().
> No return values were used, so direct replacement is safe.
...
> memset(&cec_info, 0, sizeof(cec_info));
> - strlcpy(cec_info.type, "tda9950", sizeof(cec_info.type));
> + strscpy(cec_info.type, "tda9950", sizeof(cec_info.type));
Please explain how:
1) a C string can not be NUL terminated.
2) this source string could be longer than I2C_NAME_SIZE (20 bytes)
which is unlikely to ever shrink.
I'm not saying I disagree with the patch, but the boilerplate commit
message isn't correct for this change, and is actually misleading
for what the patch actually is.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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