From: Neil Armstrong <neil.armstrong@linaro.org>
To: Douglas Anderson <dianders@chromium.org>,
dri-devel@lists.freedesktop.org
Cc: Linus Walleij <linus.walleij@linaro.org>,
Jani Nikula <jani.nikula@linux.intel.com>,
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
Cong Yang <yangcong5@huaqin.corp-partner.google.com>,
Hsin-Yi Wang <hsinyi@google.com>,
Brian Norris <briannorris@chromium.org>,
Sam Ravnborg <sam@ravnborg.org>,
Javier Martinez Canillas <javierm@redhat.com>,
Joel Selvaraj <jo@jsfamily.in>,
lvzhaoxiong@huaqin.corp-partner.google.com,
Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@gmail.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/9] drm/mipi-dsi: Fix theoretical int overflow in mipi_dsi_dcs_write_seq()
Date: Thu, 2 May 2024 09:26:40 +0200 [thread overview]
Message-ID: <ffce0bd4-6bd2-4197-9f89-b312ad7eabe7@linaro.org> (raw)
In-Reply-To: <20240501084109.v3.1.I30fa4c8348ea316c886ef8a522a52fed617f930d@changeid>
On 01/05/2024 17:41, Douglas Anderson wrote:
> The mipi_dsi_dcs_write_seq() macro makes a call to
> mipi_dsi_dcs_write_buffer() which returns a type ssize_t. The macro
> then stores it in an int and checks to see if it's negative. This
> could theoretically be a problem if "ssize_t" is larger than "int".
>
> To see the issue, imagine that "ssize_t" is 32-bits and "int" is
> 16-bits, you could see a problem if there was some code out there that
> looked like:
>
> mipi_dsi_dcs_write_seq(dsi, cmd, <32767 bytes as arguments>);
>
> ...since we'd get back that 32768 bytes were transferred and 32768
> stored in a 16-bit int would look negative.
>
> Though there are no callsites where we'd actually hit this (even if
> "int" was only 16-bit), it's cleaner to make the types match so let's
> fix it.
>
> Fixes: 2a9e9daf7523 ("drm/mipi-dsi: Introduce mipi_dsi_dcs_write_seq macro")
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
>
> Changes in v3:
> - Use %zd in print instead of casting errors to int.
>
> Changes in v2:
> - New
>
> include/drm/drm_mipi_dsi.h | 24 ++++++++++++------------
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
> index 82b1cc434ea3..70ce0b8cbc68 100644
> --- a/include/drm/drm_mipi_dsi.h
> +++ b/include/drm/drm_mipi_dsi.h
> @@ -333,18 +333,18 @@ int mipi_dsi_dcs_get_display_brightness_large(struct mipi_dsi_device *dsi,
> * @cmd: Command
> * @seq: buffer containing data to be transmitted
> */
> -#define mipi_dsi_dcs_write_seq(dsi, cmd, seq...) \
> - do { \
> - static const u8 d[] = { cmd, seq }; \
> - struct device *dev = &dsi->dev; \
> - int ret; \
> - ret = mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d)); \
> - if (ret < 0) { \
> - dev_err_ratelimited( \
> - dev, "sending command %#02x failed: %d\n", \
> - cmd, ret); \
> - return ret; \
> - } \
> +#define mipi_dsi_dcs_write_seq(dsi, cmd, seq...) \
> + do { \
> + static const u8 d[] = { cmd, seq }; \
> + struct device *dev = &dsi->dev; \
> + ssize_t ret; \
> + ret = mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d)); \
> + if (ret < 0) { \
> + dev_err_ratelimited( \
> + dev, "sending command %#02x failed: %zd\n", \
> + cmd, ret); \
> + return ret; \
> + } \
> } while (0)
>
> /**
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
next prev parent reply other threads:[~2024-05-02 7:26 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-01 15:41 [PATCH v3 0/9] drm/mipi-dsi: Reduce bloat and add funcs for cleaner init seqs Douglas Anderson
2024-05-01 15:41 ` [PATCH v3 1/9] drm/mipi-dsi: Fix theoretical int overflow in mipi_dsi_dcs_write_seq() Douglas Anderson
2024-05-02 7:26 ` Neil Armstrong [this message]
2024-05-02 8:15 ` Linus Walleij
2024-05-01 15:41 ` [PATCH v3 2/9] drm/mipi-dsi: Fix theoretical int overflow in mipi_dsi_generic_write_seq() Douglas Anderson
2024-05-02 7:26 ` Neil Armstrong
2024-05-02 8:15 ` Linus Walleij
2024-05-01 15:41 ` [PATCH v3 3/9] drm/mipi-dsi: mipi_dsi_*_write functions don't need to ratelimit prints Douglas Anderson
2024-05-02 7:27 ` Neil Armstrong
2024-05-02 8:16 ` Linus Walleij
2024-05-01 15:41 ` [PATCH v3 4/9] drm/mipi-dsi: Reduce driver bloat of mipi_dsi_*_write_seq() Douglas Anderson
2024-05-02 7:27 ` Neil Armstrong
2024-05-02 8:23 ` Linus Walleij
2024-05-02 16:59 ` Doug Anderson
2024-05-01 15:41 ` [PATCH v3 5/9] drm/mipi-dsi: Introduce mipi_dsi_*_write_seq_multi() Douglas Anderson
2024-05-02 7:28 ` Neil Armstrong
2024-05-06 6:22 ` Linus Walleij
2024-05-01 15:41 ` [PATCH v3 6/9] drm/panel: novatek-nt36672e: Switch to mipi_dsi_dcs_write_seq_multi() Douglas Anderson
2024-05-01 15:41 ` [PATCH v3 7/9] drm/panel: boe-tv101wum-nl6: Don't use a table for initting panels Douglas Anderson
2024-05-02 13:41 ` Linus Walleij
2024-05-02 16:40 ` Doug Anderson
2024-05-01 15:41 ` [PATCH v3 8/9] drm/panel: ili9882t: " Douglas Anderson
2024-05-06 6:19 ` Linus Walleij
2024-05-01 15:41 ` [PATCH v3 9/9] drm/panel: innolux-p079zca: " Douglas Anderson
2024-05-03 16:32 ` Doug Anderson
2024-05-06 6:45 ` Linus Walleij
2024-05-02 7:48 ` [PATCH v3 0/9] drm/mipi-dsi: Reduce bloat and add funcs for cleaner init seqs Neil Armstrong
2024-05-02 14:27 ` Doug Anderson
2024-05-02 16:05 ` neil.armstrong
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