From:   Thomas Zimmermann <tzimmermann@suse.de>
To:     deller@gmx.de, paulus@samba.org, benh@kernel.crashing.org,
        linux@armlinux.org.uk, pjones@redhat.com, timur@kernel.org,
        adaplas@gmail.com, s.hauer@pengutronix.de, shawnguo@kernel.org,
        mbroemme@libmpq.org, thomas@winischhofer.net,
        James.Bottomley@HansenPartnership.com, spock@gentoo.org,
        sudipm.mukherjee@gmail.com, teddy.wang@siliconmotion.com,
        geert+renesas@glider.be, corbet@lwn.net
Cc:     linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org,
        Thomas Zimmermann <tzimmermann@suse.de>
Subject: [PATCH 87/99] fbdev/uvesafb: Duplicate video-mode option string
Date:   Mon,  6 Mar 2023 17:00:04 +0100
Message-Id: <20230306160016.4459-88-tzimmermann@suse.de>
In-Reply-To: <20230306160016.4459-1-tzimmermann@suse.de>
References: <20230306160016.4459-1-tzimmermann@suse.de>
MIME-Version: 1.0
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Assume that the driver does not own the option string or its substrings
and hence duplicate the option string for the video mode. The driver only
parses the option string once as part of module initialization, so use
a static buffer to store the duplicated mode option. Linux automatically
frees the memory upon releasing the module.

Done in preparation of switching the driver to struct option_iter and
constifying the option string.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/uvesafb.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/uvesafb.c b/drivers/video/fbdev/uvesafb.c
index f09f483c219b..201f6bba0763 100644
--- a/drivers/video/fbdev/uvesafb.c
+++ b/drivers/video/fbdev/uvesafb.c
@@ -1851,7 +1851,15 @@ static int uvesafb_setup(char *options)
 		else if (!strncmp(this_opt, "vbemode:", 8))
 			vbemode = simple_strtoul(this_opt + 8, NULL, 0);
 		else if (this_opt[0] >= '0' && this_opt[0] <= '9') {
-			mode_option = this_opt;
+			static char mode_option_buf[256];
+			int ret;
+
+			ret = snprintf(mode_option_buf, sizeof(mode_option_buf), "%s", this_opt);
+			if (WARN(ret < 0, "uvesafb: ignoring invalid option, ret=%d\n", ret))
+				continue;
+			if (WARN(ret >= sizeof(mode_option_buf), "uvesafb: option too long\n"))
+				continue;
+			mode_option = mode_option_buf;
 		} else {
 			pr_warn("unrecognized option %s\n", this_opt);
 		}
-- 
2.39.2