On 12/15/24 16:15, Thomas Weißschuh wrote:

It should not be possible for every user to override the EDID. Limit it to the system administrator.

Fixes: 8ef8cc4fca4a ("staging: udlfb: support for writing backup EDID to sysfs file") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh linux@weissschuh.net

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The EDID passed through sysfs is only used as a fallback if the hardware does not provide one. To me it still feels incorrect to have this world-writable.

I'm wondering if there is any real danger to the system integrity if a user writes an own EDID (or a broken one)? I mean, the only reason to use an own EDID is if you are a desktop user, and then you usually are not a root user. So, user-writeable *seems* safe to me, especially since the provided EDID is only used if a real one isn't provided by the monitor.

Maybe Bernie has an opinion here?

Helge

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drivers/video/fbdev/udlfb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c index 71ac9e36f67c68aa7a54dce32323047a2a9a48bf..391bdb71197549caa839d862f0ce7456dc7bf9ec 100644 --- a/drivers/video/fbdev/udlfb.c +++ b/drivers/video/fbdev/udlfb.c @@ -1480,7 +1480,7 @@ static ssize_t metrics_reset_store(struct device *fbdev,

static const struct bin_attribute edid_attr = { .attr.name = "edid",

• .attr.mode = 0666,

• .attr.mode = 0644, .size = EDID_LENGTH, .read = edid_show, .write = edid_store

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base-commit: 2d8308bf5b67dff50262d8a9260a50113b3628c6 change-id: 20241215-udlfb-perms-bb6ed270facf

Best regards,