From: Borislav Petkov

Sent: 24 August 2021 19:26

..

so looking at the code, we're merrily decrementing len but nothing's
checking whether len can become 0. Because if it does, strscpy() will
do:

	if (count == 0 || WARN_ON_ONCE(count > INT_MAX))
		return -E2BIG;

That -E2BIG is going to break something.
It means that you always have to do an error check whenever
you use the return value of strscpy().

Anything that does:
	offset += strscpy(...)
is broken.

It really wasn't a good idea for reporting 'truncated'.

	David

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