Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 24 Jul 2019 10:08:57 -0700 | Subject | Re: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms |
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On Wed, Jul 24, 2019 at 6:09 AM Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote: > > The kernel's snprintf() does not behave in a non-standard way, at least > not with respect to its return value.
Note that the kernels snprintf() *does* very much protect against the overflow case - not by changing the return value, but simply by having
/* Reject out-of-range values early. Large positive sizes are used for unknown buffer sizes. */ if (WARN_ON_ONCE(size > INT_MAX)) return 0;
at the very top.
So you can't actually overflow in the kernel by using the repeated
offset += vsnprintf( .. size - offset ..);
model.
Yes, it's the wrong thing to do, but it is still _safe_.
Linus
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