Messages in this thread | | | Date | Thu, 31 May 2018 09:24:28 +0100 | From | Daniel Thompson <> | Subject | Re: [PATCH] kdb: prefer strlcpy to strncpy |
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On Wed, May 30, 2018 at 10:47:13PM +0200, Geert Uytterhoeven wrote: > H Daniel, > > On Wed, May 30, 2018 at 4:34 PM, Daniel Thompson > <daniel.thompson@linaro.org> wrote: > > On Tue, May 29, 2018 at 07:01:35PM -0700, Nick Desaulniers wrote: > >> On Tue, May 29, 2018 at 12:57 AM, Arnd Bergmann <arnd@arndb.de> wrote: > >> > On Tue, May 29, 2018 at 7:57 AM, Nick Desaulniers > >> > <nick.desaulniers@gmail.com> wrote: > >> >> Fixes stringop-truncation and stringop-overflow warnings from gcc-8. > > >> Eric points out that this will leak kernel memory if size is less than > >> sizeof src. > > > > Don't quite understand what this means (there's no allocation here, how > > can there be a leak?) but the symbol completion certainly won't work if > > we truncate the copy here. > > Not leak an is memory leak, but leak as in information leak of uninitialized > data to userspace (if the buffer is ever copied to userspace).
I see... I saw "leak", I saw "memory" and was perhaps too quick to link the two together.
The underlying bug is a buffer overflow (so a good catch and I look forward to a v2) but, with or without Nick's change, I can't see a leak in either sense of the word in the code that Arnd was commenting on[1].
Daniel.
[1] Clearly the undefined behaviour post-overflow *could* be a leak but I stopped analyzing after the overflow.
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