On Wed, May 16, 2012 at 03:33:45PM -0700, Anton Vorontsov wrote:
> On Wed, May 16, 2012 at 09:49:11AM -0700, Kees Cook wrote:
> [...]
> > > +#ifdef CONFIG_PSTORE_CONSOLE
> > > +static void pstore_console_write(struct console *con, const char *s, unsigned c)
> > > +{
> > > + strncpy(psinfo->buf, s, c);
> >
> > The size of psinfo->buf needs to be the length argument to strncpy,
> > not the size of "s". If "s" isn't NULL terminated, then the min of c
> > and buf's size should be used. And if this should be NULL terminated
> > in buf, that needs to be added manually since strncpy won't do it if
> > it hits the max length argument.
>
> Whoops. Will fix it, thanks!
Actually, we shouldn't bother with NUL-termination at all. We should
do, is just carefully copy all 'c' elements of 's' into pstore in
'pstore->bufsize' chunks.
So, the code should be something along these lines:
static void pstore_console_write(struct console *con, const char *s, unsigned c)
{
const char *e = s + c;
while (s < e) {
if (c > psinfo->bufsize)
c = psinfo->bufsize;
memcpy(psinfo->buf, s, c);
psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
s += c;
c = e - s;
}
}
Here, in case of c > bufsize, we can't just copy bufsize bytes once and
exit, since 'bufsize' doesn't tell anything about TYPE_CONSOLE's internal
storage size (today console's persistent ram zone size and pstore's
bufsize are equal, but this is something we may change soon, i.e. make
TYPE_DMESG and TYPE_CONSOLE record sizes configurable).
Thanks,
--
Anton Vorontsov
Email: cbouatmailru@xxxxxxxxx
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