[PATCH 1/3] fix code generation for emit_size_read() to check for buffer overflow

Thomas Haller thaller at redhat.com
Wed Oct 8 01:42:52 PDT 2014


On Wed, 2014-10-08 at 10:33 +0200, Aleksander Morgado wrote:
> On Wed, Oct 8, 2014 at 10:00 AM, Thomas Haller <thaller at redhat.com> wrote:
> >
> >> The code doesn't return a GError in validate(), just does a g_warning,
> >> because we don't want to halt the full message parsing if we detect a
> >> TLV with wrong contents. An incorrect TLV, or just a TLV which we
> >> don't know how to parse, shouldn't make the parsing of other TLVs
> >> break. validate() in this case is done for each TLV while we parse the
> >> received message; and we do an initial parsing of the whole message by
> >> default.
> >>
> >> Another, maybe better, approach would be to only parse those TLVs that
> >> the user wants. i.e. the 'output' bundle would only fill in the parsed
> >> fields when a given TLV is requested. And in that case, if a single
> >> TLV is requested from the output bundle, we could then run validate()
> >> and return a GError. IIRC this is more or less what I did in libmbim
> >> actually, where the result of a client operation is not an already
> >> parsed output bundle, but the actual message itself, and in that case
> >> only the user-requested TLVs get parsed and built.
> >
> > The validation code uses g_warning() in case of failure. I think that is
> > not a great way to report runtime errors/warnings. I think it's suitable
> > to warn about bugs.
> >
> > One reason is that I find it useful to run applications with
> > G_DEBUG=fatal-warnings. Which does not work if the application (or even
> > one of it's libraries) uses g_warning for non-bugs.
> >
> > I think a library should not print anything (or possibly only when
> > having a QMI_DEBUG variable defined).
> 
> All libqmi logging is already done under the "Qmi" G_LOG_DOMAIN; so
> programs using libqmi should only get logs printed if a log handler
> was explicitly set for that log domain.

That's a good reason. Thanks for clarifying.

Thomas
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