Re: [RFC PATCH] qemu-keymap: properly check return from xkb_keymap_mod_get_index

[Peter Maydell]

On Tue, 20 Jun 2023 at 16:38, Alex Bennée <alex.bennee@linaro.org> wrote:
>
>
> Peter Maydell <peter.maydell@linaro.org> writes:
>
> > On Tue, 20 Jun 2023 at 16:04, Alex Bennée <alex.bennee@linaro.org> wrote:
> >>
> >> We can return XKB_MOD_INVALID which rightly gets flagged by sanitisers
> >> as an overly wide shift attempt.
> >>
> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> >> ---
> >>  qemu-keymap.c | 24 ++++++++++++++++--------
> >>  1 file changed, 16 insertions(+), 8 deletions(-)
> >
> > Looking at the code that works with the mask values
> > we are getting here, I think this ought to work
> > (if there's no AltGr modifier then the 0 mask means
> > the key state will be the same in normal and with the
> > altgr mask supplied, which we already check for).
> > Did you eyeball the output, though?
> >
> > Also, which keymap runs into this? Is it every keymap
> > for some new version of the xkb data (which would imply
> > that the problem is that the AltGr modifier has changed
> > name), or is it only one specific keymap that happens
> > to have no AltGr key?
>
> ar maybe? it only got flagged in clang-system once fedora was updated (I
> assume with better sanitizers):
>
>   [2773/3696] Generating pc-bios/keymaps/ar with a custom command
>   FAILED: pc-bios/keymaps/ar
>   /builds/stsquad/qemu/build/qemu-keymap -f pc-bios/keymaps/ar -l ar
>   ../qemu-keymap.c:223:16: runtime error: shift exponent 4294967295 is too 
> large for 32-bit type 'int'
>   SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior 
> ../qemu-keymap.c:223:16 in
>   [2774/3696] Generating pc-bios/edk2-x86_64-code.fd with a custom command 
> (wrapped by meson to capture output)
>   [2775/3696] Generating pc-bios/edk2-x86_64-secure-code.fd with a custom 
> command (wrapped by meson to capture output)
>   ninja: build stopped: subcommand failed.
>   make: *** [Makefile:153: run-ninja] Error 1

OK; how does the output look from the new qemu-keymap on
that system ?

thanks
-- PMM