On Wed, Sep 16, 2020 at 05:15:10PM +0200, Laszlo Ersek wrote: > The documentation on g_byte_array_free() > <https://developer.gnome.org/glib/stable/glib-Byte-Arrays.html#g-byte-array-free> > says: > > > Returns > > > > the element data if free_segment is FALSE, otherwise NULL. The element > > data should be freed using g_free(). > > Because we currently call g_byte_array_free() with free_segment=TRUE, we > end up passing data=NULL to fw_cfg_add_file(). > > On the plus side, fw_cfg_data_read() and fw_cfg_dma_transfer() both deal > with NULL data gracefully: QEMU does not crash when the guest reads such > an item, the guest just gets a properly sized, but zero-filled blob. > > However, the bug breaks UEFI HTTPS boot, as the IANA_TLS_CIPHER array, > generated otherwise correctly by the "tls-cipher-suites" object, is in > effect replaced with a zero blob. > > Fix the issue by passing free_segment=FALSE to g_byte_array_free(): > > - the caller (fw_cfg_add_from_generator()) temporarily assumes ownership > of the generated byte array, > > - then ownership of the byte array is transfered to fw_cfg, as > fw_cfg_add_file() links (not copies) "data" into fw_cfg. > > Cc: "Daniel P. Berrangé" <[email protected]> > Cc: "Philippe Mathieu-Daudé" <[email protected]> > Cc: Gerd Hoffmann <[email protected]> > Fixes: 3203148917d035b09f71986ac2eaa19a352d6d9d > Signed-off-by: Laszlo Ersek <[email protected]> > --- > hw/nvram/fw_cfg.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Daniel P. Berrangé <[email protected]> Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
