2012/7/9, OGAWA Hirofumi <hirof...@mail.parknet.co.jp>: > Namjae Jeon <linkinj...@gmail.com> writes: > >>>> + /* >>>> + * calculate i_blocks and mmu_private from the actual number of >>>> + * allocated clusters instead of doing it from file size.This ensures >>>> + * that the preallocated disk space using FALLOC_FL_KEEP_SIZE is >>>> + * persistent across remounts and writes go into the allocated >>>> clusters. >>>> + */ >>>> + fat_calc_dir_size(inode); >>> >>> Looks like the wrong. If you didn't initialize preallocated space, the >>> data never be exposed to userland. It is security bug. >> As explained above, if we do append write instead of seeking into a >> random offset, there is no security risk. > > So it means? - if we didn't, there is. Yes, right. > >> The main disadvantage with initializing the preallocated space (as is >> done in case of without FALLOC_FL_KEEP_SIZE ) is it takes long time >> for bigger allocation sizes. It took ~70 seconds to preallocate 2GB on >> our target if FALLOC_FL_KEEP_SIZE is not set. > > It doesn't become the reason to expose uninitialized data. I agree.. If I try to change code for initializing the preallocated space, Is this patch acceptable ?
Thanks Ogawa. > > Thanks. > -- > OGAWA Hirofumi <hirof...@mail.parknet.co.jp> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
