P J P <ppan...@redhat.com> 于2020年9月22日周二 下午5:29写道: > > From: Prasad J Pandit <p...@fedoraproject.org> > > While transferring data via fdctrl_read/write_data() routines, > check that current drive does not have a null block pointer. > Avoid null pointer dereference. > > -> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Ffdc_nullptr1 > ==1658854==Hint: address points to the zero page. > #0 blk_inc_in_flight block/block-backend.c:1327 > #1 blk_prw block/block-backend.c:1299 > #2 blk_pwrite block/block-backend.c:1464 > #3 fdctrl_write_data hw/block/fdc.c:2418 > #4 fdctrl_write hw/block/fdc.c:962 > #5 portio_write ioport.c:205 > #6 memory_region_write_accessor memory.c:483 > #7 access_with_adjusted_size memory.c:544 > #8 memory_region_dispatch_write memory.c:1476 > > Reported-by: Ruhr-University <bugs-sys...@rub.de> > Signed-off-by: Prasad J Pandit <p...@fedoraproject.org>
Reviewed-by: Li Qiang <liq...@gmail.com> > --- > hw/block/fdc.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > Update v2: treat NULL blk pointer as an error > -> https://lists.nongnu.org/archive/html/qemu-devel/2020-09/msg06642.html > > diff --git a/hw/block/fdc.c b/hw/block/fdc.c > index 224bac504f..bf968dc66f 100644 > --- a/hw/block/fdc.c > +++ b/hw/block/fdc.c > @@ -1923,7 +1923,8 @@ static uint32_t fdctrl_read_data(FDCtrl *fdctrl) > fd_sector(cur_drv)); > return 0; > } > - if (blk_pread(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo, > + if (!cur_drv->blk > + || blk_pread(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo, > BDRV_SECTOR_SIZE) > < 0) { > FLOPPY_DPRINTF("error getting sector %d\n", > @@ -2427,7 +2428,8 @@ static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t > value) > if (pos == FD_SECTOR_LEN - 1 || > fdctrl->data_pos == fdctrl->data_len) { > cur_drv = get_cur_drv(fdctrl); > - if (blk_pwrite(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo, > + if (!cur_drv->blk > + || blk_pwrite(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo, > BDRV_SECTOR_SIZE, 0) < 0) { > FLOPPY_DPRINTF("error writing sector %d\n", > fd_sector(cur_drv)); > -- > 2.26.2 >