Am 06.05.2015 um 19:50 hat Max Reitz geschrieben: > On 05.05.2015 11:28, Fam Zheng wrote: > >Richard Jones caught this bug with afl fuzzer. > > > >In fact, that's the only possible value to overflow (extent->l1_size = > >0x20000000) l1_size: > > > >l1_size = extent->l1_size * sizeof(long) => 0x80000000; > > > >g_try_malloc returns NULL because l1_size is interpreted as negative > >during type casting from 'int' to 'gsize', which yields a enormous > >value. Hence, by coincidence, we get a "not too bad" behavior: > > > >qemu-img: Could not open '/tmp/afl6.img': Could not open > >'/tmp/afl6.img': Cannot allocate memory > > > >Values larger than 0x20000000 will be refused by the validation in > >vmdk_add_extent. > > > >Values smaller than 0x20000000 will not overflow l1_size. > > > >Reported-by: Richard W.M. Jones <rjo...@redhat.com> > >Signed-off-by: Fam Zheng <f...@redhat.com> > >--- > > block/vmdk.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > Okay, so because size_t is unsigned, this will not overflow on > systems with sizeof(size_t) == 4 either. > > Reviewed-by: Max Reitz <mre...@redhat.com>
Thanks, applied to the block branch. I think this one is for stable, too. Kevin
