vmdk: Fix overflow if l1_size is 0x20000000
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. Cc: qemu-stable@nongnu.org Reported-by:Richard W.M. Jones <rjones@redhat.com> Signed-off-by:
Fam Zheng <famz@redhat.com> Reviewed-by:
Max Reitz <mreitz@redhat.com> Tested-by:
Richard W.M. Jones <rjones@redhat.com> Signed-off-by:
Kevin Wolf <kwolf@redhat.com> (cherry picked from commit 13c4941c) Signed-off-by:
Michael Roth <mdroth@linux.vnet.ibm.com>
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