media: dvb-net: fix OOB access in ULE extension header tables

In the Linux kernel, the following vulnerability has been resolved:

media: dvb-net: fix OOB access in ULE extension header tables

The ule_mandatory_ext_handlers[] and ule_optional_ext_handlers[] tables

in handle_one_ule_extension() are declared with 255 elements (valid

indices 0-254), but the index htype is derived from network-controlled

data as (ule_sndu_type & 0x00FF), giving a range of 0-255. When

htype equals 255, an out-of-bounds read occurs on the function pointer

table, and the OOB value may be called as a function pointer.

Add a bounds check on htype against the array size before either table

is accessed. Out-of-range values now cause the SNDU to be discarded.