media: vidtv: initialize local pointers upon transfer of memory ownership

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: media: vidtv: initialize local pointers upon transfer of memory ownership vidtv_channel_si_init() creates a temporary list (program, service, event) and ownership of the memory itself is transferred to the PAT/SDT/EIT tables through vidtv_psi_pat_program_assign(), vidtv_psi_sdt_service_assign(), vidtv_psi_eit_event_assign(). The problem here is that the local pointer where the memory ownership transfer was completed is not initialized to NULL. This causes the vidtv_psi_pmt_create_sec_for_each_pat_entry() function to fail, and in the flow that jumps to free_eit, the memory that was freed by vidtv_psi_*_table_destroy() can be accessed again by vidtv_psi_*_event_destroy() due to the uninitialized local pointer, so it is freed once again. Therefore, to prevent use-after-free and double-free vulnerability, local pointers must be initialized to NULL when transferring memory ownership.

References

• https://git.kernel.org/stable/c/c342e294dac4988c8ada759b2f057246e48c5108
• https://git.kernel.org/stable/c/12ab6ebb37789b84073e83e4d9b14a5e0d133323
• https://git.kernel.org/stable/c/3caa18d35f1dabe85a3dd31bc387f391ac9f9b4e
• https://git.kernel.org/stable/c/fb9bd6d8d314b748e946ed6555eb4a956ee8c4d8
• https://git.kernel.org/stable/c/a69c7fd603bf5ad93177394fbd9711922ee81032
• https://git.kernel.org/stable/c/30f4d4e5224a9e44e9ceb3956489462319d804ce
• https://git.kernel.org/stable/c/98aabfe2d79f74613abc2b0b1cef08f97eaf5322