platform/chrome: cros_ec_typec: zero out stale pointers

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: platform/chrome: cros_ec_typec: zero out stale pointers `cros_typec_get_switch_handles` allocates four pointers when obtaining type-c switch handles. These pointers are all freed if failing to obtain any of them; therefore, pointers in `port` become stale. The stale pointers eventually cause use-after-free or double free in later code paths. Zeroing out all pointer fields after freeing to eliminate these stale pointers.

References

• https://git.kernel.org/stable/c/0ceadb5a3e45f1b81cf54bd496b40a5e50b6bd40
• https://git.kernel.org/stable/c/b610758bb3e0674644c1255cdafc2f46b7e05ff9
• https://git.kernel.org/stable/c/6613f36a2fa5c69e528bccba8b3d831f759dad2f
• https://git.kernel.org/stable/c/9a8aadcf0b459c1257b9477fd6402e1d5952ae07