bpf: add check for invalid name in btf_name_valid_section()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: bpf: add check for invalid name in btf_name_valid_section() If the length of the name string is 1 and the value of name[0] is NULL byte, an OOB vulnerability occurs in btf_name_valid_section() and the return value is true, so the invalid name passes the check. To solve this, you need to check if the first position is NULL byte and if the first character is printable.

References

• https://git.kernel.org/stable/c/c8ffe2d4d37a05ce18c71b87421443c16f8475e5
• https://git.kernel.org/stable/c/bb6705c3f93bed2af03d43691743d4c43e3c8e6f