CVE-2024-49850

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> bpf: correctly handle malformed BPF_CORE_TYPE_ID_LOCAL relos<br /> <br /> In case of malformed relocation record of kind BPF_CORE_TYPE_ID_LOCAL<br /> referencing a non-existing BTF type, function bpf_core_calc_relo_insn<br /> would cause a null pointer deference.<br /> <br /> Fix this by adding a proper check upper in call stack, as malformed<br /> relocation records could be passed from user space.<br /> <br /> Simplest reproducer is a program:<br /> <br /> r0 = 0<br /> exit<br /> <br /> With a single relocation record:<br /> <br /> .insn_off = 0, /* patch first instruction */<br /> .type_id = 100500, /* this type id does not exist */<br /> .access_str_off = 6, /* offset of string "0" */<br /> .kind = BPF_CORE_TYPE_ID_LOCAL,<br /> <br /> See the link for original reproducer or next commit for a test case.