bpftool: Fix NULL pointer dereference when pin {PROG, MAP, LINK} without FILE

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: bpftool: Fix NULL pointer dereference when pin {PROG, MAP, LINK} without FILE When using bpftool to pin {PROG, MAP, LINK} without FILE, segmentation fault will occur. The reson is that the lack of FILE will cause strlen to trigger NULL pointer dereference. The corresponding stacktrace is shown below: do_pin do_pin_any do_pin_fd mount_bpffs_for_pin strlen(name) <- NULL pointer dereference Fix it by adding validation to the common process.

References

• https://git.kernel.org/stable/c/8c80b2fca4112d724dde477aed13f7b0510a2792
• https://git.kernel.org/stable/c/6dcdd1b68b7f9333d48d48fc77b75e7f235f6a4a
• https://git.kernel.org/stable/c/da5161ba94c5e9182c301dd4f09c94f715c068bd
• https://git.kernel.org/stable/c/34de8e6e0e1f66e431abf4123934a2581cb5f133