Linux · Linux Kernel · CVE-2021-47486
Name of the Vulnerable Software and Affected Versions:
Linux kernel (affected versions not specified)
Description:
The issue is related to a potential NULL dereference in the riscv, bpf components of the Linux kernel. This occurs when the RISC-V BPF JIT fails to converge in NR JIT ITERATIONS steps, resulting in `jit data->header` being NULL. The `bpf jit binary free()` function requires a non-NULL argument, and when this condition is not met, it triggers a NULL dereference. This could allow an attacker to cause a denial of service.
Recommendations:
To resolve the issue, check the argument prior to calling the `bpf jit binary free()` function to avoid the NULL dereference. As a temporary workaround, consider adding a check for `jit data->header` being NULL before calling `bpf jit binary free()` to prevent the NULL dereference. At the moment, there is no information about a newer version that contains a fix for this vulnerability.