Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
riscv: Prevent NULL pointer dereference in machine_kexec_prepare()
A NULL pointer dereference issue is noticed in riscv’s machine_kexec_prepare(), where image->segment[i].buf might be NULL and copied unchecked.
The NULL buf comes from ima_add_kexec_buffer(), where kbuf is added by kexec_add_buffer(), but kbuf.buffer is NULL, then it is copied without a check in machine_kexec_prepare():
kexec_file_load -> kimage_file_alloc_init() -> kimage_file_prepare_segments() -> ima_add_kexec_buffer() -> kexec_add_buffer() -> machine_kexec_prepare() -> memcpy()
Address this by adding a check before the data copy attempt.
Details
- Affected product:
- Debian 10 ELS
- Affected packages:
- linux @ 4.19.0