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 riscvs 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.
References
- https://git.kernel.org/stable/c/606cc45e871e34b80a2f63874f069387a5b44176
- https://git.kernel.org/stable/c/6ad6954492697681ebcfc1beb0eb384406cd4b65
- https://git.kernel.org/stable/c/81bbcff0c053c4f5c711c31a9b72fc492bd96c3f
- https://git.kernel.org/stable/c/b5f92cc4e24a298bf390b0b189a4b888c0900161
- https://git.kernel.org/stable/c/c462e15497dc40abe369b3be7a2c91ac5d1be6f9
- https://git.kernel.org/stable/c/d5b2752a17efc165793ae38f2c24b5ed9c04ffde
- https://git.kernel.org/stable/c/eadd0c2c76aee6a738f17f251434c77db3c606c8