commit 81bbcff0c0 upstream.
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.
Fixes: b7fb4d78a6 ("RISC-V: use memcpy for kexec_file mode")
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/kexec/CAO7dBbVftLUhd2qrh7hmijTB3PEPfZAhykCGqEfrPoOcSrrj-w@mail.gmail.com/
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Signed-off-by: Tao Liu <ltao@redhat.com>
Link: https://patch.msgid.link/20260705232706.30265-2-ltao@redhat.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
606cc45e87