Bug 14041

Summary:	using modprobe/insmod with compressed modules gives scary kernel warnings
Product:	Busybox	Reporter:	nolange79
Component:	Other	Assignee:	unassigned
Status:	NEW ---
Severity:	normal	CC:	busybox-cvs
Priority:	P5
Version:	1.33.x
Target Milestone:	---
Hardware:	All
OS:	Linux
Host:		Target:
Build:

Description nolange79 2021-07-28 07:32:33 UTC

I am using kernel 5.4 on x86_64 fro an embedded system.

loading a compressed module will give the kernel log error:
kernel: Module has invalid ELF structures

steps to reproduce are simply:
# busybox insmod nbd.ko.gz

Some points:

this happens with gzip and xz

the util-linux insmod/modprobe work without log entry

the module seems correctly loaded and works.

decompressing the module (with the same busybox executable) and then loading it will lead to no log entry

# (after unloading the module again)
# busybox gzip -d nbd.ko.gz
# busybox insmod nbd.ko


I dont know if there is any functional issue, but I am tempted to raise severity since I cant rule it out either.

Comment 1 sylvain.prat 2022-02-01 18:48:38 UTC

I also fell into the problem. I was wondering how alpine linux worked out with compressed linux modules and I finally found out that they don't use busybox's modprobe anymore... Since the decompression methods already exist in busybox, it shouldn't be too hard to implement I guess, but I'm not competent enough to do it myself.