linux-kernel - [PATCH 1/2] Fix NULL pointer dereference while loading initramfs

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Date:	Sun, 15 Sep 2013 14:33:53 +0530 (IST)
From:	P J P <ppandit@...hat.com>
To:	linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] Fix NULL pointer dereference while loading initramfs 

   Hello,

While building the 3.11 kernel recently, I bumped into this issue.

Menuconfig allows one to choose compression format of an initial ramdisk 
image. If we select any compression other than the default gzip(1), it leads 
to a NULL pointer dereference while loading the initramfs image, at boot up.

Because - $ make install - does not pass on the selected compression format to 
dracut(8) tool, it generates the initramfs file compressed with the default 
gzip(1) format. But the kernel knows only to decompress the chosen format.

The attached patch herein, replaces the crash by an explicit panic() call with 
an appropriate error message. It keeps the kernel from eventually panicking in 
init/do_mounts.c: mount_root_block() with an inaccurate error message and 
which also looses the earlier printk output that hints about the missing 
gzip(1) decompression support.
   -> panic("VFS: Unable to mount root fs on %s", b);

Could someone please review this patch?

Thank you.
--
Prasad J Pandit / Red Hat Security Response Team
DB7A 84C5 D3F9 7CD1 B5EB  C939 D048 7860 3655 602B
View attachment "0001-NULL-pointer-dereference-while-loading-initramfs.patch" of type "TEXT/PLAIN" (1832 bytes)