Subject: + init-do_mounts_rdc-fix-null-pointer-dereference-while-loading-initramfs.patch added to -mm tree
To: prasad@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 09 Oct 2013 14:48:57 -0700
The patch titled
Subject: init/do_mounts_rd.c: fix NULL pointer dereference while loading initramfs
has been added to the -mm tree. Its filename is
init-do_mounts_rdc-fix-null-pointer-dereference-while-loading-initramfs.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/init-do_mounts_rdc-fix-null-pointer-dereference-while-loading-initramfs.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/init-do_mounts_rdc-fix-null-pointer-dereference-while-loading-initramfs.patch
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From: P J P <prasad@xxxxxxxxxx>
Subject: init/do_mounts_rd.c: fix NULL pointer dereference while loading initramfs
Make menuconfig allows one to choose compression format of an initial
ramdisk image. But this choice does not result in duly compressed initial
ramdisk image. Because - $ make install - does not pass on the selected
compression choice to the dracut(8) tool, which creates the initramfs
file. dracut(8) generates the image with the default compression, ie.
gzip(1).
If a user chose any other compression instead of gzip(1), it leads to a
crash due to NULL pointer dereference in crd_load(), caused by a NULL
function pointer returned by the 'decompress_method()' routine. Because
the initramfs image is gzip(1) compressed, whereas the kernel knows only
to decompress the chosen format and not gzip(1).
This patch replaces the crash by an explicit panic() call with an
appropriate error message. This shall prevent the kernel from
eventually panicking in: init/do_mounts.c: mount_block_root() with
-> panic("VFS: Unable to mount root fs on %s", b);
Signed-off-by: P J P <prasad@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/do_mounts_rd.c | 7 +++++++
1 file changed, 7 insertions(+)
diff -puN init/do_mounts_rd.c~init-do_mounts_rdc-fix-null-pointer-dereference-while-loading-initramfs init/do_mounts_rd.c
--- a/init/do_mounts_rd.c~init-do_mounts_rdc-fix-null-pointer-dereference-while-loading-initramfs
+++ a/init/do_mounts_rd.c
@@ -342,6 +342,13 @@ static int __init crd_load(int in_fd, in
int result;
crd_infd = in_fd;
crd_outfd = out_fd;
+
+ if (!deco) {
+ pr_emerg("Invalid decompression routine: %p; "
+ "Select appropriate config option.\n", deco);
+ panic("Could not decompress initial ramdisk image.");
+ }
+
result = deco(NULL, 0, compr_fill, compr_flush, NULL, NULL, error);
if (decompress_error)
result = 1;
_
Patches currently in -mm which might be from prasad@xxxxxxxxxx are
init-do_mounts_rdc-fix-null-pointer-dereference-while-loading-initramfs.patch
init-do_mounts_rdc-fix-null-pointer-dereference-while-loading-initramfs-fix.patch
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