Commit da028e4c authored by David Disseldorp's avatar David Disseldorp Committed by Andrew Morton
Browse files

initramfs: refactor do_header() cpio magic checks 

Patch series "initramfs: "crc" cpio format and INITRAMFS_PRESERVE_MTIME", v7.

This patchset does some minor initramfs refactoring and allows cpio entry
mtime preservation to be disabled via a new Kconfig
INITRAMFS_PRESERVE_MTIME option.

Patches 4/6 to 6/6 implement support for creation and extraction of "crc"
cpio archives, which carry file data checksums.  Basic tests for this
functionality can be found at https://github.com/rapido-linux/rapido/pull/163


This patch (of 6):

do_header() is called for each cpio entry and fails if the first six bytes
don't match "newc" magic.  The magic check includes a special case error
message if POSIX.1 ASCII (cpio -H odc) magic is detected.  This special
case POSIX.1 check can be nested under the "newc" mismatch code path to
avoid calling memcmp() twice in a non-error case.

Link: https://lkml.kernel.org/r/20220404093429.27570-1-ddiss@suse.de
Link: https://lkml.kernel.org/r/20220404093429.27570-2-ddiss@suse.de


Signed-off-by: default avatarDavid Disseldorp <ddiss@suse.de>
Reviewed-by: default avatarMartin Wilck <mwilck@suse.com>
Acked-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 70551977

init/initramfs.c

+4 −5
Original line number Diff line number Diff line
@@ -257,11 +257,10 @@ static int __init do_collect(void) 


static int __init do_header(void)

{

	if (memcmp(collected, "070707", 6)==0) {

		error("incorrect cpio method used: use -H newc option");

		return 1;

	}

	if (memcmp(collected, "070701", 6)) {

		if (memcmp(collected, "070707", 6) == 0)

			error("incorrect cpio method used: use -H newc option");

		else

			error("no cpio magic");

		return 1;

	}