+ initramfs-refactor-do_header-cpio-magic-checks.patch added to -mm tree

+ initramfs-refactor-do_header-cpio-magic-checks.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: initramfs: refactor do_header() cpio magic checks
has been added to the -mm tree.  Its filename is
     initramfs-refactor-do_header-cpio-magic-checks.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/initramfs-refactor-do_header-cpio-magic-checks.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/initramfs-refactor-do_header-cpio-magic-checks.patch

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------------------------------------------------------
From: David Disseldorp <ddiss@suse.de>
Subject: 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: David Disseldorp <ddiss@suse.de>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 init/initramfs.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

--- a/init/initramfs.c~initramfs-refactor-do_header-cpio-magic-checks
+++ a/init/initramfs.c
@@ -257,12 +257,11 @@ 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)) {
-		error("no cpio magic");
+		if (memcmp(collected, "070707", 6) == 0)
+			error("incorrect cpio method used: use -H newc option");
+		else
+			error("no cpio magic");
 		return 1;
 	}
 	parse_header(collected);
_

Patches currently in -mm which might be from ddiss@suse.de are

initramfs-refactor-do_header-cpio-magic-checks.patch
initramfs-make-dir_entryname-a-flexible-array-member.patch
initramfs-add-initramfs_preserve_mtime-kconfig-option.patch
gen_init_cpio-fix-short-read-file-handling.patch
gen_init_cpio-support-file-checksum-archiving.patch
initramfs-support-cpio-extraction-with-file-checksums.patch