From da028e4c4b0279eb49f80220d8f7cc62b4a57ccb Mon Sep 17 00:00:00 2001
From: David Disseldorp <ddiss@suse.de>
Date: Mon, 9 May 2022 18:29:19 -0700
Subject: [PATCH] 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(-)
diff --git a/init/initramfs.c b/init/initramfs.c
index 2f3d96dc3db6..2f79b3ec0b40 100644
--- a/init/initramfs.c
+++ b/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);