Hello all!!
thanks for taking a look at this patch!
On Tue, 23 Nov 2021, David Bauer wrote:
Date: Tue, 23 Nov 2021 12:20:08
From: David Bauer <m...@david-bauer.net>
To: Enrico Mioso <mrkiko...@gmail.com>
Cc: Christian Lamparter <chunk...@gmail.com>,
OpenWrt Development List <openwrt-devel@lists.openwrt.org>
Subject: Re: [PATCH] FritzBox-4040-UBOOT: Allow for easier devices recovery
Hello Enrico,
On 11/22/21 11:55, Enrico Mioso wrote:
When flashing a broken kernel, or an image where failsafe mode is no more
accessible, recoverying these devices can become needlessly painful.
Allow for easier recovery by unconditionally trying to get an initramfs
image over TFTP once before booting, thereby giving the user a chance to
sysupgrade to a working image.
As I've already explained, I don't like increasing the time necessary for the
device to boot.
I think there are some balances to be made here. Booting Windows doesn't take
less time, if access to a Windows installation is at all possible. :)
Also, introducig such a method on a 4040 does not make sense, as its NOR
flash can be rewritten
from EVA.
I am open to change this patch, but I think the feature is really needed here.
That being said, unconditionally requesting a bootable image over the network
is a security
risk in itself. NAND based ipq40xx boards from AVM also only allow
connections to their
bootloader on cold-boots for exactly this reason.
Good point. Still, implementing a push-button process would be a little bit
complicated for me. Any help would be greatly apreciated in this regard.
For example, if an attacker is able to create a kernel-panic, your patch
would enable him
to modify the router in case he is on the same network. A Pushbutton TFTP
procedure mitigates
this problem, as it depends on the attacker having physical access to the
device.
Recovery is - for all boards - possible using the AVM recovery tool or
manually patching the
U-Boot and sideloading via EVA. So a network request for a boot image raises
more problems than
it tries to solve.
Yes, sideloading is definitely an option, for sure. Still, I think we are being
too user unfriendly here for no good reason.
Maybe we can find a middleground here?
I don't think this patch is the ideal solution, but I think there should be an easier way
to recover a device, especially when it depends on "our" code.
Best
David
Signed-off-by: Enrico Mioso <mrkiko...@gmail.com>
CC: Christian Lamparter <chunk...@gmail.com>
CC: David Bauer <m...@david-bauer.net>
---
Reasons for this patch:
1 - There are situations where it can be nice to recover a device without
the AVM Recovery tool. In some cases the tool won't even be an option (as
far as I know, it exists only for Windows, or am I wrong?).
2 - Since the effort of creating a second-stage bootloader for these
devices has been carried out (thanks a lot for this!), I think it makes
sense to allow for things to be more friendly to developers and users.
Side effects:
When nandboot fails, there will be TWO tftp requests with no delay between
them, then the sleep will kick in.
Possible "improvements":
Implementing a push-button method may be preferred. Still, I have no easy
way to attach an UART to the device right now.
Moreover, being able to do this "more" remotely would be a vaulable feature
to me.
Enrico
include/configs/fritz1200.h | 2 +-
include/configs/fritz3000.h | 2 +-
include/configs/fritz4040.h | 2 +-
include/configs/fritz7530.h | 2 +-
4 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/configs/fritz1200.h b/include/configs/fritz1200.h
index 90d5186..16152a3 100644
--- a/include/configs/fritz1200.h
+++ b/include/configs/fritz1200.h
@@ -23,7 +23,7 @@
"mtdparts=" MTDPARTS_DEFAULT "\0" \
"nandboot=ubi part ubi && ubi read 0x85000000 kernel && bootm\0"
\
"tftpboot=tftpboot && bootm; sleep 5; run tftpboot\0" \
- "fritzboot=run nandboot || run tftpboot;\0" \
+ "fritzboot=tftpboot && bootm; run nandboot || run tftpboot;\0"
\
#undef V_PROMPT
#define V_PROMPT "(" CONFIG_MODEL ") # "
diff --git a/include/configs/fritz3000.h b/include/configs/fritz3000.h
index e383ffb..3440550 100644
--- a/include/configs/fritz3000.h
+++ b/include/configs/fritz3000.h
@@ -23,7 +23,7 @@
"mtdparts=" MTDPARTS_DEFAULT "\0" \
"nandboot=ubi part ubi && ubi read 0x85000000 kernel && bootm\0"
\
"tftpboot=tftpboot && bootm; sleep 5; run tftpboot\0" \
- "fritzboot=run nandboot || run tftpboot;\0" \
+ "fritzboot=tftpboot && bootm; run nandboot || run tftpboot;\0"
\
#undef V_PROMPT
#define V_PROMPT "(" CONFIG_MODEL ") # "
diff --git a/include/configs/fritz4040.h b/include/configs/fritz4040.h
index 060afb0..582edfd 100644
--- a/include/configs/fritz4040.h
+++ b/include/configs/fritz4040.h
@@ -23,7 +23,7 @@
"mtdparts=" MTDPARTS_DEFAULT "\0" \
"nandboot=nboot firmware && bootm\0" \
"tftpboot=tftpsrv && bootm; sleep 5; run tftpboot\0" \
- "fritzboot=run nandboot || run tftpboot;\0" \
+ "fritzboot=tftpboot && bootm; run nandboot || run tftpboot;\0"
\
#undef V_PROMPT
#define V_PROMPT "(" CONFIG_MODEL ") # "
diff --git a/include/configs/fritz7530.h b/include/configs/fritz7530.h
index b07ecfc..caecd5d 100644
--- a/include/configs/fritz7530.h
+++ b/include/configs/fritz7530.h
@@ -23,7 +23,7 @@
"mtdparts=" MTDPARTS_DEFAULT "\0" \
"nandboot=ubi part ubi && ubi read 0x85000000 kernel && bootm\0"
\
"tftpboot=tftpboot && bootm; sleep 5; run tftpboot\0" \
- "fritzboot=run nandboot || run tftpboot;\0" \
+ "fritzboot=tftpboot && bootm; run nandboot || run tftpboot;\0"
\
#undef V_PROMPT
#define V_PROMPT "(" CONFIG_MODEL ") # "
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