From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Wed, 6 May 2020 09:48:57 -0400 Subject: [PATCH V2] mkimage: fit: Do not tail-pad fitImage with external data In-Reply-To: <1073087038ce37a09715bcb5054c7931@walle.cc> References: <20200501154026.79169-1-marex@denx.de> <20200504112749.GE12564@bill-the-cat> <20200505175022.GW12564@bill-the-cat> <1073087038ce37a09715bcb5054c7931@walle.cc> Message-ID: <20200506134857.GE12564@bill-the-cat> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Tue, May 05, 2020 at 11:17:19PM +0200, Michael Walle wrote: > Hi all, > > Am 2020-05-05 20:41, schrieb Simon Glass: > > Hi Tom, > > > > On Tue, 5 May 2020 at 11:50, Tom Rini wrote: > > > > > > On Tue, May 05, 2020 at 06:39:58PM +0200, Marek Vasut wrote: > > > > On 5/5/20 6:37 PM, Alex Kiernan wrote: > > > > > On Tue, May 5, 2020 at 2:28 PM Marek Vasut wrote: > > > > >> > > > > >> On 5/5/20 3:22 PM, Alex Kiernan wrote: > > > > >>> On Mon, May 4, 2020 at 12:28 PM Tom Rini wrote: > > > > >>>> > > > > >>>> On Fri, May 01, 2020 at 05:40:25PM +0200, Marek Vasut wrote: > > > > >>>> > > > > >>>>> There is no reason to tail-pad fitImage with external data to 4-bytes, > > > > >>>>> while fitImage without external data does not have any such padding and > > > > >>>>> is often unaligned. DT spec also does not mandate any such padding. > > > > >>>>> > > > > >>>>> Moreover, the tail-pad fills the last few bytes with uninitialized data, > > > > >>>>> which could lead to a potential information leak. > > > > >>>>> > > > > >>>>> $ echo -n xy > /tmp/data ; \ > > > > >>>>> ./tools/mkimage -E -f auto -d /tmp/data /tmp/fitImage ; \ > > > > >>>>> hexdump -vC /tmp/fitImage | tail -n 3 > > > > >>>>> > > > > >>>>> before: > > > > >>>>> 00000260 61 2d 6f 66 66 73 65 74 00 64 61 74 61 2d 73 69 |a-offset.data-si| > > > > >>>>> 00000270 7a 65 00 00 78 79 64 64 |ze..xydd| > > > > >>>>> ^^ ^^ ^^ > > > > >>>>> after: > > > > >>>>> 00000260 61 2d 6f 66 66 73 65 74 00 64 61 74 61 2d 73 69 |a-offset.data-si| > > > > >>>>> 00000270 7a 65 00 78 79 |ze.xy| > > > > >>>>> > > > > >>>>> Signed-off-by: Marek Vasut > > > > >>>>> Reviewed-by: Simon Glass > > > > >>>>> Cc: Heinrich Schuchardt > > > > >>>>> Cc: Tom Rini > > > > >>>> > > > > >>>> Applied to u-boot/master, thanks! > > > > >>>> > > > > >>> > > > > >>> This breaks booting on my board (am3352, eMMC boot, FIT u-boot, > > > > >>> CONFIG_SPL_LOAD_FIT). Not got any useful diagnostics - if I boot it > > > > >>> from eMMC I get nothing at all on the console, if I boot over ymodem > > > > >>> it stalls at 420k, before continuing to 460k. My guess is there's some > > > > >>> error going to the console at the 420k mark, but obviously it's lost > > > > >>> in the ymodem... I have two DTBs in the FIT image, 420k would about > > > > >>> align to the point between them. > > > > >> > > > > >> My bet would be on some padding / unaligned access problem that this > > > > >> patch uncovered. Can you take a look ? > > > > > > > > > > Seems plausible. With this change my external data starts at 0x483 and > > > > > everything after it is non-aligned: > > > > > > > > Should the beginning of external data be aligned ? > > > > > > If in U-Boot we revert e8c2d25845c72c7202a628a97d45e31beea40668 does > > > the > > > problem go away? If so, that's not a fix outright, it means we need > > > to > > > dig back in to the libfdt thread and find the "make this work without > > > killing performance everywhere all the time" option. > > > > If it is a device tree, it must be 32-bit aligned. > > This commit actually breaks my board too (which I was just about to send > upstream, but realized it was broken). > > Said board uses SPL and main U-Boot. SPL runs fine and main u-boot doesn't > output anything. The only difference which I found is that fit-dtb.blob is > 2 bytes shorter. And the content is shifted by one byte although > data-offset is the same. Strange. In the non-working case, the inner > FDT magic isn't 4 byte aligned. > > You can find the two fit-dtb.blobs here: > > https://walle.cc/u-boot/fit-dtb.blob.working > https://walle.cc/u-boot/fit-dtb.blob.non-working > > > Reverting e8c2d25845c72c7202a628a97d45e31beea40668 doesn't help (I might > reverted it the wrong way, there is actually a conflict). > > I'll dig deeper into that tomorrow, but maybe you have some pointers where > to look. > > For reference you can find the current patch here: > https://github.com/mwalle/u-boot/tree/sl28-upstream I think we have a few things to fix here. Marek's patch is breaking things and needs to be reverted. But it's showing a few underlying problems that need to be fixed too: - fit_extract_data() needs to use calloc() not malloc() so that we don't leak random data. - We need to 8-byte alignment on the external data. That's the requirement for Linux for device trees on both 32 and 64bit arm. Atish, does RISC-V require more than that? I don't see it in Linux's Documentation/riscv/boot-image-header.rst (and there's no booting.rst file like arm/arm64). Thanks all! -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 659 bytes Desc: not available URL: