From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Walle Date: Tue, 05 May 2020 23:17:19 +0200 Subject: [PATCH V2] mkimage: fit: Do not tail-pad fitImage with external data In-Reply-To: References: <20200501154026.79169-1-marex@denx.de> <20200504112749.GE12564@bill-the-cat> <20200505175022.GW12564@bill-the-cat> Message-ID: <1073087038ce37a09715bcb5054c7931@walle.cc> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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 > > But Marek's patch affects the FIT image itself, so I am not sure what > would go after that. > > Regards, > Simon -- -michael