On Tue, Mar 03, 2026 at 06:32:50AM -0700, Simon Glass wrote: > Hi, > > On Tue, 3 Mar 2026 at 01:09, Ahmad Fatoum <[email protected]> wrote: > > > > Hello Tom, > > > > On 3/2/26 23:09, Tom Rini wrote: > > > There is a flaw in how U-Boot verifies and generates signatures for FIT > > > images. To prevent mix and match style attacks, it is recommended to > > > use signed configurations. How this is supposed to work is documented in > > > doc/usage/fit/signature.rst. > > > > > > Crucially, the `hashed-nodes` property of the `signature` node contains > > > which nodes of the FIT device tree were hashed as part of the signature > > > and should be verified. However, this property itself is not part of the > > > hash and can therefore be modified by an attacker. Furthermore, the > > > signature only contains the name of each node and not the path in the > > > device tree to the node. > > > > > > This patch reworks the code to address this specific oversight. > > > > Do I understand correctly that this is a breaking change > > for FIT with signed configurations? > > > > - New U-Boot hashes more than intended for old FIT > > - Old U-Boot hashes less than intended for new FIT > > Yes, that's right. > > Reviewed-by: Simon Glass <[email protected]> > > I can see how this works. Please see nit below.
I did fail to run this past checkpatch.pl and will fixup when applying, thanks. -- Tom
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