From: Jan Beulich <jbeulich@suse.com> To: Ross Lagerwall <ross.lagerwall@citrix.com> Cc: xen-devel@lists.xenproject.org, Andrew Cooper <andrew.cooper3@citrix.com>, Daniel Kiper <daniel.kiper@oracle.com>, grub-devel@gnu.org Subject: Re: [PATCH 1/7] multiboot2: Add load type header and support for the PE binary type Date: Thu, 14 Mar 2024 15:33:01 +0100 [thread overview] Message-ID: <b9709a9e-841d-4dfa-ad40-db2a2ffde95c@suse.com> (raw) In-Reply-To: <CAG7k0EoHs7WZrgL4ixZWvfc1VUv40pQe=qt8WTLMdQhBv54ngA@mail.gmail.com> On 14.03.2024 15:24, Ross Lagerwall wrote: > On Thu, Mar 14, 2024 at 1:37 PM Jan Beulich <jbeulich@suse.com> wrote: >> On 14.03.2024 10:30, Ross Lagerwall wrote: >>> On Thu, Mar 14, 2024 at 7:24 AM Jan Beulich <jbeulich@suse.com> wrote: >>>> On 13.03.2024 16:07, Ross Lagerwall wrote: >>>>> In addition to the existing address and ELF load types, specify a new >>>>> optional PE binary load type. This new type is a useful addition since >>>>> PE binaries can be signed and verified (i.e. used with Secure Boot). >>>> >>>> And the consideration to have ELF signable (by whatever extension to >>>> the ELF spec) went nowhere? >>> >>> I'm not sure if you're referring to some ongoing work to create signable >>> ELFs that I'm not aware of. >> >> Something must have been invented already to make Linux modules signable. > > Linux module signatures operate outside of the ELF container. In fact, > AFAIK the actual signed content could be anything. The file format is: > > * Content (i.e. ELF binary) > * Signature of content in PKCS7 format > * Signature info, including signature length > * Magic marker: "~Module signature appended~\n" > > This kind of arrangement does indeed work but it is fragile. Since the > signature is on the entire contents and tools that understand ELF don't > parse the signature, any transformation of the binary (e.g. to > strip out debuginfo) will cause the signature to be lost / invalidated. This looks extremely poor to me, so ... > Nevertheless, this could still be an option for Xen if this is > deemed to be a preferred solution by others. It would be good to hear > some opinions on this. ... I'd rather not see this used for Xen. Jan
WARNING: multiple messages have this Message-ID (diff)
From: Jan Beulich via Grub-devel <grub-devel@gnu.org> To: Ross Lagerwall <ross.lagerwall@citrix.com> Cc: Jan Beulich <jbeulich@suse.com>, xen-devel@lists.xenproject.org, Andrew Cooper <andrew.cooper3@citrix.com>, Daniel Kiper <daniel.kiper@oracle.com>, grub-devel@gnu.org Subject: Re: [PATCH 1/7] multiboot2: Add load type header and support for the PE binary type Date: Thu, 14 Mar 2024 15:33:01 +0100 [thread overview] Message-ID: <b9709a9e-841d-4dfa-ad40-db2a2ffde95c@suse.com> (raw) In-Reply-To: <CAG7k0EoHs7WZrgL4ixZWvfc1VUv40pQe=qt8WTLMdQhBv54ngA@mail.gmail.com> On 14.03.2024 15:24, Ross Lagerwall wrote: > On Thu, Mar 14, 2024 at 1:37 PM Jan Beulich <jbeulich@suse.com> wrote: >> On 14.03.2024 10:30, Ross Lagerwall wrote: >>> On Thu, Mar 14, 2024 at 7:24 AM Jan Beulich <jbeulich@suse.com> wrote: >>>> On 13.03.2024 16:07, Ross Lagerwall wrote: >>>>> In addition to the existing address and ELF load types, specify a new >>>>> optional PE binary load type. This new type is a useful addition since >>>>> PE binaries can be signed and verified (i.e. used with Secure Boot). >>>> >>>> And the consideration to have ELF signable (by whatever extension to >>>> the ELF spec) went nowhere? >>> >>> I'm not sure if you're referring to some ongoing work to create signable >>> ELFs that I'm not aware of. >> >> Something must have been invented already to make Linux modules signable. > > Linux module signatures operate outside of the ELF container. In fact, > AFAIK the actual signed content could be anything. The file format is: > > * Content (i.e. ELF binary) > * Signature of content in PKCS7 format > * Signature info, including signature length > * Magic marker: "~Module signature appended~\n" > > This kind of arrangement does indeed work but it is fragile. Since the > signature is on the entire contents and tools that understand ELF don't > parse the signature, any transformation of the binary (e.g. to > strip out debuginfo) will cause the signature to be lost / invalidated. This looks extremely poor to me, so ... > Nevertheless, this could still be an option for Xen if this is > deemed to be a preferred solution by others. It would be good to hear > some opinions on this. ... I'd rather not see this used for Xen. Jan _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
next prev parent reply other threads:[~2024-03-14 14:33 UTC|newest] Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-13 15:07 [PATCH 0/7] GRUB: Supporting Secure Boot of xen.gz Ross Lagerwall 2024-03-13 15:07 ` Ross Lagerwall via Grub-devel 2024-03-13 15:07 ` [PATCH 1/7] multiboot2: Add load type header and support for the PE binary type Ross Lagerwall 2024-03-13 15:07 ` Ross Lagerwall via Grub-devel 2024-03-14 7:24 ` Jan Beulich 2024-03-14 7:24 ` Jan Beulich via Grub-devel 2024-03-14 8:12 ` Damien Zammit via Grub-devel 2024-03-14 8:12 ` Damien Zammit 2024-03-14 8:49 ` Vladimir 'phcoder' Serbinenko 2024-03-14 9:30 ` Ross Lagerwall 2024-03-14 9:30 ` Ross Lagerwall via Grub-devel 2024-03-14 13:37 ` Jan Beulich 2024-03-14 13:37 ` Jan Beulich via Grub-devel 2024-03-14 14:24 ` Ross Lagerwall 2024-03-14 14:24 ` Ross Lagerwall via Grub-devel 2024-03-14 14:33 ` Jan Beulich [this message] 2024-03-14 14:33 ` Jan Beulich via Grub-devel 2024-03-19 12:12 ` Roger Pau Monné 2024-03-19 12:12 ` Roger Pau Monné via Grub-devel 2024-03-19 13:18 ` Roger Pau Monné 2024-03-19 13:18 ` Roger Pau Monné via Grub-devel 2024-03-19 14:46 ` Ross Lagerwall 2024-03-19 14:46 ` Ross Lagerwall via Grub-devel 2024-03-20 11:04 ` Roger Pau Monné 2024-03-20 11:04 ` Roger Pau Monné via Grub-devel 2024-03-13 15:07 ` [PATCH 2/7] multiboot2: Allow 64-bit entry tags Ross Lagerwall 2024-03-13 15:07 ` Ross Lagerwall via Grub-devel 2024-03-19 10:07 ` Roger Pau Monné 2024-03-19 10:07 ` Roger Pau Monné via Grub-devel 2024-03-28 15:05 ` Ross Lagerwall 2024-03-28 15:05 ` Ross Lagerwall via Grub-devel 2024-03-28 15:41 ` Roger Pau Monné 2024-03-28 15:41 ` Roger Pau Monné via Grub-devel 2024-03-13 15:07 ` [PATCH 3/7] multiboot2: Add support for the load type header tag Ross Lagerwall 2024-03-13 15:07 ` Ross Lagerwall via Grub-devel 2024-03-15 7:30 ` Vladimir 'phcoder' Serbinenko 2024-03-15 7:30 ` Vladimir 'phcoder' Serbinenko 2024-03-28 14:58 ` Ross Lagerwall 2024-03-28 14:58 ` Ross Lagerwall via Grub-devel 2024-03-13 15:07 ` [PATCH 4/7] multiboot2: Add PE load support Ross Lagerwall 2024-03-13 15:07 ` Ross Lagerwall via Grub-devel 2024-03-13 15:07 ` [PATCH 5/7] multiboot2: Add support for 64-bit entry addresses Ross Lagerwall 2024-03-13 15:07 ` Ross Lagerwall via Grub-devel 2024-03-13 15:07 ` [PATCH 6/7] efi: Allow loading multiboot modules without verification Ross Lagerwall 2024-03-13 15:07 ` Ross Lagerwall via Grub-devel 2024-03-13 15:07 ` [PATCH 7/7] verifiers: Verify after decompression Ross Lagerwall 2024-03-13 15:07 ` Ross Lagerwall via Grub-devel 2024-03-15 3:50 ` Michael Chang 2024-03-15 3:50 ` Michael Chang via Grub-devel 2024-03-15 7:25 ` Vladimir 'phcoder' Serbinenko 2024-03-28 14:55 ` Ross Lagerwall via Grub-devel
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