Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1400915

Re: SHA1-MB algorithm broken on latest kernel

Show all headers | View raw

On Fri, 2016-05-13 at 07:51 +0200, Ingo Molnar wrote:
> * Herbert Xu <herbert@gondor.apana.org.au> wrote:
> 
> > On Thu, May 12, 2016 at 04:31:06PM -0700, Megha Dey wrote:
> > > Hi,
> > >  
> > > When booting latest kernel with the CONFIG_CRYPTO_SHA1_MB enabled, I
> > > observe a panic.
> > >  
> > > After having a quick look, on reverting the following patches, I am able
> > > to complete the booting process.
> > > aec4d0e301f17bb143341c82cc44685b8af0b945
> > > 8691ccd764f9ecc69a6812dfe76214c86ac9ba06
> > > 68874ac3304ade7ed5ebb12af00d6b9bbbca0a16
> > >  
> > > Of the 3 patches, aec4d0e301f17bb143341c82cc44685b8af0b945 seems wrong.
> > > The r10 to r15 registers are used in sha1_x8_avx2.S, which is called
> > > from sha1_mb_mgr_flush_avx2.S.
> > >
> > > I do not think the functionality of the SHA1-MB crypto algorithm has
> > > been tested after applying these changes. (I am not sure if any of the
> > > other crypto algorithms have been affected by these changes).
> > 
> > Josh, Ingo:
> > 
> > Any ideas on this? Should we revert?
> 
> Yeah, I think so - although another option would be to standardize sha1_x8_avx2() 
> - the problem is that it is a function that clobbers registers without 
> saving/restoring them, breaking the C function ABI. I realize it's written in 
> assembly, but unless there are strong performance reasons to deviate from the 
> regular calling convention it might make sense to fix that.
> 
> Do any warnings get generated after the revert, if you enable 
> CONFIG_STACK_VALIDATION=y?

After the revert and enabling CONFIG_STACK_VALIDATION:
arch/x86/crypto/sha1-mb/sha1_mb_mgr_flush_avx2.o: warning: objtool:
sha1_mb_mgr_flush_avx2()+0x20d: call without frame pointer save/setup

arch/x86/crypto/sha1-mb/sha1_mb_mgr_submit_avx2.o: warning: objtool:
sha1_mb_mgr_submit_avx2()+0x115: call without frame pointer save/setup

> 
> Thanks,
> 
> 	Ingo

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

SHA1-MB algorithm broken on latest kernel Megha Dey <megha.dey@linux.intel.com> - 2016-05-13 01:30 +0200
  Re: SHA1-MB algorithm broken on latest kernel Herbert Xu <herbert@gondor.apana.org.au> - 2016-05-13 05:20 +0200
    Re: SHA1-MB algorithm broken on latest kernel Ingo Molnar <mingo@kernel.org> - 2016-05-13 08:00 +0200
      Re: SHA1-MB algorithm broken on latest kernel Megha Dey <megha.dey@linux.intel.com> - 2016-05-13 19:30 +0200
        Re: SHA1-MB algorithm broken on latest kernel Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-16 16:50 +0200
          Re: SHA1-MB algorithm broken on latest kernel Megha Dey <megha.dey@linux.intel.com> - 2016-05-16 20:30 +0200
            [PATCH] crypto/sha1-mb: make sha1_x8_avx2() conform to C function ABI Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-16 22:20 +0200
              Re: [PATCH] crypto/sha1-mb: make sha1_x8_avx2() conform to C  function ABI Megha Dey <megha.dey@linux.intel.com> - 2016-05-16 23:40 +0200
                Re: [PATCH] crypto/sha1-mb: make sha1_x8_avx2() conform to C  function ABI Josh Poimboeuf <jpoimboe@redhat.com> - 2016-05-16 23:50 +0200
                Re: [PATCH] crypto/sha1-mb: make sha1_x8_avx2() conform to C  function ABI Megha Dey <megha.dey@linux.intel.com> - 2016-05-17 01:10 +0200
                Re: [PATCH] crypto/sha1-mb: make sha1_x8_avx2() conform to C  function ABI Herbert Xu <herbert@gondor.apana.org.au> - 2016-05-17 08:40 +0200

csiph-web