Re: [PATCH] tpm: fix race condition in tpm_common_write()

Re: [PATCH] tpm: fix race condition in tpm_common_write()

[Jarkko Sakkinen]

On Tue, May 22, 2018 at 10:32:46AM -0700, Tadeusz Struk wrote:
> There is a race condition in tpm_common_write function allowing two
> threads on the same /dev/tpm<N>, or two different applications on
> the same /dev/tpmrm<N> to overwrite eachother requests/responses.
> 
> Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>

Ouch o_O Do you have a fixes tag for this one?

Thank you.

Reviewed-by: Jarkko Sakkien <jarkko.sakkinen@linux.intel.com>

/Jarkko

Re: [PATCH] tpm: fix race condition in tpm_common_write()

[Tadeusz Struk]

On 05/23/2018 06:23 AM, Jarkko Sakkinen wrote:
> Ouch o_O Do you have a fixes tag for this one?
> 

This one is quite tricky.
The original bug was introduced by abce9ac292e13 (tpm: Propagate error from tpm_transmit to fix a timeout hang)
and the code back then was in drivers/char/tpm/tpm-interface.c file

Then there were two other commits that moved the code around:
afdba32e2a9ea (tpm: Pull everything related to /dev/tpmX into tpm-dev.c)
which moved it from drivers/char/tpm/tpm-interface.c into drivers/char/tpm/tpm-dev.c

and last one, ecb38e2f521b0 (tpm: split out tpm-dev.c into tpm-dev.c and tpm-common-dev.c)
which moved it from drivers/char/tpm/tpm-dev.c into tpm-common-dev.c

I have no idea how to tag it. Maybe we can use:
Fixes: ecb38e2f521b0 ("tpm: split out tpm-dev.c into tpm-dev.c and tpm-common-dev.c")

And then it probably needs to be back ported manually all the way back to abce9ac292e13.

Thanks,
-- 
Tadeusz

Re: [PATCH] tpm: fix race condition in tpm_common_write()

[Jason Gunthorpe]

On Wed, May 23, 2018 at 10:57:07AM -0700, Tadeusz Struk wrote:
> On 05/23/2018 06:23 AM, Jarkko Sakkinen wrote:
> > Ouch o_O Do you have a fixes tag for this one?
> > 
> 
> This one is quite tricky.
> The original bug was introduced by abce9ac292e13 (tpm: Propagate error from tpm_transmit to fix a timeout hang)
> and the code back then was in drivers/char/tpm/tpm-interface.c file

No, it has been wrong since before git history started, so just use

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

All the other commits you listed are just moving the bad code around
to new files.

Jason

Re: [PATCH] tpm: fix race condition in tpm_common_write()

[Jarkko Sakkinen]

On Wed, May 23, 2018 at 10:57:07AM -0700, Tadeusz Struk wrote:
> On 05/23/2018 06:23 AM, Jarkko Sakkinen wrote:
> > Ouch o_O Do you have a fixes tag for this one?
> > 
> 
> This one is quite tricky.
> The original bug was introduced by abce9ac292e13 (tpm: Propagate error from tpm_transmit to fix a timeout hang)
> and the code back then was in drivers/char/tpm/tpm-interface.c file
> 
> Then there were two other commits that moved the code around:
> afdba32e2a9ea (tpm: Pull everything related to /dev/tpmX into tpm-dev.c)
> which moved it from drivers/char/tpm/tpm-interface.c into drivers/char/tpm/tpm-dev.c
> 
> and last one, ecb38e2f521b0 (tpm: split out tpm-dev.c into tpm-dev.c and tpm-common-dev.c)
> which moved it from drivers/char/tpm/tpm-dev.c into tpm-common-dev.c
> 
> I have no idea how to tag it. Maybe we can use:
> Fixes: ecb38e2f521b0 ("tpm: split out tpm-dev.c into tpm-dev.c and tpm-common-dev.c")
> 
> And then it probably needs to be back ported manually all the way back to abce9ac292e13.
> 
> Thanks,
> -- 
> Tadeusz

Thank you. I'll cc this to stable.

/Jarkko

Re: [PATCH] tpm: fix race condition in tpm_common_write()

[Jarkko Sakkinen]

On Wed, May 23, 2018 at 01:41:15PM -0600, Jason Gunthorpe wrote:
> On Wed, May 23, 2018 at 10:57:07AM -0700, Tadeusz Struk wrote:
> > On 05/23/2018 06:23 AM, Jarkko Sakkinen wrote:
> > > Ouch o_O Do you have a fixes tag for this one?
> > > 
> > 
> > This one is quite tricky.
> > The original bug was introduced by abce9ac292e13 (tpm: Propagate error from tpm_transmit to fix a timeout hang)
> > and the code back then was in drivers/char/tpm/tpm-interface.c file
> 
> No, it has been wrong since before git history started, so just use
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> 
> All the other commits you listed are just moving the bad code around
> to new files.
> 
> Jason

OK, thank you Jason. I'll use that.

/Jarkko