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From: "Huang, Kai" <kai.huang@intel.com>
To: "jarkko.sakkinen@linux.intel.com"
	<jarkko.sakkinen@linux.intel.com>,
	"Christopherson, Sean J" <sean.j.christopherson@intel.com>
Cc: "Svahn, Kai" <kai.svahn@intel.com>,
	"nhorman@redhat.com" <nhorman@redhat.com>,
	"jmorris@namei.org" <jmorris@namei.org>,
	"rientjes@google.com" <rientjes@google.com>,
	"josh@joshtriplett.org" <josh@joshtriplett.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"Ayoun, Serge" <serge.ayoun@intel.com>,
	"Huang, Haitao" <haitao.huang@intel.com>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"npmccallum@redhat.com" <npmccallum@redhat.com>,
	"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
	"luto@kernel.org" <luto@kernel.org>,
	"Katz-zamir, Shay" <shay.katz-zamir@intel.com>,
	"Hansen, Dave" <dave.hansen@intel.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"serge@hallyn.com" <serge@hallyn.com>,
	"andriy.shevchenko@linux.intel.com" 
	<andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH v19 17/27] x86/sgx: Add provisioning
Date: Thu, 21 Mar 2019 02:08:36 +0000
Message-ID: <1553134108.1952.4.camel@intel.com> (raw)
In-Reply-To: <20190319200912.GH25575@linux.intel.com>

On Tue, 2019-03-19 at 13:09 -0700, Sean Christopherson wrote:
> On Sun, Mar 17, 2019 at 11:14:46PM +0200, Jarkko Sakkinen wrote:
> > In order to provide a mechanism for devilering provisoning rights:
> > 
> > 1. Add a new file to the securityfs file called sgx/provision that works
> >    as a token for allowing an enclave to have the provisioning privileges.
> > 2. Add a new ioctl called SGX_IOC_ENCLAVE_SET_ATTRIBUTE that accepts the
> >    following data structure:
> > 
> >    struct sgx_enclave_set_attribute {
> >            __u64 addr;
> >            __u64 token_fd;
> >    };

Would you elaborate why the name is "token_fd"? I think *token* in SGX has more specific meaning?

> > 
> > A daemon could sit on top of sgx/provision and send a file descriptor of
> > this file to a process that needs to be able to provision enclaves.
> > 
> > The way this API is used is more or less straight-forward. Lets assume that
> > dev_fd is a handle to /dev/sgx and prov_fd is a handle to sgx/provision.
> > You would allow SGX_IOC_ENCLAVE_CREATE to initialize an enclave with the
> > PROVISIONKEY attribute by
> > 
> > params.addr = <enclave address>;
> > params.token_fd = prov_fd;
> > 
> > ioctl(dev_fd, SGX_IOC_ENCLAVE_SET_ATTRIBUTE, &params);
> > 
> > Cc: James Morris <jmorris@namei.org>
> > Cc: Serge E. Hallyn <serge@hallyn.com>
> > Cc: linux-security-module@vger.kernel.org
> > Suggested-by: Andy Lutomirski <luto@kernel.org>
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > ---
> >  arch/x86/include/uapi/asm/sgx.h        | 13 +++++++
> >  arch/x86/kernel/cpu/sgx/driver/ioctl.c | 43 +++++++++++++++++++++++
> >  arch/x86/kernel/cpu/sgx/driver/main.c  | 47 ++++++++++++++++++++++++++
> >  3 files changed, 103 insertions(+)
> > 
> > diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
> > index aadf9c76e360..150a784db395 100644
> > --- a/arch/x86/include/uapi/asm/sgx.h
> > +++ b/arch/x86/include/uapi/asm/sgx.h
> > @@ -16,6 +16,8 @@
> >  	_IOW(SGX_MAGIC, 0x01, struct sgx_enclave_add_page)
> >  #define SGX_IOC_ENCLAVE_INIT \
> >  	_IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
> > +#define SGX_IOC_ENCLAVE_SET_ATTRIBUTE \
> > +	_IOW(SGX_MAGIC, 0x03, struct sgx_enclave_set_attribute)
> >  
> >  /* IOCTL return values */
> >  #define SGX_POWER_LOST_ENCLAVE		0x40000000
> > @@ -56,4 +58,15 @@ struct sgx_enclave_init {
> >  	__u64	sigstruct;
> >  };
> >  
> > +/**
> > + * struct sgx_enclave_set_attribute - parameter structure for the
> > + *				      %SGX_IOC_ENCLAVE_INIT ioctl
> > + * @addr:		address within the ELRANGE
> > + * @attribute_fd:	file handle of the attribute file in the securityfs
> > + */
> > +struct sgx_enclave_set_attribute {
> > +	__u64	addr;
> > +	__u64	attribute_fd;
> > +};
> > +
> >  #endif /* _UAPI_ASM_X86_SGX_H */
> > diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> > index 4b9a91b53b50..5d85bd3f7876 100644
> > --- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> > +++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
> > @@ -759,6 +759,46 @@ static long sgx_ioc_enclave_init(struct file *filep, unsigned int cmd,
> >  	return ret;
> >  }
> >  
> > +/**
> > + * sgx_ioc_enclave_set_attribute - handler for %SGX_IOC_ENCLAVE_SET_ATTRIBUTE
> > + * @filep:	open file to /dev/sgx
> > + * @cmd:	the command value
> > + * @arg:	pointer to a struct sgx_enclave_set_attribute instance
> > + *
> > + * Sets an attribute matching the attribute file that is pointed by the
> > + * parameter structure field attribute_fd.
> 
> With the @data change (see below), this becomes something like:
> 
>  * Allow the enclave to request the attribute managed by the SGX security file
>  * pointed at by the parameter structure field attribute_fd.
> 
> > + *
> > + * Return: 0 on success, -errno otherwise
> > + */
> > +static long sgx_ioc_enclave_set_attribute(struct file *filep, unsigned int cmd,
> > +					  unsigned long arg)
> > +{
> > +	struct sgx_enclave_set_attribute *params = (void *)arg;
> > +	struct file *attribute_file;
> > +	struct sgx_encl *encl;
> > +	int ret;
> > +
> > +	attribute_file = fget(params->attribute_fd);
> > +	if (!attribute_file->f_op)
> 
> This should be:
> 
> 	if (!attribute_file)
> 		return -EINVAL;
> 
> > +		return -EINVAL;
> > +
> > +	if (attribute_file->f_op != &sgx_fs_provision_fops) {
> > +		ret = -EINVAL;
> > +		goto out;
> > +	}
> > +
> > +	ret = sgx_encl_get(params->addr, &encl);
> > +	if (ret)
> > +		goto out;
> > +
> > +	encl->allowed_attributes |= SGX_ATTR_PROVISIONKEY;
> 
> A cleanr approach would be to pass SGX_ATTR_PROVISIONKEY via @data to
> securityfs_create_file().  Then you don't need to define dummy file_ops
> for each file, i.e. a generic sgx_sec_fs_ops would suffice for the above
> check.  And you don't have this weird hardcoding of the provision bit.
> 
> E.g.:
> 
> 	if (attribute_file->f_op != &sgx_sec_fs_fops) {
> 		ret = -EINVAL;
> 		goto out;
> 	}
> 
> 	ret = sgx_encl_get(params->addr, &encl);
> 	if (ret)
> 		goto out;
> 
> 	encl->allowed_attributes |= (u64)attribute_file->private_data;
> 
> Since SGX doesn't support 32-bit builds we don't even need to worry about
> the (very distant) future where SGX defines bits in the 63:32 range.
> 

Agree with Sean that passing SGX_ATTR_PROVISIONKEY via @data is more cleaner.

Thanks,
-Kai

  reply index

Thread overview: 92+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-17 21:14 [PATCH v19 00/27] Intel SGX1 support Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 01/27] x86/cpufeatures: Add Intel-defined SGX feature bit Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 02/27] x86/cpufeatures: Add SGX sub-features (as Linux-defined bits) Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 03/27] x86/msr: Add IA32_FEATURE_CONTROL.SGX_ENABLE definition Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 04/27] x86/cpufeatures: Add Intel-defined SGX_LC feature bit Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 05/27] x86/msr: Add SGX Launch Control MSR definitions Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 06/27] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 07/27] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX Jarkko Sakkinen
2019-03-18 17:15   ` Dave Hansen
2019-03-18 19:53     ` Sean Christopherson
2019-03-17 21:14 ` [PATCH v19 08/27] x86/cpu/intel: Detect SGX support and update caps appropriately Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 09/27] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 10/27] x86/sgx: Add SGX1 and SGX2 architectural data structures Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 11/27] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 12/27] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2019-03-18 19:50   ` Sean Christopherson
2019-03-21 14:40     ` Jarkko Sakkinen
2019-03-21 15:28       ` Sean Christopherson
2019-03-22 10:19         ` Jarkko Sakkinen
2019-03-22 10:50           ` Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 13/27] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2019-03-19 19:59   ` Sean Christopherson
2019-03-21 14:51     ` Jarkko Sakkinen
2019-03-21 15:40       ` Sean Christopherson
2019-03-22 11:00         ` Jarkko Sakkinen
2019-03-22 16:43           ` Sean Christopherson
2019-03-17 21:14 ` [PATCH v19 16/27] x86/sgx: Add the Linux SGX Enclave Driver Jarkko Sakkinen
2019-03-19 21:19   ` Sean Christopherson
2019-03-21 15:51     ` Jarkko Sakkinen
2019-03-21 16:47       ` Sean Christopherson
2019-03-22 11:10         ` Jarkko Sakkinen
2019-03-26 13:26       ` Jarkko Sakkinen
2019-03-26 23:58         ` Sean Christopherson
2019-03-27  5:28           ` Jarkko Sakkinen
2019-03-27 17:57             ` Sean Christopherson
2019-03-27 18:38             ` Jethro Beekman
2019-03-27 20:06               ` Sean Christopherson
2019-03-28  1:21                 ` Jethro Beekman
2019-03-28 13:19                 ` Jarkko Sakkinen
2019-03-28 19:05                   ` Andy Lutomirski
2019-03-29  9:43                     ` Jarkko Sakkinen
2019-03-29 16:20                     ` Sean Christopherson
2019-04-01 10:01                       ` Jarkko Sakkinen
2019-04-01 17:25                         ` Jethro Beekman
2019-04-01 22:57                           ` Jarkko Sakkinen
2019-03-28 13:15               ` Jarkko Sakkinen
2019-03-19 23:00   ` Sean Christopherson
2019-03-21 16:18     ` Jarkko Sakkinen
2019-03-21 17:38       ` Sean Christopherson
2019-03-22 11:17         ` Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 17/27] x86/sgx: Add provisioning Jarkko Sakkinen
2019-03-19 20:09   ` Sean Christopherson
2019-03-21  2:08     ` Huang, Kai [this message]
2019-03-21 14:32       ` Jarkko Sakkinen
2019-03-21 21:41         ` Huang, Kai
2019-03-22 11:31           ` Jarkko Sakkinen
2019-03-21 14:30     ` Jarkko Sakkinen
2019-03-21 14:38   ` Nathaniel McCallum
2019-03-22 11:22     ` Jarkko Sakkinen
2019-03-21 16:50   ` Andy Lutomirski
2019-03-22 11:29     ` Jarkko Sakkinen
2019-03-22 11:43       ` Jarkko Sakkinen
2019-03-22 18:20         ` Andy Lutomirski
2019-03-25 14:55           ` Jarkko Sakkinen
2019-03-27  0:14             ` Sean Christopherson
2019-04-05 10:18             ` Jarkko Sakkinen
2019-04-05 13:53               ` Andy Lutomirski
2019-04-05 14:20                 ` Jarkko Sakkinen
2019-04-05 14:34                   ` Greg KH
2019-04-09 13:37                     ` Jarkko Sakkinen
2019-04-05 14:21                 ` Greg KH
2019-03-17 21:14 ` [PATCH v19 19/27] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2019-03-19 22:22   ` Sean Christopherson
2019-03-21 15:02     ` Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 20/27] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 21/27] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 22/27] x86/fault: Attempt to fixup unhandled #PF in vDSO before signaling Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 23/27] x86/traps: Attempt to fixup exceptions " Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 25/27] x86/sgx: SGX documentation Jarkko Sakkinen
2019-03-20 17:14   ` Sean Christopherson
2019-03-21 16:24     ` Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 26/27] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 27/27] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2019-03-19 17:12   ` Sean Christopherson
2019-03-21 14:42     ` Jarkko Sakkinen
     [not found] ` <20190317211456.13927-19-jarkko.sakkinen@linux.intel.com>
2019-03-19 22:09   ` [PATCH v19 18/27] x86/sgx: Add swapping code to the core and SGX driver Sean Christopherson
2019-03-21 14:59     ` Jarkko Sakkinen
2019-03-19 23:41 ` [PATCH v19 00/27] Intel SGX1 support Sean Christopherson
2019-03-19 23:52   ` Jethro Beekman
2019-03-20  0:22     ` Sean Christopherson
2019-03-21 16:20     ` Jarkko Sakkinen
2019-03-21 16:00   ` Jarkko Sakkinen

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