[PATCH v18 19/25] x86/sgx: Add provisioning
Jarkko Sakkinen
jarkko.sakkinen at linux.intel.com
Fri Dec 21 23:11:48 UTC 2018
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;
};
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, ¶ms);
Cc: James Morris <jmorris at namei.org>
Cc: Serge E. Hallyn <serge at hallyn.com>
Cc: linux-security-module at vger.kernel.org
Suggested-by: Andy Lutomirski <luto at kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>
---
arch/x86/include/uapi/asm/sgx.h | 13 +++++++
arch/x86/kernel/cpu/sgx/driver/Makefile | 2 +-
arch/x86/kernel/cpu/sgx/driver/driver.h | 5 +++
arch/x86/kernel/cpu/sgx/driver/fs.c | 49 +++++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/driver/ioctl.c | 43 ++++++++++++++++++++++
arch/x86/kernel/cpu/sgx/driver/main.c | 7 ++++
6 files changed, 118 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/kernel/cpu/sgx/driver/fs.c
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/Makefile b/arch/x86/kernel/cpu/sgx/driver/Makefile
index 2bd952cc8a65..0325de93d605 100644
--- a/arch/x86/kernel/cpu/sgx/driver/Makefile
+++ b/arch/x86/kernel/cpu/sgx/driver/Makefile
@@ -1,2 +1,2 @@
obj-$(CONFIG_INTEL_SGX) += sgx.o
-sgx-$(CONFIG_INTEL_SGX) += encl.o ioctl.o main.o pte.o vma.o
+sgx-$(CONFIG_INTEL_SGX) += encl.o fs.o ioctl.o main.o pte.o vma.o
diff --git a/arch/x86/kernel/cpu/sgx/driver/driver.h b/arch/x86/kernel/cpu/sgx/driver/driver.h
index c9e40e090c58..e3487a077b6c 100644
--- a/arch/x86/kernel/cpu/sgx/driver/driver.h
+++ b/arch/x86/kernel/cpu/sgx/driver/driver.h
@@ -167,4 +167,9 @@ struct sgx_encl_page *sgx_fault_page(struct vm_area_struct *vma,
int sgx_test_and_clear_young(struct sgx_encl_page *page);
void sgx_flush_cpus(struct sgx_encl *encl);
+extern const struct file_operations sgx_fs_provision_fops;
+
+int sgx_fs_init(struct device *dev);
+void sgx_fs_remove(void);
+
#endif /* __ARCH_X86_INTEL_SGX_H__ */
diff --git a/arch/x86/kernel/cpu/sgx/driver/fs.c b/arch/x86/kernel/cpu/sgx/driver/fs.c
new file mode 100644
index 000000000000..b36b62a9cafb
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/driver/fs.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <linux/acpi.h>
+#include <linux/cdev.h>
+#include <linux/platform_device.h>
+#include <linux/security.h>
+#include <linux/suspend.h>
+#include <asm/traps.h>
+#include "driver.h"
+
+const struct file_operations sgx_fs_provision_fops;
+
+static struct dentry *sgx_fs;
+static struct dentry *sgx_fs_provision;
+
+int sgx_fs_init(struct device *dev)
+{
+ int ret;
+
+ sgx_fs = securityfs_create_dir(dev_name(dev), NULL);
+ if (IS_ERR(sgx_fs)) {
+ ret = PTR_ERR(sgx_fs);
+ goto err_sgx_fs;
+ }
+
+ sgx_fs_provision = securityfs_create_file("provision", 0600, sgx_fs,
+ NULL, &sgx_fs_provision_fops);
+ if (IS_ERR(sgx_fs)) {
+ ret = PTR_ERR(sgx_fs_provision);
+ goto err_sgx_fs_provision;
+ }
+
+ return 0;
+
+err_sgx_fs_provision:
+ securityfs_remove(sgx_fs);
+ sgx_fs_provision = NULL;
+
+err_sgx_fs:
+ sgx_fs = NULL;
+ return ret;
+}
+
+void sgx_fs_remove(void)
+{
+ securityfs_remove(sgx_fs_provision);
+ securityfs_remove(sgx_fs);
+}
diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
index 3a712950e116..d249a4329116 100644
--- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
@@ -193,6 +193,46 @@ 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.
+ *
+ * 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)
+ 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->attributes |= SGX_ATTR_PROVISIONKEY;
+ kref_put(&encl->refcount, sgx_encl_release);
+
+out:
+ fput(attribute_file);
+ return ret;
+}
+
typedef long (*sgx_ioc_t)(struct file *filep, unsigned int cmd,
unsigned long arg);
@@ -212,6 +252,9 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
case SGX_IOC_ENCLAVE_INIT:
handler = sgx_ioc_enclave_init;
break;
+ case SGX_IOC_ENCLAVE_SET_ATTRIBUTE:
+ handler = sgx_ioc_enclave_set_attribute;
+ break;
default:
return -ENOIOCTLCMD;
}
diff --git a/arch/x86/kernel/cpu/sgx/driver/main.c b/arch/x86/kernel/cpu/sgx/driver/main.c
index 19280863d703..ba125365a0d3 100644
--- a/arch/x86/kernel/cpu/sgx/driver/main.c
+++ b/arch/x86/kernel/cpu/sgx/driver/main.c
@@ -172,6 +172,10 @@ static int sgx_drv_init(struct device *parent)
if (!sgx_encl_wq)
return -ENOMEM;
+ ret = sgx_fs_init(&sgx_dev->ctrl_dev);
+ if (ret)
+ goto err_fs_init;
+
ret = cdev_device_add(&sgx_dev->ctrl_cdev, &sgx_dev->ctrl_dev);
if (ret)
goto err_device_add;
@@ -179,6 +183,9 @@ static int sgx_drv_init(struct device *parent)
return 0;
err_device_add:
+ sgx_fs_remove();
+
+err_fs_init:
destroy_workqueue(sgx_encl_wq);
return ret;
}
--
2.19.1
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