[PATCH v5 07/11] intel_sgx: ptrace() support

Jarkko Sakkinen
2017-11-13T19:46:09Z

Implemented VMA callbacks in order to ptrace() debug enclaves.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
drivers/platform/x86/intel_sgx/sgx_vma.c | 115 +++++++++++++++++++++++++++++++
1 file changed, 115 insertions(+)

diff --git a/drivers/platform/x86/intel_sgx/sgx_vma.c b/drivers/platform/x86/intel_sgx/sgx_vma.c
index 2b714daa6eb7..e447b5a9bb96 100644
--- a/drivers/platform/x86/intel_sgx/sgx_vma.c
+++ b/drivers/platform/x86/intel_sgx/sgx_vma.c
@@ -110,8 +110,123 @@ static int sgx_vma_fault(struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
}

+static inline int sgx_vma_access_word(struct sgx_encl *encl,
+ unsigned long addr,
+ void *buf,
+ int len,
+ int write,
+ struct sgx_encl_page *encl_page,
+ int i)
+{
+ char data[sizeof(unsigned long)];
+ int align, cnt, offset;
+ void *vaddr;
+ int ret;
+
+ offset = ((addr + i) & (PAGE_SIZE - 1)) & ~(sizeof(unsigned long) - 1);
+ align = (addr + i) & (sizeof(unsigned long) - 1);
+ cnt = sizeof(unsigned long) - align;
+ cnt = min(cnt, len - i);
+
+ if (write) {
+ if (encl_page->flags & SGX_ENCL_PAGE_TCS &&
+ (offset < 8 || (offset + (len - i)) > 16))
+ return -ECANCELED;
+
+ if (align || (cnt != sizeof(unsigned long))) {
+ vaddr = sgx_get_page(encl_page->epc_page);
+ ret = __edbgrd((void *)((unsigned long)vaddr + offset),
+ (unsigned long *)data);
+ sgx_put_page(vaddr);
+ if (ret) {
+ sgx_dbg(encl, "EDBGRD returned %d\n", ret);
+ return -EFAULT;
+ }
+ }
+
+ memcpy(data + align, buf + i, cnt);
+ vaddr = sgx_get_page(encl_page->epc_page);
+ ret = __edbgwr((void *)((unsigned long)vaddr + offset),
+ (unsigned long *)data);
+ sgx_put_page(vaddr);
+ if (ret) {
+ sgx_dbg(encl, "EDBGWR returned %d\n", ret);
+ return -EFAULT;
+ }
+ } else {
+ if (encl_page->flags & SGX_ENCL_PAGE_TCS &&
+ (offset + (len - i)) > 72)
+ return -ECANCELED;
+
+ vaddr = sgx_get_page(encl_page->epc_page);
+ ret = __edbgrd((void *)((unsigned long)vaddr + offset),
+ (unsigned long *)data);
+ sgx_put_page(vaddr);
+ if (ret) {
+ sgx_dbg(encl, "EDBGRD returned %d\n", ret);
+ return -EFAULT;
+ }
+
+ memcpy(buf + i, data + align, cnt);
+ }
+
+ return cnt;
+}
+
+static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write)
+{
+ struct sgx_encl *encl = vma->vm_private_data;
+ struct sgx_encl_page *entry = NULL;
+ const char *op_str = write ? "EDBGWR" : "EDBGRD";
+ int ret = 0;
+ int i;
+
+ /* If process was forked, VMA is still there but vm_private_data is set
+ * to NULL.
+ */
+ if (!encl)
+ return -EFAULT;
+
+ if (!(encl->flags & SGX_ENCL_DEBUG) ||
+ !(encl->flags & SGX_ENCL_INITIALIZED) ||
+ (encl->flags & SGX_ENCL_DEAD))
+ return -EFAULT;
+
+ sgx_dbg(encl, "%s addr=0x%lx, len=%d\n", op_str, addr, len);
+
+ for (i = 0; i < len; i += ret) {
+ if (!entry || !((addr + i) & (PAGE_SIZE - 1))) {
+ if (entry)
+ entry->flags &= ~SGX_ENCL_PAGE_RESERVED;
+
+ entry = sgx_fault_page(vma, (addr + i) & PAGE_MASK,
+ SGX_FAULT_RESERVE);
+ if (IS_ERR(entry)) {
+ ret = PTR_ERR(entry);
+ entry = NULL;
+ break;
+ }
+ }
+
+ /* No locks are needed because used fields are immutable after
+ * initialization.
+ */
+ ret = sgx_vma_access_word(encl, addr, buf, len, write,
+ entry, i);
+ if (ret < 0)
+ break;
+ }
+
+ if (entry)
+ entry->flags &= ~SGX_ENCL_PAGE_RESERVED;
+
+ return (ret < 0 && ret != -ECANCELED) ? ret : i;
+}
+
const struct vm_operations_struct sgx_vm_ops = {
.close = sgx_vma_close,
.open = sgx_vma_open,
.fault = sgx_vma_fault,
+ .access = sgx_vma_access,
};
--
2.14.1