[PATCH for v24 2/3] x86/sgx: Destroy enclave if EADD fails

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

__sgx_encl_add_page() can only fail in the case of EPCM conflict at least
in non-artificial situations. Also, it consistent semantics in rollback is
something to pursue for. Thus, destroy enclave when the EADD fails as we do
when EEXTEND fails already.

In the cases it is sane to return -EIO. From this the caller can deduce
the failure and knows that the enclave was destroyed. The previous
-EFAULT could happen in numerous situations.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/ioctl.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index d53aee5a64c1..289af607f634 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -338,7 +338,7 @@ static int __sgx_encl_add_page(struct sgx_encl *encl,
 	kunmap_atomic((void *)pginfo.contents);
 	put_page(src_page);
 
-	return ret ? -EFAULT : 0;
+	return ret ? -EIO : 0;
 }
 
 static int __sgx_encl_extend(struct sgx_encl *encl,
@@ -353,7 +353,7 @@ static int __sgx_encl_extend(struct sgx_encl *encl,
 		if (ret) {
 			if (encls_failed(ret))
 				ENCLS_WARN(ret, "EEXTEND");
-			return -EFAULT;
+			return -EIO;
 		}
 	}
 
@@ -413,8 +413,10 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
 
 	ret = __sgx_encl_add_page(encl, encl_page, epc_page, secinfo,
 				  addp->src);
-	if (ret)
+	if (ret) {
+		sgx_encl_destroy(encl);
 		goto err_out;
+	}
 
 	/*
 	 * Complete the "add" before doing the "extend" so that the "add"
@@ -498,10 +500,9 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
  *
  * Return:
  *   0 on success,
- *   -EINVAL if any input param or the SECINFO contains invalid data,
  *   -EACCES if an executable source page is located in a noexec partition,
- *   -ENOMEM if any memory allocation, including EPC, fails,
- *   -ERESTARTSYS if a pending signal is recognized
+ *   -EIO if either ENCLS[EADD] or ENCLS[EEXTEND] fails
+ *   -errno otherwise
  */
 static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
 {
-- 
2.20.1