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[V2,13/32] x86/sgx: Create utility to validate user provided offset and length

Message ID e2374b14ab79596926d0de57e6b6952304e40070.1644274683.git.reinette.chatre@intel.com (mailing list archive)
State New, archived
Headers show
Series x86/sgx and selftests/sgx: Support SGX2 | expand

Commit Message

Reinette Chatre Feb. 8, 2022, 12:45 a.m. UTC
User provided offset and length is validated when parsing the parameters
of the SGX_IOC_ENCLAVE_ADD_PAGES ioctl(). Extract this validation
into a utility that can be used by the SGX2 ioctl()s that will
also provide these values.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
---
Changes since V1:
- New patch

 arch/x86/kernel/cpu/sgx/ioctl.c | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 7e0819a89532..6e7cc441156b 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -378,6 +378,26 @@  static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
 	return ret;
 }
 
+/*
+ * Ensure user provided offset and length values are valid for
+ * an enclave.
+ */
+static int sgx_validate_offset_length(struct sgx_encl *encl,
+				      unsigned long offset,
+				      unsigned long length)
+{
+	if (!IS_ALIGNED(offset, PAGE_SIZE))
+		return -EINVAL;
+
+	if (!length || length & (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	if (offset + length - PAGE_SIZE >= encl->size)
+		return -EINVAL;
+
+	return 0;
+}
+
 /**
  * sgx_ioc_enclave_add_pages() - The handler for %SGX_IOC_ENCLAVE_ADD_PAGES
  * @encl:       an enclave pointer
@@ -431,14 +451,10 @@  static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
 	if (copy_from_user(&add_arg, arg, sizeof(add_arg)))
 		return -EFAULT;
 
-	if (!IS_ALIGNED(add_arg.offset, PAGE_SIZE) ||
-	    !IS_ALIGNED(add_arg.src, PAGE_SIZE))
-		return -EINVAL;
-
-	if (!add_arg.length || add_arg.length & (PAGE_SIZE - 1))
+	if (!IS_ALIGNED(add_arg.src, PAGE_SIZE))
 		return -EINVAL;
 
-	if (add_arg.offset + add_arg.length - PAGE_SIZE >= encl->size)
+	if (sgx_validate_offset_length(encl, add_arg.offset, add_arg.length))
 		return -EINVAL;
 
 	if (copy_from_user(&secinfo, (void __user *)add_arg.secinfo,