+/* At the start of each type of access control entry. */
+typedef struct {
+ /* enum ace_type, specifies what type of ACE this is. */
+ u8 type;
+
+ /* bitwise OR of the inherit ACE flags #defined above */
+ u8 flags;
+
+ /* Size of the access control entry. */
+ u8 size;
+} ACEHeader;
+
+/* Grants rights to a user or group */
+typedef struct {
+ ACEHeader hdr;
+ u32 mask;
+ u32 sid_start;
+} AccessAllowedACE;
+
+/* Denies rights to a user or group */
+typedef struct {
+ ACEHeader hdr;
+ u32 mask;
+ u32 sid_start;
+} AccessDeniedACE;
+
+typedef struct {
+ ACEHeader hdr;
+ u32 mask;
+ u32 sid_start;
+} SystemAuditACE;
+
+
+/* Header of an access control list. */
+typedef struct {
+ /* ACL_REVISION or ACL_REVISION_DS */
+ u8 revision;
+
+ /* padding */
+ u8 sbz1;
+
+ /* Total size of the ACL, including all access control entries */
+ u16 acl_size;
+
+ /* Number of access control entry structures that follow the ACL
+ * structure. */
+ u16 ace_count;
+
+ /* padding */
+ u16 sbz2;
+} ACL;
+
+/* A structure used to identify users or groups. */
+typedef struct {
+
+ /* example: 0x1 */
+ u8 revision;
+ u8 sub_authority_count;
+
+ /* Identifies the authority that issued the SID. Can be, but does not
+ * have to be, one of enum sid_authority_value */
+ u8 identifier_authority[6];
+
+ u32 sub_authority[0];
+} SID;
+
+
+typedef struct {
+ /* Example: 0x1 */
+ u8 revision;
+ /* Example: 0x0 */
+ u8 sbz1;
+ /* Example: 0x4149 */
+ u16 security_descriptor_control;
+
+ /* Offset of a SID structure in the security descriptor. */
+ /* Example: 0x14 */
+ u32 owner_offset;
+
+ /* Offset of a SID structure in the security descriptor. */
+ /* Example: 0x24 */
+ u32 group_offset;
+
+ /* Offset of an ACL structure in the security descriptor. */
+ /* System ACL. */
+ /* Example: 0x00 */
+ u32 sacl_offset;
+
+ /* Offset of an ACL structure in the security descriptor. */
+ /* Discretionary ACL. */
+ /* Example: 0x34 */
+ u32 dacl_offset;
+} SecurityDescriptor;
+
+/*
+ * This is a hack to work around a problem in libntfs-3g. libntfs-3g validates
+ * security descriptors with a function named ntfs_valid_descr().
+ * ntfs_valid_descr() considers a security descriptor that ends in a SACL
+ * (Sysetm Access Control List) with no ACE's (Access Control Entries) to be
+ * invalid. However, a security descriptor like this exists in the Windows 7
+ * install.wim. Here, security descriptors matching this pattern are modified
+ * to have no SACL. This should make no difference since the SACL had no
+ * entries anyway; however this ensures that that the security descriptors pass
+ * the validation in libntfs-3g.
+ */
+static void
+empty_sacl_fixup(u8 *descr, u64 *size_p)
+{
+ /* No-op if no NTFS-3g support, or if NTFS-3g is version 2013 or later
+ * */
+#if defined(WITH_NTFS_3G) && !defined(HAVE_NTFS_MNT_RDONLY)
+ if (*size_p >= sizeof(SecurityDescriptor)) {
+ SecurityDescriptor *sd = (SecurityDescriptor*)descr;
+ u32 sacl_offset = le32_to_cpu(sd->sacl_offset);
+ if (sacl_offset == *size_p - sizeof(ACL)) {
+ sd->sacl_offset = cpu_to_le32(0);
+ *size_p -= sizeof(ACL);
+ }
+ }
+#endif
+}
+
+/*