vfs_acl_common: Windows style default ACL

Reintroduce Windows style default ACL, but this time as an optional
feature, not changing default behaviour.

Original bugreport that got reverted because it changed the default
behaviour: https://bugzilla.samba.org/show_bug.cgi?id=12028

Bug: https://bugzilla.samba.org/show_bug.cgi?id=12177

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
(cherry picked from commit 0730cb7e1ce33dbc5fc48a7363204c1220400c68)

1 files changed, 76 insertions, 0 deletions

diff --git a/source3/modules/vfs_acl_common.c b/source3/modules/vfs_acl_common.c
index e8eaa4fcd2c..44fef12a377 100644
--- a/source3/modules/vfs_acl_common.c
+++ b/source3/modules/vfs_acl_common.c
@@ -507,6 +507,78 @@ static NTSTATUS make_default_acl_posix(TALLOC_CTX *ctx,
 	return NT_STATUS_OK;
 }
 
+static NTSTATUS make_default_acl_windows(TALLOC_CTX *ctx,
+					 const char *name,
+					 SMB_STRUCT_STAT *psbuf,
+					 struct security_descriptor **ppdesc)
+{
+	struct dom_sid owner_sid, group_sid;
+	size_t size = 0;
+	struct security_ace aces[4];
+	uint32_t access_mask = 0;
+	mode_t mode = psbuf->st_ex_mode;
+	struct security_acl *new_dacl = NULL;
+	int idx = 0;
+
+	DBG_DEBUG("file [%s] mode [0%o]\n", name, (int)mode);
+
+	uid_to_sid(&owner_sid, psbuf->st_ex_uid);
+	gid_to_sid(&group_sid, psbuf->st_ex_gid);
+
+	/*
+	 * We provide 2 ACEs:
+	 * - Owner
+	 * - NT System
+	 */
+
+	if (mode & S_IRUSR) {
+		if (mode & S_IWUSR) {
+			access_mask |= SEC_RIGHTS_FILE_ALL;
+		} else {
+			access_mask |= SEC_RIGHTS_FILE_READ | SEC_FILE_EXECUTE;
+		}
+	}
+	if (mode & S_IWUSR) {
+		access_mask |= SEC_RIGHTS_FILE_WRITE | SEC_STD_DELETE;
+	}
+
+	init_sec_ace(&aces[idx],
+		     &owner_sid,
+		     SEC_ACE_TYPE_ACCESS_ALLOWED,
+		     access_mask,
+		     0);
+	idx++;
+
+	init_sec_ace(&aces[idx],
+		     &global_sid_System,
+		     SEC_ACE_TYPE_ACCESS_ALLOWED,
+		     SEC_RIGHTS_FILE_ALL,
+		     0);
+	idx++;
+
+	new_dacl = make_sec_acl(ctx,
+				NT4_ACL_REVISION,
+				idx,
+				aces);
+
+	if (!new_dacl) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	*ppdesc = make_sec_desc(ctx,
+				SECURITY_DESCRIPTOR_REVISION_1,
+				SEC_DESC_SELF_RELATIVE|SEC_DESC_DACL_PRESENT,
+				&owner_sid,
+				&group_sid,
+				NULL,
+				new_dacl,
+				&size);
+	if (!*ppdesc) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	return NT_STATUS_OK;
+}
+
 static NTSTATUS make_default_filesystem_acl(TALLOC_CTX *ctx,
 					    struct acl_common_config *config,
 					    const char *name,
@@ -521,6 +593,10 @@ static NTSTATUS make_default_filesystem_acl(TALLOC_CTX *ctx,
 		status =  make_default_acl_posix(ctx, name, psbuf, ppdesc);
 		break;
 
+	case DEFAULT_ACL_WINDOWS:
+		status =  make_default_acl_windows(ctx, name, psbuf, ppdesc);
+		break;
+
 	default:
 		DBG_ERR("unknown acl style %d", config->default_acl_style);
 		status = NT_STATUS_INTERNAL_ERROR;