smbd: Add mem_ctx to {f,}get_nt_acl VFS call

This makes it clear which context the returned SD is allocated on, as
a number of callers do not want it on talloc_tos().

As the ACL transformation allocates and then no longer needs a great
deal of memory, a talloc_stackframe() call is used to contain the
memory that is not returned further up the stack.

Andrew Bartlett

6 files changed, 65 insertions, 37 deletions

diff --git a/source3/smbd/file_access.c b/source3/smbd/file_access.c
index 015679deb0..0e74207b84 100644
--- a/source3/smbd/file_access.c
+++ b/source3/smbd/file_access.c
@@ -151,11 +151,11 @@ bool can_write_to_file(connection_struct *conn,
 
 bool directory_has_default_acl(connection_struct *conn, const char *fname)
 {
-	/* returns talloced off tos. */
 	struct security_descriptor *secdesc = NULL;
 	unsigned int i;
 	NTSTATUS status = SMB_VFS_GET_NT_ACL(conn, fname,
-				SECINFO_DACL, &secdesc);
+					     SECINFO_DACL, talloc_tos(),
+					     &secdesc);
 
 	if (!NT_STATUS_IS_OK(status) ||
 			secdesc == NULL ||
diff --git a/source3/smbd/nttrans.c b/source3/smbd/nttrans.c
index 6848d10397..1011bd7025 100644
--- a/source3/smbd/nttrans.c
+++ b/source3/smbd/nttrans.c
@@ -1907,6 +1907,7 @@ NTSTATUS smbd_do_query_security_desc(connection_struct *conn,
 {
 	NTSTATUS status;
 	struct security_descriptor *psd = NULL;
+	TALLOC_CTX *frame = talloc_stackframe();
 
 	/*
 	 * Get the permissions to return.
@@ -1932,13 +1933,13 @@ NTSTATUS smbd_do_query_security_desc(connection_struct *conn,
 	}
 
 	if (!lp_nt_acl_support(SNUM(conn))) {
-		status = get_null_nt_acl(mem_ctx, &psd);
+		status = get_null_nt_acl(frame, &psd);
 	} else if (security_info_wanted & SECINFO_LABEL) {
 		/* Like W2K3 return a null object. */
-		status = get_null_nt_acl(mem_ctx, &psd);
+		status = get_null_nt_acl(frame, &psd);
 	} else {
 		status = SMB_VFS_FGET_NT_ACL(
-			fsp, security_info_wanted, &psd);
+			fsp, security_info_wanted, frame, &psd);
 	}
 	if (!NT_STATUS_IS_OK(status)) {
 		return status;
@@ -1989,7 +1990,7 @@ NTSTATUS smbd_do_query_security_desc(connection_struct *conn,
 	}
 
 	if (max_data_count < *psd_size) {
-		TALLOC_FREE(psd);
+		TALLOC_FREE(frame);
 		return NT_STATUS_BUFFER_TOO_SMALL;
 	}
 
@@ -1997,11 +1998,11 @@ NTSTATUS smbd_do_query_security_desc(connection_struct *conn,
 				   ppmarshalled_sd, psd_size);
 
 	if (!NT_STATUS_IS_OK(status)) {
-		TALLOC_FREE(psd);
+		TALLOC_FREE(frame);
 		return status;
 	}
 
-	TALLOC_FREE(psd);
+	TALLOC_FREE(frame);
 	return NT_STATUS_OK;
 }
 
diff --git a/source3/smbd/open.c b/source3/smbd/open.c
index d4babd40f7..efabe4a480 100644
--- a/source3/smbd/open.c
+++ b/source3/smbd/open.c
@@ -115,7 +115,7 @@ NTSTATUS smbd_check_access_rights(struct connection_struct *conn,
 	status = SMB_VFS_GET_NT_ACL(conn, smb_fname->base_name,
 			(SECINFO_OWNER |
 			SECINFO_GROUP |
-			SECINFO_DACL),&sd);
+			 SECINFO_DACL), talloc_tos(), &sd);
 
 	if (!NT_STATUS_IS_OK(status)) {
 		DEBUG(10, ("smbd_check_access_rights: Could not get acl "
@@ -237,6 +237,7 @@ static NTSTATUS check_parent_access(struct connection_struct *conn,
 	status = SMB_VFS_GET_NT_ACL(conn,
 				parent_dir,
 				SECINFO_DACL,
+				    talloc_tos(),
 				&parent_sd);
 
 	if (!NT_STATUS_IS_OK(status)) {
@@ -1683,7 +1684,8 @@ static NTSTATUS smbd_calculate_maximum_allowed_access(
 	status = SMB_VFS_GET_NT_ACL(conn, smb_fname->base_name,
 				    (SECINFO_OWNER |
 				     SECINFO_GROUP |
-				     SECINFO_DACL),&sd);
+				     SECINFO_DACL),
+				    talloc_tos(), &sd);
 
 	if (NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
 		/*
@@ -3425,7 +3427,7 @@ NTSTATUS open_streams_for_delete(connection_struct *conn,
 
 static NTSTATUS inherit_new_acl(files_struct *fsp)
 {
-	TALLOC_CTX *ctx = talloc_tos();
+	TALLOC_CTX *frame = talloc_stackframe();
 	char *parent_name = NULL;
 	struct security_descriptor *parent_desc = NULL;
 	NTSTATUS status = NT_STATUS_OK;
@@ -3437,14 +3439,15 @@ static NTSTATUS inherit_new_acl(files_struct *fsp)
 	bool inheritable_components = false;
 	size_t size = 0;
 
-	if (!parent_dirname(ctx, fsp->fsp_name->base_name, &parent_name, NULL)) {
+	if (!parent_dirname(frame, fsp->fsp_name->base_name, &parent_name, NULL)) {
 		return NT_STATUS_NO_MEMORY;
 	}
 
 	status = SMB_VFS_GET_NT_ACL(fsp->conn,
-				parent_name,
-				(SECINFO_OWNER | SECINFO_GROUP | SECINFO_DACL),
-				&parent_desc);
+				    parent_name,
+				    (SECINFO_OWNER | SECINFO_GROUP | SECINFO_DACL),
+				    frame,
+				    &parent_desc);
 	if (!NT_STATUS_IS_OK(status)) {
 		return status;
 	}
@@ -3453,6 +3456,7 @@ static NTSTATUS inherit_new_acl(files_struct *fsp)
 					fsp->is_directory);
 
 	if (!inheritable_components && !inherit_owner) {
+		TALLOC_FREE(frame);
 		/* Nothing to inherit and not setting owner. */
 		return NT_STATUS_OK;
 	}
@@ -3478,7 +3482,7 @@ static NTSTATUS inherit_new_acl(files_struct *fsp)
 		group_sid = &fsp->conn->session_info->security_token->sids[PRIMARY_GROUP_SID_INDEX];
 	}
 
-	status = se_create_child_secdesc(ctx,
+	status = se_create_child_secdesc(frame,
 			&psd,
 			&size,
 			parent_desc,
@@ -3486,6 +3490,7 @@ static NTSTATUS inherit_new_acl(files_struct *fsp)
 			group_sid,
 			fsp->is_directory);
 	if (!NT_STATUS_IS_OK(status)) {
+		TALLOC_FREE(frame);
 		return status;
 	}
 
@@ -3516,6 +3521,7 @@ static NTSTATUS inherit_new_acl(files_struct *fsp)
 	if (inherit_owner) {
 		unbecome_root();
 	}
+	TALLOC_FREE(frame);
 	return status;
 }
 
diff --git a/source3/smbd/posix_acls.c b/source3/smbd/posix_acls.c
index c535502efe..05cd2a740d 100644
--- a/source3/smbd/posix_acls.c
+++ b/source3/smbd/posix_acls.c
@@ -3389,6 +3389,7 @@ static NTSTATUS posix_get_nt_acl_common(struct connection_struct *conn,
 				      SMB_ACL_T posix_acl,
 				      SMB_ACL_T def_acl,
 				      uint32_t security_info,
+				      TALLOC_CTX *mem_ctx,
 				      struct security_descriptor **ppdesc)
 {
 	struct dom_sid owner_sid;
@@ -3601,7 +3602,7 @@ static NTSTATUS posix_get_nt_acl_common(struct connection_struct *conn,
 		}
 	} /* security_info & SECINFO_DACL */
 
-	psd = make_standard_sec_desc( talloc_tos(),
+	psd = make_standard_sec_desc(mem_ctx,
 			(security_info & SECINFO_OWNER) ? &owner_sid : NULL,
 			(security_info & SECINFO_GROUP) ? &group_sid : NULL,
 			psa,
@@ -3652,11 +3653,14 @@ static NTSTATUS posix_get_nt_acl_common(struct connection_struct *conn,
 }
 
 NTSTATUS posix_fget_nt_acl(struct files_struct *fsp, uint32_t security_info,
+			   TALLOC_CTX *mem_ctx,
 			   struct security_descriptor **ppdesc)
 {
 	SMB_STRUCT_STAT sbuf;
 	SMB_ACL_T posix_acl = NULL;
 	struct pai_val *pal;
+	TALLOC_CTX *frame = talloc_stackframe();
+	NTSTATUS status;
 
 	*ppdesc = NULL;
 
@@ -3665,33 +3669,42 @@ NTSTATUS posix_fget_nt_acl(struct files_struct *fsp, uint32_t security_info,
 
 	/* can it happen that fsp_name == NULL ? */
 	if (fsp->is_directory ||  fsp->fh->fd == -1) {
-		return posix_get_nt_acl(fsp->conn, fsp->fsp_name->base_name,
-					security_info, ppdesc);
+		status = posix_get_nt_acl(fsp->conn, fsp->fsp_name->base_name,
+					  security_info, mem_ctx, ppdesc);
+		TALLOC_FREE(frame);
+		return status;
 	}
 
 	/* Get the stat struct for the owner info. */
 	if(SMB_VFS_FSTAT(fsp, &sbuf) != 0) {
+		TALLOC_FREE(frame);
 		return map_nt_error_from_unix(errno);
 	}
 
 	/* Get the ACL from the fd. */
-	posix_acl = SMB_VFS_SYS_ACL_GET_FD(fsp, talloc_tos());
+	posix_acl = SMB_VFS_SYS_ACL_GET_FD(fsp, frame);
 
 	pal = fload_inherited_info(fsp);
 
-	return posix_get_nt_acl_common(fsp->conn, fsp->fsp_name->base_name,
-				       &sbuf, pal, posix_acl, NULL,
-				       security_info, ppdesc);
+	status = posix_get_nt_acl_common(fsp->conn, fsp->fsp_name->base_name,
+					 &sbuf, pal, posix_acl, NULL,
+					 security_info, mem_ctx, ppdesc);
+	TALLOC_FREE(frame);
+	return status;
 }
 
 NTSTATUS posix_get_nt_acl(struct connection_struct *conn, const char *name,
-			  uint32_t security_info, struct security_descriptor **ppdesc)
+			  uint32_t security_info,
+			  TALLOC_CTX *mem_ctx,
+			  struct security_descriptor **ppdesc)
 {
 	SMB_ACL_T posix_acl = NULL;
 	SMB_ACL_T def_acl = NULL;
 	struct pai_val *pal;
 	struct smb_filename smb_fname;
 	int ret;
+	TALLOC_CTX *frame = talloc_stackframe();
+	NTSTATUS status;
 
 	*ppdesc = NULL;
 
@@ -3708,26 +3721,29 @@ NTSTATUS posix_get_nt_acl(struct connection_struct *conn, const char *name,
 	}
 
 	if (ret == -1) {
+		TALLOC_FREE(frame);
 		return map_nt_error_from_unix(errno);
 	}
 
 	/* Get the ACL from the path. */
 	posix_acl = SMB_VFS_SYS_ACL_GET_FILE(conn, name,
-					     SMB_ACL_TYPE_ACCESS, talloc_tos());
+					     SMB_ACL_TYPE_ACCESS, frame);
 
 	/* If it's a directory get the default POSIX ACL. */
 	if(S_ISDIR(smb_fname.st.st_ex_mode)) {
 		def_acl = SMB_VFS_SYS_ACL_GET_FILE(conn, name,
-                                                   SMB_ACL_TYPE_DEFAULT,
-                                                   talloc_tos());
+						   SMB_ACL_TYPE_DEFAULT, frame);
 		def_acl = free_empty_sys_acl(conn, def_acl);
 	}
 
 	pal = load_inherited_info(conn, name);
 
-	return posix_get_nt_acl_common(conn, name, &smb_fname.st, pal,
-				       posix_acl, def_acl, security_info,
-				       ppdesc);
+	status = posix_get_nt_acl_common(conn, name, &smb_fname.st, pal,
+					 posix_acl, def_acl, security_info,
+					 mem_ctx,
+					 ppdesc);
+	TALLOC_FREE(frame);
+	return status;
 }
 
 /****************************************************************************
@@ -4953,7 +4969,7 @@ bool set_unix_posix_acl(connection_struct *conn, files_struct *fsp, const char *
 
 struct security_descriptor *get_nt_acl_no_snum( TALLOC_CTX *ctx, const char *fname, uint32 security_info_wanted)
 {
-	struct security_descriptor *psd, *ret_sd;
+	struct security_descriptor *ret_sd;
 	connection_struct *conn;
 	files_struct finfo;
 	struct fd_handle fh;
@@ -4999,7 +5015,9 @@ struct security_descriptor *get_nt_acl_no_snum( TALLOC_CTX *ctx, const char *fna
 		return NULL;
 	}
 
-	if (!NT_STATUS_IS_OK(SMB_VFS_FGET_NT_ACL( &finfo, security_info_wanted, &psd))) {
+	if (!NT_STATUS_IS_OK(SMB_VFS_FGET_NT_ACL( &finfo,
+						  security_info_wanted,
+						  ctx, &ret_sd))) {
 		DEBUG(0,("get_nt_acl_no_snum: get_nt_acl returned zero.\n"));
 		TALLOC_FREE(finfo.fsp_name);
 		conn_free(conn);
@@ -5007,8 +5025,6 @@ struct security_descriptor *get_nt_acl_no_snum( TALLOC_CTX *ctx, const char *fna
 		return NULL;
 	}
 
-	ret_sd = dup_sec_desc( ctx, psd );
-
 	TALLOC_FREE(finfo.fsp_name);
 	conn_free(conn);
 	TALLOC_FREE(frame);
diff --git a/source3/smbd/proto.h b/source3/smbd/proto.h
index 143da491e0..1e5883b039 100644
--- a/source3/smbd/proto.h
+++ b/source3/smbd/proto.h
@@ -714,9 +714,12 @@ NTSTATUS unpack_nt_owners(connection_struct *conn, uid_t *puser, gid_t *pgrp, ui
 bool current_user_in_group(connection_struct *conn, gid_t gid);
 SMB_ACL_T free_empty_sys_acl(connection_struct *conn, SMB_ACL_T the_acl);
 NTSTATUS posix_fget_nt_acl(struct files_struct *fsp, uint32_t security_info,
+			   TALLOC_CTX *mem_ctx,
 			   struct security_descriptor **ppdesc);
 NTSTATUS posix_get_nt_acl(struct connection_struct *conn, const char *name,
-			  uint32_t security_info, struct security_descriptor **ppdesc);
+			  uint32_t security_info,
+			  TALLOC_CTX *mem_ctx,
+			  struct security_descriptor **ppdesc);
 NTSTATUS try_chown(files_struct *fsp, uid_t uid, gid_t gid);
 NTSTATUS append_parent_acl(files_struct *fsp,
 				const struct security_descriptor *pcsd,
diff --git a/source3/smbd/vfs.c b/source3/smbd/vfs.c
index 182e334ade..3a95c588c5 100644
--- a/source3/smbd/vfs.c
+++ b/source3/smbd/vfs.c
@@ -2165,20 +2165,22 @@ NTSTATUS smb_vfs_call_fsctl(struct vfs_handle_struct *handle,
 NTSTATUS smb_vfs_call_fget_nt_acl(struct vfs_handle_struct *handle,
 				  struct files_struct *fsp,
 				  uint32 security_info,
+				  TALLOC_CTX *mem_ctx,
 				  struct security_descriptor **ppdesc)
 {
 	VFS_FIND(fget_nt_acl);
 	return handle->fns->fget_nt_acl_fn(handle, fsp, security_info,
-					   ppdesc);
+					   mem_ctx, ppdesc);
 }
 
 NTSTATUS smb_vfs_call_get_nt_acl(struct vfs_handle_struct *handle,
 				 const char *name,
 				 uint32 security_info,
+				 TALLOC_CTX *mem_ctx,
 				 struct security_descriptor **ppdesc)
 {
 	VFS_FIND(get_nt_acl);
-	return handle->fns->get_nt_acl_fn(handle, name, security_info, ppdesc);
+	return handle->fns->get_nt_acl_fn(handle, name, security_info, mem_ctx, ppdesc);
 }
 
 NTSTATUS smb_vfs_call_fset_nt_acl(struct vfs_handle_struct *handle,