From: Volker Lendecke <vl@samba.org>
Date: Tue, 14 Jun 2022 14:33:57 +0000 (+0200)
Subject: VFS: NULL dirfsp for openat on stream opens
X-Git-Tag: tevent-0.13.0~17
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c267c9839eb75ee458e28d545e8941aec35b8062;p=thirdparty%2Fsamba.git

VFS: NULL dirfsp for openat on stream opens

The main optimization is to avoid non_widelink_open() for streams
opens based on the fact that all streams opens are relative to
fsp->base_fsp, which is a pathref fsp already.

Neither streams_xattr nor streams_depot referenced dirfsp for the
streams case. Make this more obvious in the callers by passing NULL
and asserting this: non-streams opens and streams opens are just
different things, streams-opens can and do reference a base fsp and
don't need the non_widelink_open logic.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
---

diff --git a/source3/modules/vfs_fruit.c b/source3/modules/vfs_fruit.c
index 05ab8fcea69..685c15bcaa7 100644
--- a/source3/modules/vfs_fruit.c
+++ b/source3/modules/vfs_fruit.c
@@ -2666,7 +2666,7 @@ static ssize_t fruit_pwrite_meta_stream(vfs_handle_struct *handle,
 		}
 
 		fd = SMB_VFS_NEXT_OPENAT(handle,
-					 fsp->conn->cwd_fsp,
+					 NULL, /* opening a stream */
 					 fsp->fsp_name,
 					 fsp,
 					 fio->flags,
diff --git a/source3/modules/vfs_streams_depot.c b/source3/modules/vfs_streams_depot.c
index 107543f6bbc..6722d712bff 100644
--- a/source3/modules/vfs_streams_depot.c
+++ b/source3/modules/vfs_streams_depot.c
@@ -684,6 +684,7 @@ static int streams_depot_openat(struct vfs_handle_struct *handle,
 	}
 
 	SMB_ASSERT(fsp_is_alternate_stream(fsp));
+	SMB_ASSERT(dirfsp == NULL);
 	SMB_ASSERT(VALID_STAT(fsp->base_fsp->fsp_name->st));
 
 	create_it = (mode & O_CREAT);
diff --git a/source3/modules/vfs_streams_xattr.c b/source3/modules/vfs_streams_xattr.c
index 3e39770bb37..dd689261449 100644
--- a/source3/modules/vfs_streams_xattr.c
+++ b/source3/modules/vfs_streams_xattr.c
@@ -344,6 +344,7 @@ static int streams_xattr_openat(struct vfs_handle_struct *handle,
 	}
 
 	SMB_ASSERT(fsp_is_alternate_stream(fsp));
+	SMB_ASSERT(dirfsp == NULL);
 
 	status = streams_xattr_get_name(handle, talloc_tos(),
 					smb_fname->stream_name, &xattr_name);
diff --git a/source3/smbd/files.c b/source3/smbd/files.c
index c9660555569..d6ce87cc5fb 100644
--- a/source3/smbd/files.c
+++ b/source3/smbd/files.c
@@ -667,7 +667,7 @@ NTSTATUS open_stream_pathref_fsp(
 
 	fd = SMB_VFS_OPENAT(
 		conn,
-		dirfsp,
+		NULL,	/* stream open is relative to fsp->base_fsp */
 		smb_fname,
 		fsp,
 		O_RDONLY|O_NONBLOCK|O_NOFOLLOW,
diff --git a/source3/smbd/open.c b/source3/smbd/open.c
index 8cb349d78b0..ce9b43fa072 100644
--- a/source3/smbd/open.c
+++ b/source3/smbd/open.c
@@ -937,6 +937,35 @@ NTSTATUS fd_openat(const struct files_struct *dirfsp,
 		flags |= O_NOFOLLOW;
 	}
 
+	if (fsp_is_alternate_stream(fsp)) {
+		int fd;
+
+		SMB_ASSERT(is_named_stream(smb_fname));
+
+		fd = SMB_VFS_OPENAT(
+			conn,
+			NULL,	/* stream open is relative to fsp->base_fsp */
+			smb_fname,
+			fsp,
+			flags,
+			mode);
+		if (fd == -1) {
+			status = map_nt_error_from_unix(errno);
+		}
+		fsp_set_fd(fsp, fd);
+
+		if (fd != -1) {
+			status = vfs_stat_fsp(fsp);
+			if (!NT_STATUS_IS_OK(status)) {
+				DBG_DEBUG("vfs_stat_fsp failed: %s\n",
+					  nt_errstr(status));
+				fd_close(fsp);
+			}
+		}
+
+		return status;
+	}
+
 	/*
 	 * Only follow symlinks within a share
 	 * definition.
diff --git a/source3/torture/cmd_vfs.c b/source3/torture/cmd_vfs.c
index b27eca87ab4..dab458de69e 100644
--- a/source3/torture/cmd_vfs.c
+++ b/source3/torture/cmd_vfs.c
@@ -418,6 +418,8 @@ static NTSTATUS cmd_open(struct vfs_state *vfs, TALLOC_CTX *mem_ctx, int argc, c
 			goto fail;
 		}
 
+		TALLOC_FREE(fspcwd);
+
 		fsp->base_fsp = base_name->fsp;
 	}