s3:vfs_crossrename: avoid locking panic in copy_reg()

Use low level backend functions that don't go through the FSA layer.
Done via calling transfer_file() as it was in version before 5c18f07

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15724

Signed-off-by: Pavel Filipenský <pfilipensky@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
(cherry picked from commit 0a5da82f75a43838be3419cab10a50750fa500d7)

diff --git a/source3/modules/vfs_crossrename.c b/source3/modules/vfs_crossrename.c
index 042144bfc4df9264a0f968fd9ca1a5c413316bf6..7c0ae94d257f9dc31cfe0d50ce60be9282b62122 100644 (file)
--- a/source3/modules/vfs_crossrename.c
+++ b/source3/modules/vfs_crossrename.c
@@ -54,10 +54,12 @@ static NTSTATUS copy_reg(vfs_handle_struct *handle,
                         struct files_struct *dstfsp,
                         const struct smb_filename *dest)
 {
-       NTSTATUS status;
-       struct smb_filename *full_fname_src = NULL;
-       struct smb_filename *full_fname_dst = NULL;
+       NTSTATUS status = NT_STATUS_OK;
        int ret;
+       off_t off;
+       int ifd = -1;
+       int ofd = -1;
+       struct timespec ts[2];
 
        if (!VALID_STAT(source->st)) {
                status = NT_STATUS_OBJECT_PATH_NOT_FOUND;
@@ -79,21 +81,6 @@ static NTSTATUS copy_reg(vfs_handle_struct *handle,
                goto out;
        }
 
-       full_fname_src = full_path_from_dirfsp_atname(talloc_tos(),
-                                                     srcfsp,
-                                                     source);
-       if (full_fname_src == NULL) {
-               status = NT_STATUS_NO_MEMORY;
-               goto out;
-       }
-       full_fname_dst = full_path_from_dirfsp_atname(talloc_tos(),
-                                                     dstfsp,
-                                                     dest);
-       if (full_fname_dst == NULL) {
-               status = NT_STATUS_NO_MEMORY;
-               goto out;
-       }
-
        ret = SMB_VFS_NEXT_UNLINKAT(handle,
                                    dstfsp,
                                    dest,
@@ -103,40 +90,96 @@ static NTSTATUS copy_reg(vfs_handle_struct *handle,
                goto out;
        }
 
+       ifd = openat(fsp_get_pathref_fd(srcfsp),
+                    source->base_name,
+                    O_RDONLY,
+                    0);
+       if (ifd < 0) {
+               status = map_nt_error_from_unix(errno);
+               goto out;
+       }
+
+       ofd = openat(fsp_get_pathref_fd(dstfsp),
+                    dest->base_name,
+                    O_WRONLY | O_CREAT | O_TRUNC | O_NOFOLLOW,
+                    0600);
+       if (ofd < 0) {
+               status = map_nt_error_from_unix(errno);
+               goto out;
+       }
+
+       off = transfer_file(ifd, ofd, source->st.st_ex_size);
+       if (off == -1) {
+               status = map_nt_error_from_unix(errno);
+               goto out;
+       }
+
+       ret = fchown(ofd, source->st.st_ex_uid, source->st.st_ex_gid);
+       if (ret == -1 && errno != EPERM) {
+               status = map_nt_error_from_unix(errno);
+               goto out;
+       }
+
        /*
-        * copy_internals() takes attribute values from the NTrename call.
-        *
-        * From MS-CIFS:
-        *
-        * "If the attribute is 0x0000, then only normal files are renamed.
-        * If the system file or hidden attributes are specified, then the
-        * rename is inclusive of both special types."
+        * fchown turns off set[ug]id bits for non-root,
+        * so do the chmod last.
         */
-       status = copy_internals(talloc_tos(),
-                               handle->conn,
-                               NULL,
-                               srcfsp, /* src_dirfsp */
-                               full_fname_src,
-                               dstfsp, /* dst_dirfsp */
-                               full_fname_dst,
-                               FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_SYSTEM);
-       if (!NT_STATUS_IS_OK(status)) {
+       ret = fchmod(ofd, source->st.st_ex_mode & 07777);
+       if (ret == -1 && errno != EPERM) {
+               status = map_nt_error_from_unix(errno);
                goto out;
        }
 
-       ret = SMB_VFS_NEXT_UNLINKAT(handle,
-                                   srcfsp,
-                                   source,
-                                   0);
+       /* Try to copy the old file's modtime and access time.  */
+       ts[0] = source->st.st_ex_atime;
+       ts[1] = source->st.st_ex_mtime;
+       ret = futimens(ofd, ts);
+       if (ret == -1) {
+               DBG_DEBUG("Updating the time stamp on destinaton '%s' failed "
+                         "with '%s'. Rename operation can continue.\n",
+                         dest->base_name,
+                         strerror(errno));
+       }
+
+       ret = close(ifd);
+       if (ret == -1) {
+               status = map_nt_error_from_unix(errno);
+               goto out;
+       }
+       ifd = -1;
+
+       ret = close(ofd);
        if (ret == -1) {
                status = map_nt_error_from_unix(errno);
                goto out;
        }
+       ofd = -1;
+
+       ret = SMB_VFS_NEXT_UNLINKAT(handle, srcfsp, source, 0);
+       if (ret == -1) {
+               status = map_nt_error_from_unix(errno);
+       }
 
-  out:
+out:
+       if (ifd != -1) {
+               ret = close(ifd);
+               if (ret == -1) {
+                       DBG_DEBUG("Failed to close %s (%d): %s.\n",
+                                 source->base_name,
+                                 ifd,
+                                 strerror(errno));
+               }
+       }
+       if (ofd != -1) {
+               ret = close(ofd);
+               if (ret == -1) {
+                       DBG_DEBUG("Failed to close %s (%d): %s.\n",
+                                 dest->base_name,
+                                 ofd,
+                                 strerror(errno));
+               }
+       }
 
-       TALLOC_FREE(full_fname_src);
-       TALLOC_FREE(full_fname_dst);
        return status;
 }