Pali Rohár <pali@xxxxxxxxxx> writes:
> If CREATE was successful but SMB2_OP_SET_REPARSE failed then remove the
> intermediate object created by CREATE. Otherwise empty object stay on the
> server when reparse call failed.
>
> This ensures that if the creating of special files is unsupported by the
> server then no empty file stay on the server as a result of unsupported
> operation.
>
> Fixes: 102466f303ff ("smb: client: allow creating special files via reparse points")
> Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> ---
> fs/smb/client/smb2inode.c | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
> index 11a1c53c64e0..af42f44bdcf4 100644
> --- a/fs/smb/client/smb2inode.c
> +++ b/fs/smb/client/smb2inode.c
> @@ -1205,6 +1205,8 @@ struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
> struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
> struct cifsFileInfo *cfile;
> struct inode *new = NULL;
> + int out_buftype[2] = {};
> + struct kvec out_iov[2];
> struct kvec in_iov[2];
> int cmds[2];
> int rc;
> @@ -1228,7 +1230,7 @@ struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
> cmds[1] = SMB2_OP_POSIX_QUERY_INFO;
> cifs_get_writable_path(tcon, full_path, FIND_WR_ANY, &cfile);
> rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, &oparms,
> - in_iov, cmds, 2, cfile, NULL, NULL, NULL);
> + in_iov, cmds, 2, cfile, out_iov, out_buftype, NULL);
> if (!rc) {
> rc = smb311_posix_get_inode_info(&new, full_path,
> data, sb, xid);
> @@ -1237,12 +1239,27 @@ struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
> cmds[1] = SMB2_OP_QUERY_INFO;
> cifs_get_writable_path(tcon, full_path, FIND_WR_ANY, &cfile);
> rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, &oparms,
> - in_iov, cmds, 2, cfile, NULL, NULL, NULL);
> + in_iov, cmds, 2, cfile, out_iov, out_buftype, NULL);
> if (!rc) {
> rc = cifs_get_inode_info(&new, full_path,
> data, sb, xid, NULL);
> }
> }
> +
> + if (rc) {
> + /*
> + * If CREATE was successful but SMB2_OP_SET_REPARSE failed then
> + * remove the intermediate object created by CREATE. Otherwise
> + * empty object stay on the server when reparse call failed.
> + */
> + if (((struct smb2_hdr *)out_iov[0].iov_base)->Status == STATUS_SUCCESS &&
> + ((struct smb2_hdr *)out_iov[1].iov_base)->Status != STATUS_SUCCESS)
> + smb2_unlink(xid, tcon, full_path, cifs_sb, NULL);
> + }
You should handle the case where ->iov_base is NULL or out_buftype ==
CIFS_NO_BUFFER, otherwise you'll end up with a NULL ptr deref.
