• Hugh Dickins's avatar
    tmpfs,ceph,gfs2,isofs,reiserfs,xfs: fix fh_len checking · 35c2a7f4
    Hugh Dickins authored
    Fuzzing with trinity oopsed on the 1st instruction of shmem_fh_to_dentry(),
    	u64 inum = fid->raw[2];
    which is unhelpfully reported as at the end of shmem_alloc_inode():
    BUG: unable to handle kernel paging request at ffff880061cd3000
    IP: [<ffffffff812190d0>] shmem_alloc_inode+0x40/0x40
    Call Trace:
     [<ffffffff81488649>] ? exportfs_decode_fh+0x79/0x2d0
     [<ffffffff812d77c3>] do_handle_open+0x163/0x2c0
     [<ffffffff812d792c>] sys_open_by_handle_at+0xc/0x10
     [<ffffffff83a5f3f8>] tracesys+0xe1/0xe6
    Right, tmpfs is being stupid to access fid->raw[2] before validating that
    fh_len includes it: the buffer kmalloc'ed by do_sys_name_to_handle() may
    fall at the end of a page, and the next page not be present.
    But some other filesystems (ceph, gfs2, isofs, reiserfs, xfs) are being
    careless about fh_len too, in fh_to_dentry() and/or fh_to_parent(), and
    could oops in the same way: add the missing fh_len checks to those.
    Reported-by: default avatarSasha Levin <levinsasha928@gmail.com>
    Signed-off-by: default avatarHugh Dickins <hughd@google.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: Sage Weil <sage@inktank.com>
    Cc: Steven Whitehouse <swhiteho@redhat.com>
    Cc: Christoph Hellwig <hch@infradead.org>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
inode.c 92 KB