• Vivek Goyal's avatar
    ovl: append MAY_READ when diluting write checks · 500cac3c
    Vivek Goyal authored
    Right now we remove MAY_WRITE/MAY_APPEND bits from mask if realfile is on
    lower/. This is done as files on lower will never be written and will be
    copied up. But to copy up a file, mounter should have MAY_READ permission
    otherwise copy up will fail. So set MAY_READ in mask when MAY_WRITE is
    reset.
    
    Dan Walsh noticed this when he did access(lowerfile, W_OK) and it returned
    True (context mounts) but when he tried to actually write to file, it
    failed as mounter did not have permission on lower file.
    
    [SzM] don't set MAY_READ if only MAY_APPEND is set without MAY_WRITE; this
    won't trigger a copy-up.
    Reported-by: default avatarDan Walsh <dwalsh@redhat.com>
    Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
    Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
    500cac3c
inode.c 10.3 KB