BIND 9.4.x vs 9.6.x - pid-file check and creation

Mark Andrews Mark_Andrews at isc.org
Mon Jan 26 08:33:00 UTC 2009


In message <200901260742.n0Q7gJqN029792 at mail46.nsc.no>, Jan Arild =?iso-8859-1?
Q?Lindstr=F8m?= writes:
> 
> Hi,
> 
> I was going to upgrade from BIND 9.4.3 to BIND 9.6.0-P1, but run into a =
> 
> strange "bug" in BIND 9.6.0-P1.
> 
> Exact same config for 9.4.3 and 9.6.0-P1, only added "new" to files that =
> 
> are written to (namednew.log, confignew.log and namednew.pid).
> 
> OS: Solaris 10.
> 
> Using:
>         pid-file "/var/run/named/namednew.pid";
> 
> .. result in the following:
> 
> namednew.log:
> 26-Jan-2009 08:14:22.723 general: couldn't mkdir /var/run/named/namednew.pi=
> d': Permission denied
> 26-Jan-2009 08:14:22.728 general: exiting (due to early fatal error)

	The log message should say couldn't mkdir /var/run/named.
	The wrong path is being logged.

	You either need to create /var/run/named with appropriate
	permissions so that named can write to it or change /var/run's
	permissions so that named can create /var/run/named.

	Named will continue if mkdir(/var/run/named) returns EEXISTS.
 
	Mark

        /*
         * Make the containing directory if it doesn't exist.
         */
        slash = strrchr(pidfile, '/');
        if (slash != NULL && slash != pidfile) {
                *slash = '\0';
                mode = S_IRUSR | S_IWUSR | S_IXUSR;     /* u=rwx */
                mode |= S_IRGRP | S_IXGRP;              /* g=rx */
                mode |= S_IROTH | S_IXOTH;              /* o=rx */
                n = mkdir(pidfile, mode);
                if (n == -1 && errno != EEXIST) {
                        isc__strerror(errno, strbuf, sizeof(strbuf));
                        (*report)("couldn't mkdir %s': %s", filename,
                                  strbuf);
                        free(pidfile);
                        pidfile = NULL;
                        return;
                }
                *slash = '/';
        }

> BIND 9.6.0-P1 truss.out:
> --CUT--
> 25123/65:       stat("/dev/urandom", 0xFFFFFFFF79D0FA00)        =3D 0
> 25123/65:       open("/dev/urandom", O_RDONLY|O_NONBLOCK)       =3D 9
> 25123/65:       fcntl(9, F_GETFL)                               =3D 8320
> 25123/65:       fcntl(9, F_SETFL, FOFFMAX|FNONBLOCK)            =3D 0
> 25123/65:       setgid(21)                                      =3D 0
> 25123/65:       setuid(21)                                      =3D 0
> 25123/65:       access(".", W_OK)                               =3D 0
> 25123/65:       open("/var/log/namednew.log", O_WRONLY|O_APPEND|O_CREAT, 06=
> 66) =3D 10
> 25123/65:       lseek(10, 0, SEEK_END)                          =3D 332
> 25123/65:       close(10)                                       =3D 0
> 25123/65:       open("/var/log/confignew.log", O_WRONLY|O_APPEND|O_CREAT, 0=
> 666) =3D 10
> 25123/65:       lseek(10, 0, SEEK_END)                          =3D 0
> 25123/65:       close(10)                                       =3D 0
> 25123/65:       mkdir("/var/run/named", 0755)                   Err#13 EACC=
> ES [ALL]
> 25123/65:       stat("/var/log/namednew.log", 0xFFFFFFFF79D0F3C0) =3D 0
> 25123/65:       open("/var/log/namednew.log", O_WRONLY|O_APPEND|O_CREAT, 06=
> 66) =3D 10
> 25123/65:       lseek(10, 0, SEEK_END)                          =3D 332
> 25123/65:       fstat(10, 0xFFFFFFFF79D0E540)                   =3D 0
> 25123/65:       fstat(10, 0xFFFFFFFF79D0E410)                   =3D 0
> 25123/65:       ioctl(10, TCGETA, 0xFFFFFFFF79D0E47C)           Err#25 ENOT=
> TY
> 25123/65:       write(10, 0x10502E754, 97)                      =3D 97
> 25123/65:          2 6 - J a n - 2 0 0 9   0 8 : 1 4 : 2 2 . 7 2 3   g e n =
> e r a l
> 25123/65:          :   c o u l d n ' t   m k d i r   / v a r / r u n / n a =
> m e d /
> 25123/65:          n a m e d n e w . p i d ' :   P e r m i s s i o n   d e =
> n i e d
> 25123/65:         \n
> 25123/65:       write(10, 0x10502E754, 69)                      =3D 69
> 25123/65:          2 6 - J a n - 2 0 0 9   0 8 : 1 4 : 2 2 . 7 2 8   g e n =
> e r a l
> 25123/65:          :   e x i t i n g   ( d u e   t o   e a r l y   f a t a =
> l   e r
> 25123/65:          r o r )\n
> 25123/65:       _exit(1)
> 
> It fails because it tries to just create the /var/run/named directory inste=
> ad
> of cheking if the directory exist and if it can write to it. =
> 
> 
> ns12(root) named 515# ls -la /var/run/named
> total 40
> drwxr-s---    4 named    named         307 Jan 26 06:51 ./
> drwxr-xr-x    7 root     sys          1285 Jan 26 00:52 ../
> -rw-r--r--    1 named    named           6 Jan 26 06:41 named.pid
> 
> So /var/run/named exists and is fully writable by user named.
> 
> User "named" should of course not be able to crate diretories below
> "/var/run". Especially since many other things on Solaris 10 uses that
> directory also.
> 
> 
> If I use:
> 	pid-file "/var/run/named/named/namednew.pid";
> 
> ... everything works fine, since it now can run mkdir without getting "EACC=
> ES". =
> 
> Instead it gets "EEXIST" and is OK with that.
> 
> BIND 9.6.0-P1 truss.out:
> --CUT--
> 25404/65:       stat("/dev/urandom", 0xFFFFFFFF79D0FA00)        =3D 0
> 25404/65:       open("/dev/urandom", O_RDONLY|O_NONBLOCK)       =3D 9
> 25404/65:       fcntl(9, F_GETFL)                               =3D 8320
> 25404/65:       fcntl(9, F_SETFL, FOFFMAX|FNONBLOCK)            =3D 0
> 25404/65:       setgid(21)                                      =3D 0
> 25404/65:       setuid(21)                                      =3D 0
> 25404/65:       access(".", W_OK)                               =3D 0
> 25404/65:       open("/var/log/namednew.log", O_WRONLY|O_APPEND|O_CREAT, 06=
> 66) =3D 10
> 25404/65:       lseek(10, 0, SEEK_END)                          =3D 498
> 25404/65:       close(10)                                       =3D 0
> 25404/65:       open("/var/log/confignew.log", O_WRONLY|O_APPEND|O_CREAT, 0=
> 666) =3D 10
> 25404/65:       lseek(10, 0, SEEK_END)                          =3D 0
> 25404/65:       close(10)                                       =3D 0
> 25404/65:       mkdir("/var/run/named/named", 0755)             Err#17 EEXI=
> ST
> 25404/65:       stat("/var/run/named/named/namednew.pid", 0xFFFFFFFF79D0F98=
> 0) Err#2 ENOENT
> 25404/65:       unlink("/var/run/named/named/namednew.pid")     Err#2 ENOENT
> 25404/65:       open("/var/run/named/named/namednew.pid", O_WRONLY|O_CREAT|=
> O_EXCL, 0644) =3D 10
> 25404/65:       fcntl(10, F_GETFD, 0x000001A4)                  =3D 0
> 25404/65:       getpid()                                        =3D 25404 [=
> 25403]
> 25404/65:       fstat(10, 0xFFFFFFFF79D0E9D0)                   =3D 0
> 25404/65:       fstat(10, 0xFFFFFFFF79D0E8A0)                   =3D 0
> 25404/65:       ioctl(10, TCGETA, 0xFFFFFFFF79D0E90C)           Err#25 ENOT=
> TY
> 25404/65:       write(10, " 2 5 4 0 4\n", 6)                    =3D 6
> 25404/65:       close(10)                                       =3D 0
> --CUT--
> 
> 
> Trussing 9.4.3 I see that it does it differently:
> 
> --CUT--
> 25730/10:       access(".", W_OK)                               =3D 0
> 25730/10:       open("/var/log/namednew.log", O_WRONLY|O_APPEND|O_CREAT, 06=
> 66) =3D 10
> 25730/10:       lseek(10, 0, SEEK_END)                          =3D 2625
> 25730/10:       close(10)                                       =3D 0
> 25730/10:       open("/var/log/confignew.log", O_WRONLY|O_APPEND|O_CREAT, 0=
> 666) =3D 10
> 25730/10:       lseek(10, 0, SEEK_END)                          =3D 0
> 25730/10:       close(10)                                       =3D 0
> 25730/10:       stat("/var/run/named/namednew.pid", 0xFFFFFFFF7D90F660) Err=
> #2 ENOENT
> 25730/10:       unlink("/var/run/named/namednew.pid")           Err#2 ENOENT
> 25730/10:       open("/var/run/named/namednew.pid", O_WRONLY|O_CREAT|O_EXCL=
> , 0644) =3D 10
> 25730/10:       fcntl(10, F_GETFD, 0x000001A4)                  =3D 0
> 25730/10:       getpid()                                        =3D 25730 [=
> 25729]
> 25730/10:       fstat(10, 0xFFFFFFFF7D90E6B0)                   =3D 0
> 25730/10:       fstat(10, 0xFFFFFFFF7D90E580)                   =3D 0
> 25730/10:       ioctl(10, TCGETA, 0xFFFFFFFF7D90E5EC)           Err#25 ENOT=
> TY
> 25730/10:       write(10, " 2 5 7 3 0\n", 6)                    =3D 6
> --CUT--
> 
> 
> It seems that someone has "shorted" the code to create and/or check the pid=
> -file.
> 
> Maybe that "shortcut" will work on Linux, but it for sure does not work on =
> Solaris 10.
> 
> Having to use .../named/named/... in the pid-file option is of course possi=
> ble, but I =
> 
> guess that it is not the way it is supposed to be...(?)...
> 
> Help? Ideas?
> 
> Regards
> Jan Arild Lindstr=F8m
> 
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-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org



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