[1518] in linux-security and linux-alert archive
[linux-security] /dev/random and MAKEDEV-C-1.6
daemon@ATHENA.MIT.EDU (David Holland)
Fri Apr 25 07:34:23 1997
From: David Holland <dholland@hcs.harvard.edu>
To: linux-security@redhat.com
Date: Thu, 24 Apr 1997 11:36:30 -0400 (EDT)
Resent-From: linux-security@redhat.com
Reply-To: linux-security@redhat.com
[Note: this has already been sent to comp.os.linux.announce.]
-----BEGIN PGP SIGNED MESSAGE-----
It has come to my attention that the recent 1.6 release of MAKEDEV-C
inadvertently created /dev/random and /dev/urandom with the wrong
permissions.
/dev/random and /dev/urandom should look like this:
crw-r--r-- 1 root system 1, 8 Feb 21 14:42 /dev/random
crw-r--r-- 1 root system 1, 9 Feb 21 14:42 /dev/urandom
If they do not, please do "chmod 644 /dev/random /dev/urandom".
**** This has potentially serious security implications.
**** Unrestricted write access to /dev/random and /dev/urandom
**** makes them cryptographically worse than useless.
If you have MAKEDEV-C-1.6 installed please get MAKEDEV-C-1.6.1, which
has just been uploaded to Sunsite and should appear in
/pub/Linux/system/admin. It can also be gotten from
ftp://ftp.hcs.harvard.edu/pub/linux/makedev.
Alternatively apply the following patch. You do not need to recompile
the makedev binary itself, but you do need to update the installed
devinfo and makedev.cfg files.
If you don't have pgp and don't know how to fix a patch that pgp has
signed, you can get the patch from the hcs ftp site, although I did
not upload it to sunsite.
If you have questions or concerns, feel free to mail me.
David A. Holland
dholland@hcs.harvard.edu
diff -r -u -N makedev-1.6/README makedev-1.6.1/README
- --- makedev-1.6/README Sat Feb 1 02:32:23 1997
+++ makedev-1.6.1/README Thu Apr 24 10:04:19 1997
@@ -6,6 +6,11 @@
/etc/devinfo. The config file is intended to be fairly human-readable,
as well as machine-readable.
+New in release 1.6.1:
+
+Correct permissions on /dev/random and /dev/urandom. This has security
+implications.
+
New in release 1.6:
The configuration files have been updated to reflect kernel 2.x, and
diff -r -u -N makedev-1.6/devinfo makedev-1.6.1/devinfo
- --- makedev-1.6/devinfo Sat Feb 1 02:22:15 1997
+++ makedev-1.6.1/devinfo Thu Apr 24 09:59:11 1997
@@ -104,8 +104,8 @@
zero (public) : 5
core -> "/proc/kcore"
full (public) : 7
- - random (public) : 8
- - urandom (public) : 9
+ random (publicro) : 8
+ urandom (publicro) : 9
}
block (std, 1) {
initrd (disk) : 250
diff -r -u -N makedev-1.6/makedev.cfg makedev-1.6.1/makedev.cfg
- --- makedev-1.6/makedev.cfg Sat Feb 1 02:23:58 1997
+++ makedev-1.6.1/makedev.cfg Thu Apr 24 09:58:53 1997
@@ -4,6 +4,7 @@
class default: root system 0640
class public: root system 0666
+class publicro: root system 0644
class system: root system 0660
class kmem: root kmem 0640
class tty: root tty 0620
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