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Revision 3958b79266b14729edd61daf9dfb84de45f4ec6d authored by Nicolas Iooss on 17 July 2015, 23:23:45 UTC, committed by Linus Torvalds on 17 July 2015, 23:39:53 UTC 
configfs: fix kernel infoleak through user-controlled format string
 
Some modules call config_item_init_type_name() and config_group_init_type_name()
with parameter "name" directly controlled by userspace.  These two
functions call config_item_set_name() with this name used as a format
string, which can be used to leak information such as content of the
stack to userspace.

For example, make_netconsole_target() in netconsole module calls
config_item_init_type_name() with the name of a newly-created directory.
This means that the following commands give some unexpected output, with
configfs mounted in /sys/kernel/config/ and on a system with a
configured eth0 ethernet interface:

    # modprobe netconsole
    # mkdir /sys/kernel/config/netconsole/target_%lx
    # echo eth0 > /sys/kernel/config/netconsole/target_%lx/dev_name
    # echo 1 > /sys/kernel/config/netconsole/target_%lx/enabled
    # echo eth0 > /sys/kernel/config/netconsole/target_%lx/dev_name
    # dmesg |tail -n1
    [  142.697668] netconsole: target (target_ffffffffc0ae8080) is
    enabled, disable to update parameters

The directory name is correct but %lx has been interpreted in the
internal item name, displayed here in the error message used by
store_dev_name() in drivers/net/netconsole.c.

To fix this, update every caller of config_item_set_name to use "%s"
when operating on untrusted input.

This issue was found using -Wformat-security gcc flag, once a __printf
attribute has been added to config_item_set_name().

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <balbi@ti.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 8db1486
Raw File
hv_set_ifconfig.sh 
#!/bin/bash

# This example script activates an interface based on the specified
# configuration.
#
# In the interest of keeping the KVP daemon code free of distro specific
# information; the kvp daemon code invokes this external script to configure
# the interface.
#
# The only argument to this script is the configuration file that is to
# be used to configure the interface.
#
# Each Distro is expected to implement this script in a distro specific
# fashion. For instance on Distros that ship with Network Manager enabled,
# this script can be based on the Network Manager APIs for configuring the
# interface.
#
# This example script is based on a RHEL environment.
#
# Here is the format of the ip configuration file:
#
# HWADDR=macaddr
# DEVICE=interface name
# BOOTPROTO=<protocol> (where <protocol> is "dhcp" if DHCP is configured
#                       or "none" if no boot-time protocol should be used)
#
# IPADDR0=ipaddr1
# IPADDR1=ipaddr2
# IPADDRx=ipaddry (where y = x + 1)
#
# NETMASK0=netmask1
# NETMASKx=netmasky (where y = x + 1)
#
# GATEWAY=ipaddr1
# GATEWAYx=ipaddry (where y = x + 1)
#
# DNSx=ipaddrx (where first DNS address is tagged as DNS1 etc)
#
# IPV6 addresses will be tagged as IPV6ADDR, IPV6 gateway will be
# tagged as IPV6_DEFAULTGW and IPV6 NETMASK will be tagged as
# IPV6NETMASK.
#
# The host can specify multiple ipv4 and ipv6 addresses to be
# configured for the interface. Furthermore, the configuration
# needs to be persistent. A subsequent GET call on the interface
# is expected to return the configuration that is set via the SET
# call.
#



echo "IPV6INIT=yes" >> $1
echo "NM_CONTROLLED=no" >> $1
echo "PEERDNS=yes" >> $1
echo "ONBOOT=yes" >> $1


cp $1 /etc/sysconfig/network-scripts/


interface=$(echo $1 | awk -F - '{ print $2 }')

/sbin/ifdown $interface 2>/dev/null
/sbin/ifup $interface 2>/dev/null
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