Hello everyone,
I am trying to monitor the logs written into the system at boot time for a 15.5 SUSE Linux VM in order to gain information about the NICs (Network Interface Cards) configured into the system. This can be obtained using the dmesg or journalctl command but these require root privileges. Therefore, I am looking for the file in which these logs are stored and trying to read them directly. In my system, I discovered that these logs are stored in the /var/log/boot.msg file, however, some of the online articles and forums say that boot.msg and boot.log files have been deprecated. Also, it is not mentioned in this document listing the system log files in a SUSE environment.
Can someone shed some light on this? Has the boot.msg file has been deprecated and if yes, are there any other log files that I can use that store this information, or is there any other command that can be executed without root privileges to get this NICs-related information?
Thus any other program, being it cat or and editor or whatever will not be able to read them when not being executed as a root owned process (or by others belonging to the ‘root’ group). Seems logical to me. You protect those files against normal user access or not, independent of the tool used.
Hint: You are currently not seeing messages from other users and the system.
Users in the 'systemd-journal' group can see all messages. Pass -q to
turn off this notice.
and add group systemd-journal to your user that should have full read access to the journal,
What specific information are you looking for? It’s entirely possible that the info you’re looking for can be obtained in places other than in log files.
Without knowing what specific information you want, it’s hard to describe how to obtain it.
Actually, the end goal is to create a script that allows all types of users to collect information on the hardware components of the system. In order to get the information about the NIC type, I used the following command:
dmesg | grep -i ‘NIC’
This command works for all the users in Centos and older versions of Ubuntu, however, it seems that higher privileges are required to run the same command in SUSE Linux distributions as I face the following error in a newly created user in SUSE Linux:
Output from the Centos:
[devuser@co7-50-7-214 ~]$ dmesg | grep -i ‘NIC’
[ 1.283260] VMware vmxnet3 virtual NIC driver - version 1.4.17.0-k-NAPI
[ 1.284769] vmxnet3 0000:03:00.0 eth0: NIC Link is Up 10000 Mbps
[ 4.249812] vmxnet3 0000:03:00.0 ens160: NIC Link is Up 10000 Mbps
Output from the SUSE 15.5 using root privilege:
dev_user@suse15-50-3-170:/root> sudo dmesg | grep -i ‘NIC’
[ 5.466168] VMware vmxnet3 virtual NIC driver - version 1.5.0.0-k-NAPI
[ 5.468485] vmxnet3 0000:0b:00.0 eth0: NIC Link is Up 10000 Mbps
[ 7.277652] vmxnet3 0000:0b:00.0 eth0: NIC Link is Up 10000 Mbps
Output from the SUSE 15.5 with the newly created user (non-root):
dev_user@suse15-50-3-170:/root> dmesg
dmesg: read kernel buffer failed: Operation not permitted
Kindly let me know if you have any alternative that allows me to retrieve the above-mentioned information without requiring any additional permissions or capabilities for the normal user. Also, please let me know if a specific set of capabilities or permissions is required for normal users to get this information.
@sid_fultariya there is ip a and /sbin/lspci -nnk | grep -EA 3 "Ethernet" and as indicated, inxi which you can download the script and put in you $HOME bin directory.
dmesg is restricted now for security reasons - my guess is that it was determined that exposing information about the system to just any user allows an attacker to enumerate devices and do other things that could be used to compromise the system.
Chasing this a bit further (since this is debian, though I found posts about this for arch and other distros), the dmesg man page points to syslog(2), which explains:
All commands except 3 and 10 require privilege. In Linux kernels before Linux 2.6.37, command types 3 and 10 are
allowed to unprivileged processes; since Linux 2.6.37, these commands are allowed to unprivileged processes only if
/proc/sys/kernel/dmesg_restrict has the value 0. Before Linux 2.6.37, "privileged" means that the caller has the
CAP_SYS_ADMIN capability. Since Linux 2.6.37, "privileged" means that the caller has either the CAP_SYS_ADMIN ca‐
pability (now deprecated for this purpose) or the (new) CAP_SYSLOG capability.
See the syslog(2) manpage for details about the specifics.