Fedora Security :: Modifying Grub Kernel Arguments Boots Directly Into Root?

Jan 21, 2011

I updated the kernel to 2.6.35.10-74.fc14.x86_64 and had to reinstall and rebuild the kernel module for my ATi driver as usual, so I edited the kernel arguments at the grub splash screen so that I could boot into single user mode and install the driver (i.e appending the relevant line with '1'). The interesting thing is, the system booted directly into single user mode as root when the system started up. No password was required.

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OpenSUSE Install :: System Boots To Grub Instead Of Kernel?

Apr 14, 2010

I installed Fedora 13 on a separate partition and it deleted all of my openSUSE entries in grub. Or the boot menu, whichever is correct. From another thread, I found these commands and tried it:

Code:

grub
root (hd0,3)
setup (hd0)
quit
reboot

hd0,3 contained one of my openSUSE installs. Everything went well and grub accepted all of these commands except quit. So I used esc and rebooted. The reboot brought up the grub shell again. I could find no way to boot anything. Then I used the 'repair installation' option from the 11.2 dvd and installed a new boot loader for /dev/sda2 which contains 11.2.

This was successful, so I went to the YaST bootloader tool and added /dev/sda3 (Milestone 5) and /dev/sda4 (Fedora) and rebooted. But these two partitions still boot into grub instead of loading the correct kernel.

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Ubuntu Security :: How To Prevent Grub Command-line Boots

May 18, 2011

The ability to manually boot using the Grub command-line constitutes a big security risk in Linux, IMO.Any OS can be booted in this manner from a PXE-LAN, USB, or CD/DVD drive, circumventing BIOS-imposed boot restrictions. (Once a foreign OS is booted, of course, it can be used to access any part of an unencrypted hard drive.) Placing passwords or locking menu items (in the Grub configuration files) does not prevent a user from booting manually using commands entered at the grub command-line.

As it stands now, when presented with the Grub menu (or after bringing up a hidden Grub menu with the "ESC" key), a user only needs to hit "c" to enter the Grub command-line mode to facilitate any type of bootup whatsoever. (They can then enter manually the Grub commands to boot an OS on any device.) This is extremely insecure and allows any passerby to boot the computer with a few keystrokes and a bootable USB drive. How do I configure Grub so that it will require a password in order to enter the command-line mode (and thereby restrict boot options to the menu, which can then be password protected/locked) ?

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Fedora :: Can't Save Kernel Arguments

Jan 5, 2010

I am using an Acer Aspire Timeline 4810TZ with F12 installed. I have to enter the kernel argument intel_iommu=off each time I boot. This means pressing escape, going to the correct kernel, pressing A (to change kernel arguments), and then entering the command. I've seen some sources that suggest editing /boot/grub/grub.conf, but I've tried it and it doesn't seem to make a difference. I'm wondering if maybe there's another file that I have to edit, because I don't see the kernel arguments in grub.conf that I see when I press A in the grub menu.

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Fedora Security :: Reset The Root Password By Booting Into Single Usermode By Editing Grub

Apr 17, 2009

Being able to reset the root password by booting into single usermode by editing grub. This is a MAJOR flaw. I know it makes no real difference against internet bourne attacks, but even so I must say I found it shocking. The only way I've found to stop this is to encrypt the entire HDD, so noone could get into single user mode without first knowing the encryption key/password.

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Ubuntu :: Boots Directly But Not In A VM?

Jun 29, 2011

This is probably more of a VMware problem than an Ubuntu problem, but I am hoping that perhaps someone else running Ubuntu has experienced this and/or has insight.I have a dual-boot system running Win 7 and Ubuntu 11.04 (Both 64-bit).installed VMware Player in Windows 7 and created a virtual machine which should use the partition that Ubuntu is installed on. When I try to run the VM, the "bios" screen goes by and then I get an error message stating that "a virtual cpu has entered the shutdown state." I have tried changing the boot order to boot from cd-rom first and with the ubuntu cd in the drive, the vm will boot from cd and run. Note that I do run VMware Player as an administrator so that it should be allowed to access the hardware directly.

I have tried googling for this and searching VMware communities but pretty much all I find is relative to attempts to install Mac OS X Snow Leopard.Any help would be appreciated.(Note that I have a coworker who has done this successfully and we have compared notes and nothing is popping out as different from a basic configuration standpoint. We do however have different hardware as we are talking Dell Latitude Laptop (him) vs. Lenovo X201 Tablet (Me), both pretty new)

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Ubuntu :: 10.10 Kernel Updates Modifying Kernel Settings PenStick?

Jul 23, 2009

I have made a several modifications to my penstick running Xubuntu 10.10 that have greatly enhanced its performance. It took me several weeks to get to this point. I have added entries to /etc/rc.local and added kernel tweaks in /etc/grub.d/40_Custom so that my entries wont be erased. I have also added entries in my /etc/fstab. I have read this document in regards to the kernel but I am concerned about my /etc/fstab,/etc/rc.local and /etc/grub.d/40_Linux files being overwritten from updates.

[URL]

I am concerned about when one of my users decides he wants to run his updates via apt-get or package managers that all of the configs that I have done will be wiped away.

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Ubuntu :: System Directly Boots In Win 7

Aug 14, 2011

I installed ubuntu inside windows, thing were going good, till windows got affected with virus, so had to reinstall it, now boots directly in windows 7. I have a 500 GB HDD with two equal partitions,
C: drive has windows
D: drive has ubuntu
I tried the boot-repair, didn't work, instead it corrupted windows boot, which got fixed using startup recovery but I want ubuntu back...

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General :: Installed Driver For Graphics Card, Now It Boots Directly To Terminal?

Jan 4, 2011

Finished installing Ubuntu 10.10 in my XPS15, intel i5 4g ram, nvidia GT 420M graphics card,

problem is when i go to additional drivers, the driver listed (Nvidia accelerated graphics) when I install it and reboot it the computer starts on the terminal, no graphic interface. All I get is the black screen asking me login and password, when I enter them, just get the terminal prompt in a black screen.

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Fedora Networking :: How To Update Kernel Without Connecting To Internet Directly?

Sep 28, 2010

I recently installed F13 on my Toshiba Satellite C650. It has a buggy ACPI which no linux distro till date supports. I got that covered though. But my problem is that the ethernet port works only if the kernel is >=2.34. But F13 came with 2.33.

I do not have an access to a wireless network. Please tell me how to update the kernel without connecting to internet directly. I am new to Fedora. I have been using Ubuntu for some time and this can be achived in ubuntu by downloading the DEB packages and dependencies.

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Red Hat / Fedora :: Updated Kernel But Still Boots The Old?

Jun 16, 2010

I just finished an update on the kernel and it seems to be ok as shown in the grub:

Code:

default=0
timeout=5
splashimage=(hd0,8)/boot/grub/splash.xpm.gz

[code]...

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Software :: Modifying GRUB Stage1

Jan 12, 2011

Hi All,

I am using legacy grub(0.9.7) as my boot loader. I want to add some code into GRUB stage1. But I am getting following error.

stage1.S: Assembler messages:
stage1.S:591: Error: attempt to move .org backwards
stage1.S:603: Error: attempt to move .org backwards
make[2]: *** [stage1.o] Error 1

It seems like Stage1 code is starting after BPB only. Is it possible to use BPB section for GRUB stage1 (GRUB is installed in HDD)??

If yes, how to change the code start to BPB section??

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Programming :: Modifying The Elevator.c Module In Kernel?

Feb 22, 2011

There is a file called elevator.c. It is written as a module (i.e it has specific init and exit functions). However we are not able to see it in lsmod listing. We are working on a project where we need to modify this file. Compiling every time we change something will be time consuming. Is it possible to compile just this file and insert it as a normal module?

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Fedora :: F11 Boots To Wallpaper But No Gnome After 2.6.30.5-43 Kernel Update

Sep 8, 2009

Applied several updates last night including a 2.6.30.5-43 kernel and a suggest kmod-nvidia but the 5-43 kernel boots to a wallpaper gnome screen the first time.

Booted to the "fallback" 2.6.29....17 kernel and it worked fine.

Then 2.6.30.5.-43 also booted but without nvidia.

Installing akmod-nvidia as sugggested in other posts. Also see a kmod for this kernel.

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CentOS 5 :: Modifying Repo File To Convert Kernel

Jul 9, 2010

I am trying to convert from using the base centos kernel to centosplus kernel. I have modified the CentoOS-Base.repo file to do this, including ensuring that I have excluded the kernel kernel-devel etc from base and updates. However when I do a yum update there is nothing to update. I have noted that my current kernel is kernel-2.6.18-194.8.1 whereas the current centosplus kernel seems to be 2.6.18-194.3.1. I presume that the problem is that the plus kernel is not as recent as the base kernel. Is this correct? What is the best way of converting to the centosplus kernel in these circumstances?

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Security :: Kernel Flaw Coughs Up Root Rights

Oct 21, 2010

Quote: The open-source Linux operating system contains a serious security flaw that can be exploited to gain superuser rights on a target system. The vulnerability, in the Linux implementation of the Reliable Datagram Sockets (RDS) protocol, affects unpatched versions of the Linux kernel, starting from 2.6.30, where the RDS protocol was first included.

According to VSR Security, the research outfit that discovered the security hole, Linux installations are only vulnerable if the CONFIG_RDS kernel configuration option is set, and if there are no restrictions on unprivileged users loading packet family modules, as is the case on most stock distributions.

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Fedora Installation :: Grub Boots Win7 But Doesnt F13 X64?

Jun 8, 2010

Im a newbie having the opposite issue that seems that everyone is having for what Ive seen, I have Grub on the MBR, showing the splash screen fine (the background image also), and allowing me to boot Windows 7, but I get a cursor blinking for the eternity when trying to boot Fedora 13.My hardware is:

Quote:

-ASUS M4A89GTD PRO (AMD 890 FX AM3 Chipset).
-Phenom 965 BE.
-4Gb RAM.
-3 x 250 Gb SATA Hard disks, first one alone for OS, and the other two in fake RAID1.
-1 x 80 Gb IDE hard drive containing trash.
-RADEON HD 4870 1Gb Graphic Card.
-RME HDSP 9632 Soundcard

[Code]...

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CentOS 5 :: Specify Root Option For Kernel Command Of Grub Conf

Feb 12, 2010

I'm using 2 cloned disks with CentOs5.3 and I need to be able to control which one is booted. I can specify which disk in the BIOS but after stage 2 it is always running from disk 2. When I have puppy linux on one disk and CentOs on the other I can boot off of either as selected by the system BIOS so the BIOS is not the issue. I think it is how the root option is passed in the kernel command in the grub.conf.

kernel /vmlinuz-2.6.18-128.el5 ro root=/dev/VolGroup00/LogVol00

I think when the OS searches for the /dev/VolGroup00/LogVol00 share is locates 2 since the disks are clones and uses the last one found. On information I have found for the kernel command and the root option it appears CentOs uses it differently. CentOs uses a volume name as specified /dev/VolGroup00/LogVol00 instead of a partition designator /dev/hda2. Is there a different way to specify /dev/VolGroup00/LogVol00 in CentOS for the root option for the kernel command of grub.conf?

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Fedora Installation :: Dual Boot Only Boots Into XP - Create Grub At Start?

Dec 20, 2010

I have Fedora 13 and XP installed on my laptop. Right now it only boots to XP but I have a Fedora Live CD so is there some way I can use the live cd to boot into Fedora and edit or install grub to show up at boot?

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Software :: Unable To Boot Into GRUB Loader: GRUB Command Shell Boots Up?

Sep 2, 2009

A failed upgrade, from disk images, of Fedora 10 to 11 resulted in no GRUB bootloader main menu appearing on bootup (no WIN, no LINUX choices from which to boot). I am booted directly into the GRUB command shell...so, no WIN, no LINUX, nothing. And my understanding of GRUB shell commands is very low.I have 2 hard disks, WIN on the first, LINUX on the second. I believe GRUB Bootloader is on the first disk.Sadly, I have no external install media.An old grub.conf hardcopy indicates that root =/dev/sdb2, root (hd1,0), kernel /vmlinuz....olderversion...(relative to /boot),initrd /initrd...olderversion... (relative to boot). and WINDOWS on (hd0,1), with chainloader +1

I need to somehow get past this grub shell, and re-install/re-instate the grub bootloader, so it can boot normally.What grub command(s) must I use? I've played around with the commands, but with no success.I worry that if I can't resolve this, the whole machine may be useless.

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Ubuntu Installation :: GRUB Doesn't Detect Kernel After Security Upgrades

Feb 10, 2010

I have just suscribed into this forum. I have a problem: my notebook (NOTEBOOK SATELLITE L300-SP5917A - INTEL CORE 2 DUO T6400 (2.00 GHZ - 2 MB L2 - 800MHZ FSB) - 15.4 WIDESCREEN TRUBRITE TFT LCD - 400 GB SATA 2 .5 5400 RPM - 3GB PC2-6400 DDR2) doesn't boot ubuntu after the last security upgrade. I have wubi installed.I have Windows Vista and Ubuntu in the boot menu. I select "Ubuntu" and that leads me to the GRUB shell. I'm new in linux. It seems that GRUB doesn't detect the kernel. Maybe the file menu.lst has been deleted, or something similar, but I can't make my ubuntu to boot.

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Fedora Security :: Become Root Without Root Password?

Oct 20, 2010

I found this on Bee's website. For more info on this exploit there are links there:[URl]..All you have to do in Fedora 13 is enter the following lines in a shell as normal user:

[Code]...

I don't think this can be considered solely an "upstream" problem, because I first tried it in Arch using the same version of glibc, and the final command causes both gnome-terminal and xterm windows to disappear.

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Fedora :: Cold Boots Often Take Up To 10 Attempts Before The Computer Successfully Boots?

Oct 29, 2010

my desktop pc is acting very strange. cold boots often take up to 10 attempts before the computer successfully boots. after the 1st successful boot, i can expect 1-3 "glitches". here's what happens:

the first few cold boots fail at various points during the boot process. there appears to be no pattern to it. when it happens, the machine is completely locked up. it responds to nothing, except holding in the power switch for 5 seconds. i'll go through this procedure several times.

finally, it will boot all the way to a desktop. from there, once i log it, i can expect it to lock up completely, usually once or twice. and then, finally, the screen will go blank and it will suddenly be back at the login screen.

usually, once i log in that last time, it's at least usable, although hardly stable. watching flash video seems to cause a complete lockup, with the sound looping. it doesn't matter where the content is coming from (videos or similar) nor does it matter which browser i'm using (firefox or chrome). i've stopped visiting videos-type sites in the meantime.

this installation has always been a tad bit screwy. 99% of the time, firefox fails to shut down properly, resulting in a message letting me know that a crash was detected. earlier today, i was alerted to 3 kernel crashes simultaneously.

right now, i'm using the pc, as normal. the random nature of the problems would lead me to believe it was hardware-related, specifically something like memory (ram). however, i installed memtest86+ and ran it. i walked away for 4+ hours. came back, it was running, no errors were found. i stopped the test and booted, trouble-free.

the pc seems to be stable enough for a backup, but this does have me concerned...obviously. i'm debating wiping the drive clean and installing f13, just as a test. if it's screwy as well, it would have to be hardware-related, wouldn't you think??

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Ubuntu Security :: Grub With Luks Support - Encrypting The Boot Partition To Prevent The Kernel From Being Modified?

Mar 9, 2011

Has anyone tried encrypting the boot partition to prevent the kernel from being modified. Iv tried following this but I'm running into issues when building. [URL] Im using the source from bzr checkout [URL] Last time I tried I screwed grub and it wouldnt boot.

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General :: Root Login Directly Into -bash-3.2#?

Mar 22, 2010

i am using fedora 10 while i login as a normal user its working fine username@hostname while i login as a root user it goes directly into -bash-3.2# if i check pwd it shows /root till now i am not facing any problem as i am using as a normal user but how can i change -bash-3.2# to root@hostname which file and where to edit

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Ubuntu :: Booting W7 Directly From Grub?

Jul 8, 2011

I installed Ubuntu on w7 using Wubi and I set in w7 that it on startup automatically boots Grub without asking. Now when I am in Grub and when I select Windows 7 (loader) it goes black and returns to Grub so I cant boot w7 at all.

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Ubuntu :: Grub2 Editing - Editing Directly To /boot/grub/grub.cfg?

Jun 6, 2010

I have an old laptop that I installed EasyPeasy Lucid on. I have never used Grub2 as my other Ubuntu installs still use Grub Legacy. I have studied all the tutorials which instruct that the grub.cfg file should not be edited directly.This old laptop has one of the dreaded Intel graphics chips for which the kernel automatically loads the i915 module. Of course (like a multitude of others with Intel graphics and Lucid) I booted into a black screen but knew the workaround was to enable mode setting through grubI used the

Code:
i915.modeset=1
and added it to /etc/default/grub line GRUB_CMDLINE_LINUX, just after "quite splash", just

[code]....

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General :: Root User Must Not Be Allowed To Directly Login To Service Console?

May 12, 2011

I want to set security regarding with the root user. The root user must not be allowed to login directly to the service console, how will I do this?

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Ubuntu :: Grub Goes Directly To Prompt (No Menu)

Oct 30, 2010

I rebooted my computer recently after installing some updates in Ubuntu and now when grub launches it goes straight to the grub prompt and I don't get a menu. I tried searching around online and have tried what seemed like the most common fix but to no avail:
find /boot/grub/stage1 (returns hd1,0)
root (hd1,0)
setup (hd0) -I also tried (hd1,0) and (hd1)
-then reboot- (still get no menu and goes straight to the prompt)

I then tried booting into Ubuntu live, using apt-get to install Grub, and then running through the install process using similar commands, but to no avail. When I run setup it finds my config info and doesn't show any errors. I have a menu.lst file with lots of entries for different kernel versions and a windows 7 install on hd0,0. I am running Ubuntu Ubuntu 10.04.1 LTS, kernel 2.6.32-25-generic-pae.

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General :: Directly Logging In As Root In A Text Mode Terminal (tty1-tty6)?

May 13, 2010

What are the differences between "su -" in a GUI terminal and directly logging in as root in a text mode terminal (tty1-tty6)? Any environment, path or other functionality differences?

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