I'm working with some basic stack overflows. The following code compiles & runs fine in a non-ubuntu VM that's has no security features installed. On Ubuntu 10.04 it segfaults every time. I'm compiling on Ubuntu with the gcc -fno-stack-protector flag. If someone could point me to the security feature that's causing the segfaults (and how to disable it),
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I want to update the percentage progress of my program on the screen. I have a progress bar that I print. I add a * when the progress is more than 10%, but I also want to write the actual percentage correct up to every digit. However, I do not want to write a new number every time, since it will have the following effect:
1
2
3
4
Instead, I would like to just maintain one single figure on the screen that keeps getting updated. How do I do that? (... in Java/C++, but I think it's irrelevant)
I have to give it up for the Ubuntu developers. It is nearly impossible to exploit a simple stack overflow. I'm studying overflows for a project so I need it to work. I set /proc/sys/kernel/randomize_va_space to 0 and when I compiled my program I used -mpreferred-stack-boundary=2 and -fno-stack-protector. But for some reason no matter how much input I enter it won't overwrite the EIP. What is stopping this from working that other linux versions don't have? And does anyone know of a way to bypass it?
View 1 Replies View RelatedI would like to start learning about the nuts and bolts concerning Linux security. I bought the "Gray Hat Hacking" book by Harris et al. and started working at their example for buffer overflows but hit a bump immediately. Is this the right place to be discussing this sort of thing? If so I give pertinent info below:
Program:
//overflow.c
#include <string.h>
main(){
char str1[10]; //declare a 10 byte string
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I am trying to learn how a buffer overflow works, but I need to have an executable stack for it to work. How do i enable this for an individual program? I am using Arch linux and X86_64 btw
View 3 Replies View RelatedI am looking for an screen capture application which auto runs when ubuntu starts up and work without any instructions or clicking capture or anything,
= "Some1" ** Turns on the System --> UBUNTU Loads --> the Screen capture Runs--> it takes screen shots with out "Some1"s knowledge// turns off system....
I get home -->> turn on system -->> screen shots r saved.. n um checking em...!!!
Every once in a while (at least once a day; my computer is on 24/7) nautilus segfaults for no particular reason. Relevant lines from kern.log:
Code:
[1025306.206524] nautilus[4932]: segfault at 14 ip 00007f21e272f681 sp 00007fff15d60020 error 4 in libgtk-x11-2.0.so.0.2200.0[7f21e266c000+412000]
[1036388.690123] nautilus[22488]: segfault at 14 ip 00007fdfac3f5bcf sp 00007ffffc3d0220 error 4 in libgtk-x11-2.0.so.0.2200.0[7fdfac336000+412000]
[1277941.447685] nautilus[6944]: segfault at 14 ip 00007f01c578b681 sp 00007fffb95aed40 error 4 in libgtk-x11-2.0.so.0.2200.0[7f01c56c8000+412000]
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I've been happily using jaunty until yesterday. After reinstalling kubuntu to natty everything works fine except leafpad:
nick@rilmir:~$ sudo leafpad
[sudo] password for nick:
nick@rilmir:~$ leafpad
Segmentation fault
nick@rilmir:~$
So, when I run it as root, it works, but when I run it as ordinary user, it segfaults.Where do I even start looking?
Does anyone know what happened to the Multiseat feature that had been in the feature list at one point?To briefly summarise, a single machine with multiple graphics cards, sound cards, keyboards & mice provides multiple seats for users. Each user gets their own monitor, keyboard, mouse & perhaps audio. The rest of the machine resources are then shared.
The last I saw on the topic was this discussion, although I have a recollection that there was going to be support in a newer version of X.Org. I've googled around quite a bit, but can't seem to find anything.
Anybody know anything? It would be a great feature to have and it's frustrating to have had such an omission since F8 :-o
I have been looking for a while and I am unable to find an answer to yum segfaulting.
I have tried:
yum clean all
rm -f /var/lib/rpm/__*
rpm --rebuilddb
I tried upgrading yum and rpm to the newest versions in 5.5 and I still run into the same problem.
fcntl64(6, F_SETLK64, {type=F_RDLCK, whence=SEEK_SET, start=1073741824, len=1}, 0xbfcaf694) = 0
fcntl64(6, F_SETLK64, {type=F_RDLCK, whence=SEEK_SET, start=1073741826, len=510}, 0xbfcaf694) = 0
fcntl64(6, F_SETLK64, {type=F_UNLCK, whence=SEEK_SET, start=1073741824, len=1}, 0xbfcaf694) = 0
access("/var/cache/yum/base/primary.xml.gz.sqlite-journal", F_OK) = -1 ENOENT (No such file or directory)
fstat64(6, {st_mode=S_IFREG|0644, st_size=20480, ...}) = 0
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However, every time snmptrapd gets a snmp notification, it aborts. In debug mode, it reports a buffer overflow detected. I've tried another core 13 and a core 12, with net-snmp 5.5. On these three systems, snmptrapd behaves the same. Here is my snmptrapd.conf,
disableAuthorization yes traphandle default touch /root/a.txt I triggered snmptrapd with, snmptrap -Ci -v 2c -c public localhost "" "1.3.6.1.4.1.8837.4.1.2.1.2.1.6.4" 1.3.6.1.4.1.8837.4.1.2.1.2.1.6.4 int 500 Same result I got with my firewall snmp traps. Some other different scripts replaced in traphandle default, got the same. A small portion of debug info listed,
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Did Walnut Creek overflow its banks and swallow up theSlackware.com Domain name??Pat Volkerding Danger
View 3 Replies View RelatedI'm using Core13 for zabbix, and trying to make snmptrapd works on it.
However, every time snmptrapd gets a snmp notification, it aborts. In debug mode, it reports a buffer overflow detected. I've tried another core 13 and a core 12, with net-snmp 5.5. On these three systems, snmptrapd behaves the same.
Here is my snmptrapd.conf,
disableAuthorization yes
traphandle default touch /root/a.txt
I triggered snmptrapd with,
snmptrap -Ci -v 2c -c public localhost "" "1.3.6.1.4.1.8837.4.1.2.1.2.1.6.4" 1.3.6.1.4.1.8837.4.1.2.1.2.1.6.4 int 500
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I have installed ubuntu 9.10 64-bit and MATLAB 7.3 _x86-64.When I run matlab launching script I get this error message and the program freezes:
/usr/local/matlab7.3/bin/glnxa64/MATLAB: Symbol `__kmp_test_then_add_real32' causes overflow in R_X86_64_PC32 relocation
/usr/local/matlab7.3/bin/glnxa64/MATLAB: Symbol `__kmp_test_then_add_real64' causes overflow in R_X86_64_PC32 relocation.
I tried to run "matlab -nojvm" and I get the same error as above but the program starts and seems to work smoothly. The problem is that I cannot run the editor and debug scripts and functions
It crash giving this error: "Whoops! the applet crashed. Click to restart it" while i set Layout "curved gui"
And then i try to change its setting by clicking on "Layout settings".
Sometimes im able to get inside "layout settings" but then it crush when i switch
to another tab.
What to do for to solve this issue? Is some other way to configure it (maybe through terminal)
Or exist some better stack applet (mac like)
İ have nvidia fx 5200. when i was install my driver resolution stack at 640x480 and i cant change to 1024x768.
View 1 Replies View RelatedI have always in the past installed and configured my own mail server with Postfix, Fetchmail, Procmail and Dovecot. I know that for a while the Ubuntu server team have developed their own server stack and so I decided to give it a go with my new 11.04 installation. However, when I look on Synaptic I see that there are two mail server stacks.
mail-stack-delivery
and
dovecot-postfix
Both are described as
"mail server delivery agent stack provided by the Ubuntu server team"
What is the difference between the two stacks?
I have updated my computer to Kubuntu 10.10 (which has the new firewire stack enabled by default) and now my firewire application is giving permission related problems. I try to read CSR_CHANNELS_AVAILABLE_HI (defined in libraw1394 which is used by the application) to see which isochronous channels are available to use:
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With the old stack (raw1394) there are not problems and it runs fine and I get the octlet back containing the information about the free channels. But with the new stack (firewire_core and friends) I get a 'permission denied' (errno = 1) error. I do have permission to read/write /dev/fw* and I even tried running the application as root without any luck. If I read the config rom of a node (located at CSR_CONFIG_ROM) there are no permission problems and I am able to get the information/ What am I doing wrong? Did something change with the new stack (even though libraw1394 should be compatible with both stacks)? Is it a bug?
Desperate to reduce RAM usage of my tiny VPS running Ubuntu 9.04 and Apache2.2.11, here I saw that:
On Linux, each child process will use 8MB of memory by default. This is probably unnecessary. You can decrease the overall memory used by Apache by setting ThreadStackSize used by Apache by setting ThreadStackSize to 1MB in.
So I tried to give the suggestion a try. But when I append:
ThreadStackSize 1000000
in my /etc/apache2/httpd.conf <IfModule mpm_prefork_module> directive, and restarted apache, it failed with this message:
Invalid command 'ThreadStackSize', perhaps misspelled or defined by a module not included in the server configuration
So I figured out that the relevant modules are neither enabled nor available on apache2. Now I am wondering whether there is a way to decrease the ThreadStackSize without the need to compile apache from source? If not, what should I do?
how to disable rSIM in the current bluetooth stack?Starting about a week ago, whenever my phone (Android Captivate) pairs with my ubuntu workstation the rSIM profile is enabled which effectively turns off my cell service since my Ubuntu machine does not have a GSM/3G radio built in.I'd like to disable rSIM altogether so that I can again re-pair my phone to my Linux system. All my searching turn up results for people trying FIX this service...
View 2 Replies View Relatedhow the current full desktop stack looks like for Ubuntu Natty? I assume it should roughly look like this:
Unity
Compiz
Gnome
X
Is this correct? Any other levels that I missed? Where would Wayland stand (in the future) here? I assume it will just replace X?
My ubuntu 11.04 installation has been crashing a lot with random stack traces. Has anyone some idea on what these means? I have attached the stacktrace with this post
View 2 Replies View RelatedI have installed lilypond 2.14.1 on my Fedora 14 machine, as per the lilypond instructions for linux. When I run lilypond, it gives the following error message. /usr/local/lilypond/usr/bin/lilypond: error while loading shared libraries: libgmp.so.3: cannot enable executable stack as shared object requires:Permission denied I see several threads here already about executable stacks. I have already tried execstack to set/clear the flag for that shared object. Neither allows lilypond to run.
View 1 Replies View RelatedI'd like to set the max stack size at boot time, preferably as early as possible. I had thought there's a kernel parameter for this, but I cannot find any reference to one.Adding "ulimit -s" to rc.sysinit was not effective; I've grepped /etc/init.d but it is not used subsequently. So what I currently have is my default runlevel set to 1, with no services except udev-post, then in rc.local:
Code:
ulimit -s 1024
telinit 3
3 being my normal runlevel with all necessary services. However, again that ulimit is being ignored, because after login it is still set to 8192. If after login I manually set the limit and change from 3 to 1 and back again (to restart all services), everything is copacetic.
Does anyone know why ulimit -s is ineffective prior to login or how I can set the max stack size at boot time? I'm just noticing that under "upstart" runlevel services are not controlled by rc.d content. Preuming:
#1 My desire to make F14 work without upstart, using ye olde sysinitv which weren't broke so I don't need it fixed, is going to be like p'sing up a rope.
#2 That systemd is replacing upstart so I might as well try to learn about that.
how can I get "rc.local" functionality under systemd?
I just encountered an odd network stack glitch and wondered if anyone has seen this before, or knows what could cause it. When I connect to services on localhost (127.0.0.1) if there is a process listening, it works OK as expected. there is no process listening, I should get a NAK and see a connection refused message.With this glitch, that was not happening. And this was with 127.0.0.1 to 127.0.0.1. Nothing was listening, but the SYN attempts were all that were happening. If there was something listening that worked OK. Connections to other hosts worked as expected.
View 2 Replies View Relatedwould like to install a Bluetooth and my AT&T 3g fob
View 1 Replies View RelatedI need to call some other functions in "int init_module(void)" and module. So I need a stack. How can I setup a stack (1kB) for my module in C?
View 11 Replies View RelatedWhen I set the stack base address of the child thread using the POSIX library function "pthread_attr_setstackaddr()", I am unable to access the memory contents of its parent. The data-structures that are created on the HEAP of its parent using malloc() are either getting destroyed or unaccessible when moving to the context of the child thread. These data-structures are being passed as an argument to the child thread.Even if I make these variables global then also it is not working.pthread_attr_setstacksize(tattr, ...);stackbase = (void *) malloc(...);pthread_attr_setstackaddr(tattr, stackbase);But when I create the child thread without setting its stack base address using that pthread_attr_setstackaddr(), then it is able to access the parent's memory contents.
View 1 Replies View RelatedIf I issue the following and the process doesn't quit, is there a way to view what it's doing with the SIGTERM signal on the stack? Is this done via the pstack command?kill -s SIGTERM <PID>
View 4 Replies View RelatedWhy is it in Linux that there is a stack size set by default? And why is it so small? (My system is set to 8192 kbytes.) And why is there a default limit on the stack size when the max memory and virtual memory size are, by default, unlimited? (Aren't they both fed from the same place ultimately?)
Reason I ask: I want to use recursive functions in my programming a lot more. Problem is, if the language (or implementation) doesn't happen to support tail-call recursion, then I can be pretty well certain that the first huge problem that gets thrown at my function is going to kill my program because the stack size limit is going to be quickly reached. Obviously, I can change the stack size limit for my own computers, but it doesn't feel so great knowing that most of the people who copy and execute my code will have probably have overlooked this. Anyway, does anyone know: is this small default stack size limit just one of those historical artifacts, or is there some technical reason for it?