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Questions tagged [setuid]

`setuid` is a file permission flag under Unix-like systems that will run an executable with the file owner's permissions rather than the invoking user's. On some systems (FreeBSD), it further works identically to the related `setgid` flag on directories, causing new files to inherit the directory's permissions rather than the current user's.

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Run child processes as different user from a long running Python process

I've got a long running, daemonized Python process that uses subprocess to spawn new child processes when certain events occur. The long running process is started by a user with super user privileges. I need the child processes it spawns to run as…
Peter Parente
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RealUID, Saved UID, Effective UID. What's going on?

This is a set-root-uid program $ls -l -rwsr-sr-x 1 root root 7406 2011-12-13 22:37 ./x* The source code: int main(void) { printf( " UID GID \n" "Real %d Real %d \n" "Effective %d Effective…
Lelouch Lamperouge
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Calling a script from a setuid root C program - script does not run as root

I need to run a bash script as root (passwordless sudo or su not viable) and since you cannot setuid a script in Linux, I thought about calling it from an executable and making it setuid: $ cat wrapper.c int main(void) { system("/bin/bash…
Jack
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Getting message "sudo: must be setuid root", but sudo IS already owned by root

I'm trying to run sudo, and it's failing: gregd@david $ sudo ls sudo: must be setuid root gregd@david $ which sudo /usr/bin/sudo gregd@david $ ll /usr/bin/sudo -rwxr-xr-x 1 root root 165K 2012-05-16 00:25 /usr/bin/sudo* Any suggestions on how to…
Greg Dougherty
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Using $ORIGIN with setuid application does not fail as expected

I have a librandom.so library and a main exectuable which was compiled as follows: $ clang++ -o main main.o -lrandom -L. -Wl,-rpath,"\$ORIGIN" They are both in the same directory. Since main has $ORIGIN in its rpath, it works fine - ./main returns…
Amir Rachum
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system() vs execve()

Both system() and execve() can be used to execute another command inside a program. Why in set-UID programs, system() is dangerous, while execve() is safe ?
Jake
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Setuid bit on python script : Linux vs Solaris

I am running this small python script on both linux and Solaris as a not privileged user : #!/usr/bin/python import os print 'uid,euid =',os.getuid(),os.geteuid() Before running, the setuid bit is set on the script (not on python interpreter)…
Eric
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Linux C programming execute as user

I have an program which I run as root. I would like the program to execute another application as a normal user. I tried setgid() and it works, but I can't then go back to root or another user. The program for the time being is very simple; …
Dominik Brzeziński
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how do i run valgrind to a process which has super user bit on?

I am running valgrind as follows:- /usr/local/bin/valgrind "process_name" After excecution its giving me following error ==21731== ==21731== Warning: Can't execute setuid/setgid executable: ==21731== Possible workaround: remove…
anish
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What does connecting to own network daemon mean?

i'm currently doing the bandit wargames from overthewire.org (for those of you who don't know it's a website with different tasks that you get to do in order to improve your hacking skills). i did them before but i got stuck pretty early and i…
jumpindonuts
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setuid vs seteuid function

What is the difference between setuid and seteuid function. In man page both of the function have similar description. setuid: DESCRIPTION setuid() sets the effective user ID of the calling process. If the effective UID of the caller is…
mohangraj
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Why do I need setuid(0) within a setuid-root C program that calls an administrative program with system()?

I had to do a dirty Linux hack for somebody so they could start a printer with the cupsenable printername shell command while being a non-root user. I didn't want them to be able to use the entirety of the cupsenable syntax as root, so I just wrote…
JCCyC
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LD_PRELOAD with setuid binary

I am trying to use LD_PRELOAD to preload a library with an application that has setuid permissions. Tried LD_PRELOAD at first, and it seemed like it was being ignored with the setuid binary, though it was working when I tried it with others like ls,…
Mark Lobo
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How to use setuid() from root to become user, with the possibility of becoming root again later?

I'm trying to do the safe thing, and have a program that needs to runs as root to drop its privileges when it doesn't need them. This works well if I chmod my binary with the SUID bit, and make it belong to root, as now I have UID = some user, and…
Florian
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Git post-receive hook to update a local clone owned by a different user

I'm trying to set up a git post-receive hook such that when a commit is received, another clone of the repository on the machine gets updated (i.e. does a git pull origin master). I'm using gitosis to serve the repository and as such I believe a…
Ibrahim
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