Questions tagged [setgid]

setgid is a bit that can be set in the filesystem. If an executable is setgid, then when that executable is run, the spawned process will have an effective group id (EGID) of the group owning the executable, instead of the group of the user running it.

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Why I can't set the setuid for "others"?

I can't set other's setuid bit. Why? Is there some security lock? $ ls -l -rwxrwxr-x 1 allexj allexj 16784 Mar 11 17:30 a....
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Why "permission denied" when running `less` with chmod 6110?

Assume you are user x, so running id gives uid=1001(x) gid=1001(x) groups=1001(x) And there is also a user y with uid=1002(y) gid=1002(y) groups=1002(y) Now as root we create a file readme in user's ...
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Using umask vs. setgid: best practice for peacefully sharing a directory in a Linux users group?

What is the best way to share a directory between multiple Linux users? Say I have a directory at /foo (a regular directory no NFS or else) and a bunch of users added to the group bar. What I want is ...
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rsync not setting stickybit / GID bit

Using the following rsync command, the RWX permissions are being correctly set for both files and directories but the sticky bit options are not. rsync -rtvz --partial-dir=.rsync-partial --chmod=Da+t,...
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How to access/set other user's environment variables after setregid() and setreuid() in C

I have a privileged C program that is executed by a standard user (say stduser) and on execution switches to a system user (say sysuser) as follows. Basically, I am trying to do something similar to ...
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setgid being ignored by application

I run a Weblogic installation on a Oracle Linux Server 7.8. An application in weblogic will write some files to a local directory as output. The application uses the Oracle Weblogic FileAdapter for it....
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stickybits setgid not working

I have structure like: /home/reed/, user=reed, group=reed - apache-conf, user=reed, group=reed - apache-web, user=reed, group=apache, perm=0770 - www.website.com, user=reed, group=apache, ...
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How to set different file and directory default permissions with or without ACL within a shared directory with `setgid` and `sticky bit` set?

I have searched over on multiple SE sites, though there doesn't seem to be an answer to this question. Using setgid bit, it allows to retain parent group and sticky bit for ownership, though this ...
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Setgid strange behavior

I have following files: ----rw---- 1 wojtek users 4 Oct 26 15:56 data.txt -rwx--s--x 1 wojtek users 8864 Oct 26 16:00 fopen_setgid When I run fopen_setgid as daro then everything works as ...
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How to remove a setgid directory that links to another location?

I use an environment variable $DATAPATH that conveniently takes me to where I store my data. Idk what I did just now but I created a folder in my home directory called '$DATAPATH', and when I cd into ...
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Applying special permission suid & sgid

I was in the processs of learning a bit about the special permission in Linux. Where is find certain anomilies. suid - For executable/files where user subsume the UID/permission of the owner. With ...
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Why is chmod g+s on a directory being ignored?

I have a git (actually git-annex) repository I'm trying to make shared, part of which involves setting the set-group-id bit on several directories. This is on a Debian GNU/Linux Stretch box, on an ...
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4 votes
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setgid: chmod g+s,g-x on executable

I'm not understanding setgid on executables on my platform (ubuntu). g-x,g+s is not giving the process effective group permissions of the program's owner. $ gcc perms.c -o perms; ls -l ; ./perms -...
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Can't set group ID bit on directory

I have created a directory called newDir and changed the group it belongs to with mkdir newDir && chgrp test-group newDir. I was user me when I did this. Calling stat newDir produces ...
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Samba shared folder with setgid problem

I am setting up a file server with a shared directory. Inside, there are per-user folders that are readable by any user and a shared directory that is readable and writeable by any user. The per-...
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Linux open() syscall and folder permissions

I have a process P which is spawned by a process owned by root. After P is created setguid() and setuid() are called and it runs as user U. The process P attempts to create a file f on a folder F (in ...
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7 votes
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Unset setgid bit with chmod numeric mode

I've just noticed some interesting behavior with chmod when unsetting the setgid bit: $ mkdir test $ chmod 2755 test $ stat -c '%a %n' test 2755 test # as expected $ chmod 0755 test $ stat -c '%a %n'...
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SETUID and SETGID Behavior

The setup: ~$ ls -l /etc/sudoers -r--r----- 1 root root 614 2017-09-10 20:29 /etc/sudoers ~$ ls -l /etc/shadow -rw-r----- 1 root shadow 794 2011-04-18 11:49 /etc/shadow $ ls -l $(which ht) -rwsr-sr-...
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How to call chmod and preserve the SGID bit?

I have the following directory structure: + public/ |-+ pics/ | |-- a | `-- b `-+ thumbs/ |-- a `-- b I would like all the files in the tree to be owned by gallery:http with ug=rwX,o= mode set. ...
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How to set setgid bit for a program to allow it change its group folder?

The preconditions are somewhat complex, so here is the context: There is a program, that is launched through a shell script; The shell script launches the program through a .jar file; I want this ...
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4 votes
2 answers
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Meaning of setgid on an executable

I get that setuid on a binary executable allows the process to get the effective uid of the binary owner. What I cannot understand is what if setuid bit is off but setgid bit is on for a particular ...
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Do I need to set uid bit in this case?

I have modified xlockmore source to add a feature I needed, but it is unable to read the shadow password file and is asking me to set uid or gid bit on the binary. But the official binary I use doesn'...
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setgid sticky bit not working

I have yet another frustrating problem. I have a group of users belonging to the "testing" group. I have a folder located at /var/log/projects with the setgid bit set. This is so any new files or ...
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scp file to remote server prevent delete

A team want to implement a crude file dump backup solution to be used by multiple hosts. They have a remote user on the backup server backupusr that they can SSH/SCP with, with SSH keys setup. The ...
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2 votes
1 answer
886 views

Share files/directories by setgid

To allow write access to a specific group, shared files/folders can be made writeable by default for everyone in this group and the owning group can be automatically fixed to the group which owns the ...
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79 votes
5 answers
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'chmod g+s' command

Hello I want to understand the role of the chmod g+s command in Unix. I also would like to know what it does in this particular context: cd /home/canard; touch un; chgrp canard .; chmod g+s .; touch ...
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Why the S_ISUID and S_ISGID mode bits got cleared when the owner or group of an executable file are changed by an unprivileged user

I was reading the man page of chown. I don't understand why S_ISUID and S_ISGID mode should be cleared when the function returns successfully.
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5 votes
2 answers
1k views

Why ssh-agent group ownership is not root

Trying to understand why ssh-agent has sgid bit and found this post ssh-agent has sgid I have another question, why the group ownership of ssh-agent is nobody not root? What is the reason behind it? ...
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Limit program execution to a list of arguments

I would like that my Unix users can only run a specific command insecurecommand with a controlled list of arguments stored in a file. The only solution I have found at this time is to : Create a new ...
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11 votes
2 answers
5k views

Group memberships and setuid/setgid processes

Processes which de-escalate privileges via setuid() and setgid() do not seem to inherit the group memberships of the uid/gid they set. I have a server process that must be executed as root in order ...
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3 votes
1 answer
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setgid binary doesn't have permission, mount's right, I'm missing something, but what, please?

I've checked the manpages, the mount, the permissions ... (edit: combined history into one sequence as requested. Starting to seem a not-simple problem. Nothing new since last edit, just bundled up ...
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