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Hello, i've got a minimal test case with a C program with the following code Code: #include <stdio.h> int main(){ printf("uid = %d", getuid()); printf("euid = %d", geteuid()); } After ...
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  1. #1
    Just Joined!
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    Dec 2009
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    Running programs under root with suid bit


    Hello,

    i've got a minimal test case with a C program with the following code

    Code:
    #include <stdio.h>
    
    int main(){
    printf("uid = %d", getuid());
    printf("euid = %d", geteuid());
    }
    After compiling the program and running it i get my own user id (1000), so thats fine.

    Then i want to run it under root.

    I do chown root.root <program name> and chmod 4771 <program name>

    after running it again it still shows me 1000 as it's uid.

    Trying stuff like loading modules also does not work, so it really does not have root.

    Am i missing something here?

    Any help would be greatly appreciated.

    Ps.

    I'm running debian lenny, executing the exact same commands on the ping executable does give me the correct results...

  2. #2
    Linux Guru Rubberman's Avatar
    Join Date
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    I can be found either 40 miles west of Chicago, in Chicago, or in a galaxy far, far away.
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    Well, you have remove read permission from "others" (including yourself) which is one thing, and you haven't properly set the setuid bit(s).

    First, set the proper permissions: chmod 755 cmdname
    Then, set the setuid bit(s): chmod +s cmdname

    Try that and see what happens.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

  3. #3
    Just Joined!
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    Dec 2009
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    7
    Hello,

    Thank you for your reply,

    Sorry i have not been able to reply earlier, i've found the solution the partition was mounted with the nosuid flag, which makes using the suid bit kind of hard

    Richard

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