execl() fails with EACCES after setuid() call
 

Hello there,

myname is Matteo and I'm writing from Italy.

Maybe this is a very trivial issue but I'm going crazy on it.

I have a simple application, say test, owned by myuid.mygid, of course different from root, where myuid=31 mygid=31.

Inside it I just do:

...

res = setgid(31);
if (res != 0)
printf("setgid() failed\n");

res = setuid(31);
if (res != 0)
printf("setuid() failed\n");

res = execl("/usr/sbin/myapp", (char*) NULL);
printf("execl() returned %d\n", res);
if (res != 0)
printf("execl() error: %s (%d)\n", strerror(errno), errno);

...

Please note that myapp is owned by 0.mygid and is readable/executable by mygid and the same for /usr and /usr/sbin.

But execl() fails with EACCES.

It seems that setuid() is the real cause, because if I comment only it the result is OK.

Can anyone please tell me what's wrong?

Many many thanks,

Matteo.

This seems to be a duplicate question. I've posted a response on the other copy of this question.

I'm closing this thread, as it's a duplicate.