On Mon, Jun 14, 2021 at 6:55 PM youling 257 youling257@gmail.com wrote:
if try to find problem on userspace, i used linux 5.13rc6 on old android 7 cm14.1, not aosp android 11. http://git.osdn.net/view?p=android-x86/system-core.git%3Ba=blob%3Bf=init/ser...
457 if (!seclabel_.empty()) { 458 if (setexeccon(seclabel_.c_str()) < 0) { 459 ERROR("cannot setexeccon('%s'): %s\n", 460 seclabel_.c_str(), strerror(errno)); 461 _exit(127); 462 } 463 }
I have no idea where the cm14.1 libraries are. Does anybody know where the matching source code for setexeccon() would be?
For me - obviously not on cm14.1 - all "setexeccon()" does is
n = openat(AT_FDCWD, "/proc/thread-self/attr/exec", O_RDWR|O_CLOEXEC) write(n, string, len) close(n)
and if that fails, it would seem to indicate that proc_mem_open() failed. Which would be mm_access() failing. But I don't see how that can be the case, because mm_access() explicitly allows "mm == current->mm" (which the above clearly should be).
youling, can you double-check with the current -git tree? But as far as I can tell, my minimal patch is exactly the same as Kees' patch (just smaller and simpler).
Kees, do you see anything?
Linus