The Boston Diaries

The ongoing saga of a programmer who doesn't live in Boston, nor does he even like Boston, but yet named his weblog/journal “The Boston Diaries.”

Go figure.

Friday, July 26, 2002

It's open source, so at least I got it working

Yet more exploits against OpenSSH according to Mark so I should upgrade. Thanks to a suggestion from Mark, I was able to get OpenSSH 3.4p1 compiled and running, with privledge separation under Linux 2.0 (technically, 2.0.36 and 2.0.39): 

#ifdef HAVE_MMAP_ANON_SHARED
#  ifdef USE_MMAP_DEV_ZERO
	{
	  int fh;

	  fh = open("/dev/zero",O_RDWR);
	  if (fh == -1)
	  	fatal("mmap(`/dev/zero'): %s",strerror(errno));
	
	  address = mmap(NULL,size,PROT_WRITE|PROT_READ,MAP_PRIVATE,fh,0);
	  if (address == MAP_FAILED)
	  	fatal("mmap(%lu,%d): %s",(u_long)size,fh,strerror(errno));
	}
#  else
 	address = mmap(NULL, size, PROT_WRITE|PROT_READ, MAP_ANON|MAP_SHARED,
 	    -1, 0);
 	if (address == MAP_FAILED)
 		fatal("mmap(%lu): %s", (u_long)size, strerror(errno));
#  endif
#else
 	fatal("%s: UsePrivilegeSeparation=yes and Compression=yes not supported",
 	    __func__);
#endif

modified openssh-3.4p1/monitor_mm.c:87-109

I had to define USE_MMAP_DEV_ZERO and BROKEN_FD_PASSING in openssh-3.4p1/config.h to get this working. But working it is, thankfully.

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