Date: Wed, 28 Jan 2015 20:06:15 -0700 From: jd1008 <jd1008@gmail.com> To: freebsd-questions@freebsd.org Subject: Re: Linux "Ghost" Remote Code Execution Vulnerability Message-ID: <54C9A3A7.5080202@gmail.com> In-Reply-To: <20150129033838.810254de.freebsd@edvax.de> References: <20150128145247.5086e9a4@scorpio> <20150129033838.810254de.freebsd@edvax.de>
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On 01/28/2015 07:38 PM, Polytropon wrote: > On Wed, 28 Jan 2015 14:52:47 -0500, Jerry wrote: >> Does this vulnerability affect FreeBSD? >> >> https://www.us-cert.gov/ncas/current-activity/2015/01/27/Linux-Ghost-Remote-Code-Execution-Vulnerability > FreeBSD's gethostbyname() is located in the standard C library, > which is libc, not glibc (that Linux is using), so probably > FreeBSD is not affected. However, programs linked against > glibc and run in the Linux ABI environment might be affected, > I assume. > > You can find a demonstration program here: > > http://www.openwall.com/lists/oss-security/2015/01/27/9 > > It's in section 4. > > On my home system, I get this: > > % cc -Wall -o ghost ghost.c > % ./ghost > should not happen > > Surprise: Neither "vulnerable" nor "not vulnerable" is printed. > That result is interesting. It might indicate ternary logic. > YES, NO, FILE_NOT_FOUND. :-) > > Note that 4.1 explicitely talks about "The GNU C Library" > which FreeBSD does not use (or have). Section 4 mentions > other programs (such as mount.nfs, ping, procmail) for > further explanation. Then you do not have the real mccoy. This is the real Mccoy: /* ghosttest.c: GHOST vulnerability tester */ /* Credit: http://www.openwall.com/lists/oss-security/2015/01/27/9 */ #include <netdb.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <errno.h> #define CANARY "in_the_coal_mine" struct { char buffer[1024]; char canary[sizeof(CANARY)]; } temp = { "buffer", CANARY }; int main(void) { struct hostent resbuf; struct hostent *result; int herrno; int retval; /*** strlen (name) = size_needed - sizeof (*host_addr) - sizeof (*h_addr_ptrs) - 1; ***/ size_t len = sizeof(temp.buffer) - 16*sizeof(unsigned char) - 2*sizeof(char *) - 1; char name[sizeof(temp.buffer)]; memset(name, '0', len); name[len] = '\0'; retval = gethostbyname_r(name, &resbuf, temp.buffer, sizeof(temp.buffer), &result, &herrno); if (strcmp(temp.canary, CANARY) != 0) { puts("vulnerable"); exit(EXIT_SUCCESS); } if (retval == ERANGE) { puts("not vulnerable"); exit(EXIT_SUCCESS); } puts("should not happen"); exit(EXIT_FAILURE); }
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