$NetBSD: patch-aa,v 1.5 2011/03/18 15:26:30 gdt Exp $ This patch has hunks for multiple reasons: 1) Ancient fix to avoid going beyond s2. 2) Added CVE-2010-1132 patch from: https://bugzilla.redhat.com/attachment.cgi?id=401011 3) (Most of, some in .h) patch to add option to not scan mail from authenticated users, from: http://lists.freebsd.org/pipermail/freebsd-ports-bugs/2006-November/106024.html 4) Avoid memory allocation in after fork and before exec. From PR pkg/44704. --- spamass-milter.cpp.orig 2011-03-18 15:15:56.000000000 +0000 +++ spamass-milter.cpp @@ -170,10 +170,7 @@ char *spambucket; bool flag_full_email = false; /* pass full email address to spamc */ bool flag_expand = false; /* alias/virtusertable expansion */ bool warnedmacro = false; /* have we logged that we couldn't fetch a macro? */ - -#if defined(__FreeBSD__) /* popen bug - see PR bin/50770 */ -static pthread_mutex_t popen_mutex = PTHREAD_MUTEX_INITIALIZER; -#endif +bool auth = false; /* don't scan authenticated users */ // {{{ main() @@ -181,7 +178,7 @@ int main(int argc, char* argv[]) { int c, err = 0; - const char *args = "fd:mMp:P:r:u:D:i:b:B:e:x"; + const char *args = "fd:mMp:P:r:u:D:i:b:B:e:xa"; char *sock = NULL; bool dofork = false; char *pidfilename = NULL; @@ -196,6 +193,9 @@ main(int argc, char* argv[]) /* Process command line options */ while ((c = getopt(argc, argv, args)) != -1) { switch (c) { + case 'a': + auth = true; + break; case 'f': dofork = true; break; @@ -281,7 +281,7 @@ main(int argc, char* argv[]) cout << "SpamAssassin Sendmail Milter Plugin" << endl; cout << "Usage: spamass-milter -p socket [-b|-B bucket] [-d xx[,yy...]] [-D host]" << endl; cout << " [-e defaultdomain] [-f] [-i networks] [-m] [-M]" << endl; - cout << " [-P pidfile] [-r nn] [-u defaultuser] [-x]" << endl; + cout << " [-P pidfile] [-r nn] [-u defaultuser] [-x] [-a]" << endl; cout << " [-- spamc args ]" << endl; cout << " -p socket: path to create socket" << endl; cout << " -b bucket: redirect spam to this mail address. The orignal" << endl; @@ -302,6 +302,7 @@ main(int argc, char* argv[]) cout << " -u defaultuser: pass the recipient's username to spamc.\n" " Uses 'defaultuser' if there are multiple recipients." << endl; cout << " -x: pass email address through alias and virtusertable expansion." << endl; + cout << " -a: don't scan messages over an authenticated connection." << endl; cout << " -- spamc args: pass the remaining flags to spamc." << endl; exit(EX_USAGE); @@ -461,59 +462,24 @@ assassinate(SMFICTX* ctx, SpamAssassin* send another copy. The milter API will not let you send the message AND return a failure code to the sender, so this is the only way to do it. */ -#if defined(__FreeBSD__) - int rv; -#endif - -#if defined(HAVE_ASPRINTF) - char *buf; -#else - char buf[1024]; -#endif - char *fmt="%s \"%s\""; + char *popen_argv[3]; FILE *p; -#if defined(HAVE_ASPRINTF) - asprintf(&buf, fmt, SENDMAIL, spambucket); -#else -#if defined(HAVE_SNPRINTF) - snprintf(buf, sizeof(buf)-1, fmt, SENDMAIL, spambucket); -#else - /* XXX possible buffer overflow here */ - sprintf(buf, fmt, SENDMAIL, spambucket); -#endif -#endif - - debug(D_COPY, "calling %s", buf); -#if defined(__FreeBSD__) /* popen bug - see PR bin/50770 */ - rv = pthread_mutex_lock(&popen_mutex); - if (rv) - { - debug(D_ALWAYS, "Could not lock popen mutex: %s", strerror(rv)); - abort(); - } -#endif - p = popen(buf, "w"); + popen_argv[0] = SENDMAIL; + popen_argv[1] = spambucket; + popen_argv[2] = NULL; + + debug(D_COPY, "calling %s %s", SENDMAIL, spambucket); + p = popenv(popen_argv, "w"); if (!p) { - debug(D_COPY, "popen failed(%s). Will not send a copy to spambucket", strerror(errno)); + debug(D_COPY, "popenv failed(%s). Will not send a copy to spambucket", strerror(errno)); } else { // Send message provided by SpamAssassin fwrite(assassin->d().c_str(), assassin->d().size(), 1, p); - pclose(p); p = NULL; + fclose(p); p = NULL; } -#if defined(__FreeBSD__) - rv = pthread_mutex_unlock(&popen_mutex); - if (rv) - { - debug(D_ALWAYS, "Could not unlock popen mutex: %s", strerror(rv)); - abort(); - } -#endif -#if defined(HAVE_ASPRINTF) - free(buf); -#endif } return SMFIS_REJECT; } @@ -783,6 +749,15 @@ mlfi_envfrom(SMFICTX* ctx, char** envfro } /* debug(D_ALWAYS, "ZZZ got private context %p", sctx); */ + if (auth) { + const char *auth_type = smfi_getsymval(ctx, "{auth_type}"); + + if (auth_type) { + debug(D_MISC, "auth_type=%s", auth_type); + return SMFIS_ACCEPT; + } + } + debug(D_FUNC, "mlfi_envfrom: enter"); try { // launch new SpamAssassin @@ -842,30 +817,19 @@ mlfi_envrcpt(SMFICTX* ctx, char** envrcp /* open a pipe to sendmail so we can do address expansion */ char buf[1024]; - char *fmt="%s -bv \"%s\" 2>&1"; - -#if defined(HAVE_SNPRINTF) - snprintf(buf, sizeof(buf)-1, fmt, SENDMAIL, envrcpt[0]); -#else - /* XXX possible buffer overflow here */ - sprintf(buf, fmt, SENDMAIL, envrcpt[0]); -#endif + char *popen_argv[4]; + + popen_argv[0] = SENDMAIL; + popen_argv[1] = "-bv"; + popen_argv[2] = envrcpt[0]; + popen_argv[3] = NULL; - debug(D_RCPT, "calling %s", buf); + debug(D_RCPT, "calling %s -bv %s", SENDMAIL, envrcpt[0]); -#if defined(__FreeBSD__) /* popen bug - see PR bin/50770 */ - rv = pthread_mutex_lock(&popen_mutex); - if (rv) - { - debug(D_ALWAYS, "Could not lock popen mutex: %s", strerror(rv)); - abort(); - } -#endif - - p = popen(buf, "r"); + p = popenv(popen_argv, "r"); if (!p) { - debug(D_RCPT, "popen failed(%s). Will not expand aliases", strerror(errno)); + debug(D_RCPT, "popenv failed(%s). Will not expand aliases", strerror(errno)); assassin->expandedrcpt.push_back(envrcpt[0]); } else { @@ -890,16 +854,8 @@ mlfi_envrcpt(SMFICTX* ctx, char** envrcp assassin->expandedrcpt.push_back(p+7); } } - pclose(p); p = NULL; + fclose(p); p = NULL; } -#if defined(__FreeBSD__) - rv = pthread_mutex_unlock(&popen_mutex); - if (rv) - { - debug(D_ALWAYS, "Could not unlock popen mutex: %s", strerror(rv)); - abort(); - } -#endif } else { assassin->expandedrcpt.push_back(envrcpt[0]); @@ -1343,6 +1299,22 @@ SpamAssassin::~SpamAssassin() void SpamAssassin::Connect() { + int argc; + char *argv[100]; + char spamc_user[64]; + + if (expandedrcpt.size() != 1) { + debug(D_RCPT, "%d recipients; spamc gets default username %s", (int)expandedrcpt.size(), defaultuser); + strlcpy(spamc_user, defaultuser, sizeof(spamc_user)); + } else { + if (flag_full_email) + strlcpy(spamc_user, full_user().c_str(), sizeof(spamc_user)); + else + strlcpy(spamc_user, local_user().c_str(), sizeof(spamc_user)); + strlwr(spamc_user); + debug(D_RCPT, "spamc gets %s", spamc_user); + } + // set up pipes for in- and output if (pipe(pipe_io[0])) throw string(string("pipe error: ")+string(strerror(errno))); @@ -1376,33 +1348,12 @@ void SpamAssassin::Connect() // absolute path (determined in autoconf) // should be a little more secure // XXX arbitrary 100-argument max - int argc = 0; - char** argv = (char**) malloc(100*sizeof(char*)); + argc = 0; argv[argc++] = SPAMC; if (flag_sniffuser) { argv[argc++] = "-u"; - if ( expandedrcpt.size() != 1 ) - { - // More (or less?) than one recipient, so we pass the default - // username to SPAMC. This way special rules can be defined for - // multi recipient messages. - debug(D_RCPT, "%d recipients; spamc gets default username %s", (int)expandedrcpt.size(), defaultuser); - argv[argc++] = defaultuser; - } else - { - // There is only 1 recipient so we pass the username - // (converted to lowercase) to SPAMC. Don't worry about - // freeing this memory as we're exec()ing anyhow. - if (flag_full_email) - argv[argc] = strlwr(strdup(full_user().c_str())); - else - argv[argc] = strlwr(strdup(local_user().c_str())); - - debug(D_RCPT, "spamc gets %s", argv[argc]); - - argc++; - } + argv[argc++] = spamc_user; } if (spamdhost) { @@ -2033,7 +1984,7 @@ cmp_nocase_partial(const string& s, cons string::const_iterator p=s.begin(); string::const_iterator p2=s2.begin(); - while ( p != s.end() && p2 <= s2.end() ) { + while ( p != s.end() ) { if (toupper(*p) != toupper(*p2)) { debug(D_STR, "c_nc_p: <%s><%s> : miss", s.c_str(), s2.c_str()); @@ -2157,5 +2108,71 @@ void warnmacro(char *macro, char *scope) warnedmacro = true; } +/* + untrusted-argument-safe popen function - only supports "r" and "w" modes + for simplicity, and always reads stdout and stderr in "r" mode. Call + fclose to close the FILE. +*/ +FILE *popenv(char *const argv[], const char *type) +{ + FILE *iop; + int pdes[2]; + int save_errno; + if ((*type != 'r' && *type != 'w') || type[1]) + { + errno = EINVAL; + return (NULL); + } + if (pipe(pdes) < 0) + return (NULL); + switch (fork()) { + + case -1: /* Error. */ + save_errno = errno; + (void)close(pdes[0]); + (void)close(pdes[1]); + errno = save_errno; + return (NULL); + /* NOTREACHED */ + case 0: /* Child. */ + if (*type == 'r') { + /* + * The dup2() to STDIN_FILENO is repeated to avoid + * writing to pdes[1], which might corrupt the + * parent's copy. This isn't good enough in + * general, since the exit() is no return, so + * the compiler is free to corrupt all the local + * variables. + */ + (void)close(pdes[0]); + (void)dup2(pdes[1], STDOUT_FILENO); + (void)dup2(pdes[1], STDERR_FILENO); + if (pdes[1] != STDOUT_FILENO && pdes[1] != STDERR_FILENO) { + (void)close(pdes[1]); + } + } else { + if (pdes[0] != STDIN_FILENO) { + (void)dup2(pdes[0], STDIN_FILENO); + (void)close(pdes[0]); + } + (void)close(pdes[1]); + } + execv(argv[0], argv); + exit(127); + /* NOTREACHED */ + } + + /* Parent; assume fdopen can't fail. */ + if (*type == 'r') { + iop = fdopen(pdes[0], type); + (void)close(pdes[1]); + } else { + iop = fdopen(pdes[1], type); + (void)close(pdes[0]); + } + + return (iop); +} + // }}} // vim6:ai:noexpandtab