Replace gethostbyaddr(3) with getnameinfo(3). Remove the sigprocmask()

that was necessary for gethostbyaddr() because the latter is not
signal safe.  Change the return code semantics of priv_getnameinfo()
to match getnameinfo(3).
input and OK jca@

diff --git a/usr.sbin/syslogd/privsep.c b/usr.sbin/syslogd/privsep.c
index 8144e10..482ced7 100644 (file)
--- a/usr.sbin/syslogd/privsep.c
+++ b/usr.sbin/syslogd/privsep.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: privsep.c,v 1.37 2014/08/20 19:16:27 bluhm Exp $      */
+/*     $OpenBSD: privsep.c,v 1.38 2014/08/20 20:10:17 bluhm Exp $      */
 
 /*
  * Copyright (c) 2003 Anil Madhavapeddy <anil@recoil.org>
@@ -68,7 +68,7 @@ enum cmd_types {
        PRIV_OPEN_CONFIG,       /* open config file for reading only */
        PRIV_CONFIG_MODIFIED,   /* check if config file has been modified */
        PRIV_GETADDRINFO,       /* resolve host/service names */
-       PRIV_GETHOSTBYADDR,     /* resolve numeric address into hostname */
+       PRIV_GETNAMEINFO,       /* resolve numeric address into hostname */
        PRIV_DONE_CONFIG_PARSE  /* signal that the initial config parse is done */
 };
 
@@ -76,7 +76,7 @@ static int priv_fd = -1;
 static volatile pid_t child_pid = -1;
 static char config_file[MAXPATHLEN];
 static struct stat cf_info;
-static int allow_gethostbyaddr = 0;
+static int allow_getnameinfo = 0;
 static volatile sig_atomic_t cur_state = STATE_INIT;
 
 /* Queue for the allowed logfiles */
@@ -100,12 +100,12 @@ static int  may_read(int, void *, size_t);
 int
 priv_init(char *conf, int numeric, int lockfd, int nullfd, char *argv[])
 {
-       int i, fd, socks[2], cmd, addr_len, addr_af, result, restart;
+       int i, fd, socks[2], cmd, addr_len, result, restart;
        size_t path_len, hostname_len, servname_len;
        char path[MAXPATHLEN], hostname[MAXHOSTNAMELEN];
        char servname[MAXHOSTNAMELEN];
+       struct sockaddr_storage addr;
        struct stat cf_stat;
-       struct hostent *hp;
        struct passwd *pw;
        struct addrinfo hints, *res0;
        struct sigaction sa;
@@ -191,11 +191,11 @@ priv_init(char *conf, int numeric, int lockfd, int nullfd, char *argv[])
        if (stat(config_file, &cf_info) < 0)
                err(1, "stat config file failed");
 
-       /* Save whether or not the child can have access to gethostbyaddr(3) */
+       /* Save whether or not the child can have access to getnameinfo(3) */
        if (numeric > 0)
-               allow_gethostbyaddr = 0;
+               allow_getnameinfo = 0;
        else
-               allow_gethostbyaddr = 1;
+               allow_getnameinfo = 1;
 
        TAILQ_INIT(&lognames);
        increase_state(STATE_CONFIG);
@@ -322,24 +322,24 @@ priv_init(char *conf, int numeric, int lockfd, int nullfd, char *argv[])
                        }
                        break;
 
-               case PRIV_GETHOSTBYADDR:
-                       dprintf("[priv]: msg PRIV_GETHOSTBYADDR received\n");
-                       if (!allow_gethostbyaddr)
-                               errx(1, "rejected attempt to gethostbyaddr");
-                       /* Expecting: length, address, address family */
+               case PRIV_GETNAMEINFO:
+                       dprintf("[priv]: msg PRIV_GETNAMEINFO received\n");
+                       if (!allow_getnameinfo)
+                               errx(1, "rejected attempt to getnameinfo");
+                       /* Expecting: length, sockaddr */
                        must_read(socks[0], &addr_len, sizeof(int));
-                       if (addr_len <= 0 || addr_len > sizeof(hostname))
+                       if (addr_len <= 0 || addr_len > sizeof(addr))
                                _exit(1);
-                       must_read(socks[0], hostname, addr_len);
-                       must_read(socks[0], &addr_af, sizeof(int));
-                       hp = gethostbyaddr(hostname, addr_len, addr_af);
-                       if (hp == NULL) {
+                       must_read(socks[0], &addr, addr_len);
+                       if (getnameinfo((struct sockaddr *)&addr, addr_len,
+                           hostname, sizeof(hostname), NULL, 0,
+                           NI_NOFQDN|NI_NAMEREQD|NI_DGRAM) != 0) {
                                addr_len = 0;
                                must_write(socks[0], &addr_len, sizeof(int));
                        } else {
-                               addr_len = strlen(hp->h_name) + 1;
+                               addr_len = strlen(hostname) + 1;
                                must_write(socks[0], &addr_len, sizeof(int));
-                               must_write(socks[0], hp->h_name, addr_len);
+                               must_write(socks[0], hostname, addr_len);
                        }
                        break;
                default:
@@ -656,8 +656,8 @@ priv_config_parse_done(void)
        must_write(priv_fd, &cmd, sizeof(int));
 }
 
-/* Name/service to address translation.  Response is placed into addr, and
- * the length is returned (zero on error) */
+/* Name/service to address translation.  Response is placed into addr.
+ * Return 0 for success or < 0 for error like getaddrinfo(3) */
 int
 priv_getaddrinfo(char *host, char *serv, struct sockaddr *addr,
     size_t addr_len)
@@ -701,36 +701,36 @@ priv_getaddrinfo(char *host, char *serv, struct sockaddr *addr,
        return (0);
 }
 
-/* Reverse address resolution; response is placed into res, and length of
- * response is returned (zero on error) */
+/* Reverse address resolution; response is placed into host.
+ * Return 0 for success or < 0 for error like getnameinfo(3) */
 int
-priv_gethostbyaddr(char *addr, int addr_len, int af, char *res, size_t res_len)
+priv_getnameinfo(struct sockaddr *sa, socklen_t salen, char *host,
+    size_t hostlen)
 {
        int cmd, ret_len;
 
        if (priv_fd < 0)
                errx(1, "%s called from privileged portion", __func__);
 
-       cmd = PRIV_GETHOSTBYADDR;
+       cmd = PRIV_GETNAMEINFO;
        must_write(priv_fd, &cmd, sizeof(int));
-       must_write(priv_fd, &addr_len, sizeof(int));
-       must_write(priv_fd, addr, addr_len);
-       must_write(priv_fd, &af, sizeof(int));
+       must_write(priv_fd, &salen, sizeof(int));
+       must_write(priv_fd, sa, salen);
 
        /* Expect back an integer size, and then a string of that length */
        must_read(priv_fd, &ret_len, sizeof(int));
 
        /* Check there was no error (indicated by a return of 0) */
        if (!ret_len)
-               return 0;
+               return (-1);
 
        /* Check we don't overflow the passed in buffer */
-       if (res_len < ret_len)
+       if (hostlen < ret_len)
                errx(1, "%s: overflow attempt in return", __func__);
 
        /* Read the resolved hostname */
-       must_read(priv_fd, res, ret_len);
-       return ret_len;
+       must_read(priv_fd, host, ret_len);
+       return (0);
 }
 
 /* Pass the signal through to child */

diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c
index 9452ff2..5b6de91 100644 (file)
--- a/usr.sbin/syslogd/syslogd.c
+++ b/usr.sbin/syslogd/syslogd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: syslogd.c,v 1.113 2014/08/20 19:16:27 bluhm Exp $     */
+/*     $OpenBSD: syslogd.c,v 1.114 2014/08/20 20:10:17 bluhm Exp $     */
 
 /*
  * Copyright (c) 1983, 1988, 1993, 1994
@@ -250,7 +250,7 @@ volatile sig_atomic_t WantDie;
 volatile sig_atomic_t DoInit;
 
 struct filed *cfline(char *, char *);
-void    cvthname(struct sockaddr_in *, char *, size_t);
+void   cvthname(struct sockaddr *, char *, size_t);
 int    decode(const char *, const CODE *);
 void   dodie(int);
 void   doinit(int);
@@ -587,7 +587,7 @@ main(int argc, char *argv[])
                            (struct sockaddr *)&frominet, &len);
                        if (i > 0) {
                                line[i] = '\0';
-                               cvthname(&frominet, resolve,
+                               cvthname((struct sockaddr *)&frominet, resolve,
                                    sizeof resolve);
                                dprintf("cvthname res: %s\n", resolve);
                                printline(resolve, line);
@@ -1096,38 +1096,20 @@ reapchild(int signo)
  * Return a printable representation of a host address.
  */
 void
-cvthname(struct sockaddr_in *f, char *result, size_t res_len)
+cvthname(struct sockaddr *f, char *result, size_t res_len)
 {
-       sigset_t omask, nmask;
-       char *p, *ip;
-       int ret_len;
-
-       if (f->sin_family != AF_INET) {
+       if (getnameinfo(f, f->sa_len, result, res_len, NULL, 0,
+           NI_NUMERICHOST|NI_NUMERICSERV|NI_DGRAM) != 0) {
                dprintf("Malformed from address\n");
                strlcpy(result, "???", res_len);
                return;
        }
-
-       ip = inet_ntoa(f->sin_addr);
-       dprintf("cvthname(%s)\n", ip);
-       if (NoDNS) {
-               strlcpy(result, ip, res_len);
+       dprintf("cvthname(%s)\n", result);
+       if (NoDNS)
                return;
-       }
 
-       sigemptyset(&nmask);
-       sigaddset(&nmask, SIGHUP);
-       sigprocmask(SIG_BLOCK, &nmask, &omask);
-
-       ret_len = priv_gethostbyaddr((char *)&f->sin_addr,
-               sizeof(struct in_addr), f->sin_family, result, res_len);
-
-       sigprocmask(SIG_SETMASK, &omask, NULL);
-       if (ret_len == 0) {
-               dprintf("Host name for your address (%s) unknown\n", ip);
-               strlcpy(result, ip, res_len);
-       } else if ((p = strchr(result, '.')) && strcmp(p + 1, LocalDomain) == 0)
-               *p = '\0';
+       if (priv_getnameinfo(f, f->sa_len, result, res_len) != 0)
+               dprintf("Host name for your address (%s) unknown\n", result);
 }
 
 void

diff --git a/usr.sbin/syslogd/syslogd.h b/usr.sbin/syslogd/syslogd.h
index 1c32c9a..e637bc4 100644 (file)
--- a/usr.sbin/syslogd/syslogd.h
+++ b/usr.sbin/syslogd/syslogd.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: syslogd.h,v 1.10 2014/08/20 19:33:43 bluhm Exp $ */
+/*     $OpenBSD: syslogd.h,v 1.11 2014/08/20 20:10:17 bluhm Exp $ */
 
 /*
  * Copyright (c) 2003 Anil Madhavapeddy <anil@recoil.org>
@@ -29,7 +29,7 @@ FILE *priv_open_config(void);
 void  priv_config_parse_done(void);
 int   priv_config_modified(void);
 int   priv_getaddrinfo(char *, char *, struct sockaddr *, size_t);
-int   priv_gethostbyaddr(char *, int, int, char *, size_t);
+int   priv_getnameinfo(struct sockaddr *, socklen_t, char *, size_t);
 
 /* Terminal message */
 char *ttymsg(struct iovec *, int, char *, int);