Switch user ID/root directory with -Z before opening savefiles for output.

[tcpdump] / tcpdump.c

diff --git a/tcpdump.c b/tcpdump.c
index da88d3837120501d8284ed2b1b446dddcc1ef93a..c8da36baa92592284844e58af56b537a647b3f55 100644 (file)
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -92,6 +92,9 @@ netdissect_options *gndo = &Gndo;
 
 static int dflag;                      /* print filter code */
 static int Lflag;                      /* list available data link types and exit */
 
 static int dflag;                      /* print filter code */
 static int Lflag;                      /* list available data link types and exit */

+#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
+static int Jflag;                      /* list available time stamp types */
+#endif

 static char *zflag = NULL;             /* compress each savefile using a specified command (like gzip or bzip2) */
 
 static int infodelay;
 static char *zflag = NULL;             /* compress each savefile using a specified command (like gzip or bzip2) */
 
 static int infodelay;


@@ -151,7 +154,6 @@ static struct printer printers[] = {
 #ifdef DLT_ARCNET_LINUX
        { arcnet_linux_if_print, DLT_ARCNET_LINUX },
 #endif
 #ifdef DLT_ARCNET_LINUX
        { arcnet_linux_if_print, DLT_ARCNET_LINUX },
 #endif

-       { ether_if_print,       DLT_EN10MB },

        { token_if_print,       DLT_IEEE802 },
 #ifdef DLT_LANE8023
        { lane_if_print,        DLT_LANE8023 },
        { token_if_print,       DLT_IEEE802 },
 #ifdef DLT_LANE8023
        { lane_if_print,        DLT_LANE8023 },


@@ -303,11 +305,15 @@ static struct printer printers[] = {
 };
 
 static struct ndo_printer ndo_printers[] = {
 };
 
 static struct ndo_printer ndo_printers[] = {

+       { ether_if_print,       DLT_EN10MB },

 #ifdef DLT_IPNET
        { ipnet_if_print,       DLT_IPNET },
 #endif
 #ifdef DLT_IEEE802_15_4
        { ieee802_15_4_if_print, DLT_IEEE802_15_4 },
 #ifdef DLT_IPNET
        { ipnet_if_print,       DLT_IPNET },
 #endif
 #ifdef DLT_IEEE802_15_4
        { ieee802_15_4_if_print, DLT_IEEE802_15_4 },

+#endif
+#ifdef DLT_IEEE802_15_4_NOFCS
+       { ieee802_15_4_if_print, DLT_IEEE802_15_4_NOFCS },

 #endif
        { NULL,                 0 },
 };
 #endif
        { NULL,                 0 },
 };


@@ -362,6 +368,40 @@ struct dump_info {
        pcap_dumper_t *p;
 };
 
        pcap_dumper_t *p;
 };
 

+#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
+static void
+show_tstamp_types_and_exit(const char *device, pcap_t *pd)
+{
+       int n_tstamp_types;
+       int *tstamp_types = 0;
+       const char *tstamp_type_name;
+       int i;
+
+       n_tstamp_types = pcap_list_tstamp_types(pd, &tstamp_types);
+       if (n_tstamp_types < 0)
+               error("%s", pcap_geterr(pd));
+
+       if (n_tstamp_types == 0) {
+               fprintf(stderr, "Time stamp type cannot be set for %s\n",
+                   device);
+               exit(0);
+       }
+       fprintf(stderr, "Time stamp types for %s (use option -j to set):\n",
+           device);
+       for (i = 0; i < n_tstamp_types; i++) {
+               tstamp_type_name = pcap_tstamp_type_val_to_name(tstamp_types[i]);
+               if (tstamp_type_name != NULL) {
+                       (void) fprintf(stderr, "  %s (%s)\n", tstamp_type_name,
+                           pcap_tstamp_type_val_to_description(tstamp_types[i]));
+               } else {
+                       (void) fprintf(stderr, "  %d\n", tstamp_types[i]);
+               }
+       }
+       pcap_free_tstamp_types(tstamp_types);
+       exit(0);
+}
+#endif
+

 static void
 show_dlts_and_exit(const char *device, pcap_t *pd)
 {
 static void
 show_dlts_and_exit(const char *device, pcap_t *pd)
 {


@@ -403,13 +443,13 @@ show_dlts_and_exit(const char *device, pcap_t *pd)
                        if (lookup_printer(dlts[n_dlts]) == NULL
                             && lookup_ndo_printer(dlts[n_dlts]) == NULL)
                                (void) fprintf(stderr, " (printing not supported)");
                        if (lookup_printer(dlts[n_dlts]) == NULL
                             && lookup_ndo_printer(dlts[n_dlts]) == NULL)
                                (void) fprintf(stderr, " (printing not supported)");

-                       putchar('\n');
+                       fprintf(stderr, "\n");

                } else {
                        (void) fprintf(stderr, "  DLT %d (printing not supported)\n",
                            dlts[n_dlts]);
                }
        }
                } else {
                        (void) fprintf(stderr, "  DLT %d (printing not supported)\n",
                            dlts[n_dlts]);
                }
        }

-       free(dlts);
+       pcap_free_datalinks(dlts);

        exit(0);
 }
 
        exit(0);
 }
 


@@ -431,6 +471,16 @@ show_dlts_and_exit(const char *device, pcap_t *pd)
 #define I_FLAG
 #endif /* HAVE_PCAP_CREATE */
 
 #define I_FLAG
 #endif /* HAVE_PCAP_CREATE */
 

+#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
+#define j_FLAG         "j:"
+#define j_FLAG_USAGE   " [ -j tstamptype ]"
+#define J_FLAG         "J"
+#else /* PCAP_ERROR_TSTAMP_TYPE_NOTSUP */
+#define j_FLAG
+#define j_FLAG_USAGE
+#define J_FLAG
+#endif /* PCAP_ERROR_TSTAMP_TYPE_NOTSUP */
+

 #ifdef HAVE_PCAP_FINDALLDEVS
 #ifndef HAVE_PCAP_IF_T
 #undef HAVE_PCAP_FINDALLDEVS
 #ifdef HAVE_PCAP_FINDALLDEVS
 #ifndef HAVE_PCAP_IF_T
 #undef HAVE_PCAP_FINDALLDEVS


@@ -575,6 +625,7 @@ main(int argc, char **argv)
        if(wsockinit() != 0) return 1;
 #endif /* WIN32 */
 
        if(wsockinit() != 0) return 1;
 #endif /* WIN32 */
 

+       jflag=-1;       /* not set */

         gndo->ndo_Oflag=1;
        gndo->ndo_Rflag=1;
        gndo->ndo_dlt=-1;
         gndo->ndo_Oflag=1;
        gndo->ndo_Rflag=1;
        gndo->ndo_dlt=-1;


@@ -603,7 +654,7 @@ main(int argc, char **argv)
 
        opterr = 0;
        while (
 
        opterr = 0;
        while (

-           (op = getopt(argc, argv, "aAb" B_FLAG "c:C:d" D_FLAG "eE:fF:G:i:" I_FLAG "KlLm:M:nNOpqr:Rs:StT:u" U_FLAG "vw:W:xXy:Yz:Z:")) != -1)
+           (op = getopt(argc, argv, "aAb" B_FLAG "c:C:d" D_FLAG "eE:fF:G:hi:" I_FLAG j_FLAG J_FLAG "KlLm:M:nNOpqr:Rs:StT:u" U_FLAG "vw:W:xXy:Yz:Z:")) != -1)

                switch (op) {
 
                case 'a':
                switch (op) {
 
                case 'a':


@@ -696,6 +747,10 @@ main(int argc, char **argv)
                        }
                        break;
 
                        }
                        break;
 

+               case 'h':
+                       ++hflag;
+                       break;
+

                case 'i':
                        if (optarg[0] == '0' && optarg[1] == 0)
                                error("Invalid adapter index");
                case 'i':
                        if (optarg[0] == '0' && optarg[1] == 0)
                                error("Invalid adapter index");


@@ -743,6 +798,18 @@ main(int argc, char **argv)
                        break;
 #endif /* HAVE_PCAP_CREATE */
 
                        break;
 #endif /* HAVE_PCAP_CREATE */
 

+#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
+               case 'j':
+                       jflag = pcap_tstamp_type_name_to_val(optarg);
+                       if (jflag < 0)
+                               error("invalid time stamp type %s", optarg);
+                       break;
+
+               case 'J':
+                       Jflag++;
+                       break;
+#endif
+

                case 'l':
 #ifdef WIN32
                        /*
                case 'l':
 #ifdef WIN32
                        /*


@@ -1035,6 +1102,10 @@ main(int argc, char **argv)
                pd = pcap_create(device, ebuf);
                if (pd == NULL)
                        error("%s", ebuf);
                pd = pcap_create(device, ebuf);
                if (pd == NULL)
                        error("%s", ebuf);

+#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
+               if (Jflag)
+                       show_tstamp_types_and_exit(device, pd);
+#endif

                /*
                 * Is this an interface that supports monitor mode?
                 */
                /*
                 * Is this an interface that supports monitor mode?
                 */


@@ -1044,16 +1115,16 @@ main(int argc, char **argv)
                        supports_monitor_mode = 0;
                status = pcap_set_snaplen(pd, snaplen);
                if (status != 0)
                        supports_monitor_mode = 0;
                status = pcap_set_snaplen(pd, snaplen);
                if (status != 0)

-                       error("%s: pcap_set_snaplen failed: %s",
+                       error("%s: Can't set snapshot length: %s",

                            device, pcap_statustostr(status));
                status = pcap_set_promisc(pd, !pflag);
                if (status != 0)
                            device, pcap_statustostr(status));
                status = pcap_set_promisc(pd, !pflag);
                if (status != 0)

-                       error("%s: pcap_set_promisc failed: %s",
+                       error("%s: Can't set promiscuous mode: %s",

                            device, pcap_statustostr(status));
                if (Iflag) {
                        status = pcap_set_rfmon(pd, 1);
                        if (status != 0)
                            device, pcap_statustostr(status));
                if (Iflag) {
                        status = pcap_set_rfmon(pd, 1);
                        if (status != 0)

-                               error("%s: pcap_set_rfmon failed: %s",
+                               error("%s: Can't set monitor mode: %s",

                                    device, pcap_statustostr(status));
                }
                status = pcap_set_timeout(pd, 1000);
                                    device, pcap_statustostr(status));
                }
                status = pcap_set_timeout(pd, 1000);


@@ -1063,9 +1134,17 @@ main(int argc, char **argv)
                if (Bflag != 0) {
                        status = pcap_set_buffer_size(pd, Bflag);
                        if (status != 0)
                if (Bflag != 0) {
                        status = pcap_set_buffer_size(pd, Bflag);
                        if (status != 0)

-                               error("%s: pcap_set_buffer_size failed: %s",
+                               error("%s: Can't set buffer size: %s",

                                    device, pcap_statustostr(status));
                }
                                    device, pcap_statustostr(status));
                }

+#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
+                if (jflag != -1) {
+                       status = pcap_set_tstamp_type(pd, jflag);
+                       if (status < 0)
+                               error("%s: Can't set time stamp type: %s",
+                                   device, pcap_statustostr(status));
+               }
+#endif

                status = pcap_activate(pd);
                if (status < 0) {
                        /*
                status = pcap_activate(pd);
                if (status < 0) {
                        /*


@@ -1179,6 +1258,30 @@ main(int argc, char **argv)
                (void)setsignal(SIGHUP, oldhandler);
 #endif /* WIN32 */
 
                (void)setsignal(SIGHUP, oldhandler);
 #endif /* WIN32 */
 

+#ifndef WIN32
+       /*
+        * If a user name was specified with "-Z", attempt to switch to
+        * that user's UID.  This would probably be used with sudo,
+        * to allow tcpdump to be run in a special restricted
+        * account (if you just want to allow users to open capture
+        * devices, and can't just give users that permission,
+        * you'd make tcpdump set-UID or set-GID).
+        *
+        * Tcpdump doesn't necessarily write only to one savefile;
+        * the general only way to allow a -Z instance to write to
+        * savefiles as the user under whose UID it's run, rather
+        * than as the user specified with -Z, would thus be to switch
+        * to the original user ID before opening a capture file and
+        * then switch back to the -Z user ID after opening the savefile.
+        * Switching to the -Z user ID only after opening the first
+        * savefile doesn't handle the general case.
+        */
+       if (getuid() == 0 || geteuid() == 0) {
+               if (username || chroot_dir)
+                       droproot(username, chroot_dir);
+       }
+#endif /* WIN32 */
+

        if (pcap_setfilter(pd, &fcode) < 0)
                error("%s", pcap_geterr(pd));
        if (WFileName) {
        if (pcap_setfilter(pd, &fcode) < 0)
                error("%s", pcap_geterr(pd));
        if (WFileName) {


@@ -1208,6 +1311,10 @@ main(int argc, char **argv)
                        callback = dump_packet;
                        pcap_userdata = (u_char *)p;
                }
                        callback = dump_packet;
                        pcap_userdata = (u_char *)p;
                }

+#ifdef HAVE_PCAP_DUMP_FLUSH
+               if (Uflag)
+                       pcap_dump_flush(p);
+#endif

        } else {
                type = pcap_datalink(pd);
                 printinfo.ndo_type = 1;
        } else {
                type = pcap_datalink(pd);
                 printinfo.ndo_type = 1;


@@ -1228,16 +1335,7 @@ main(int argc, char **argv)
                callback = print_packet;
                pcap_userdata = (u_char *)&printinfo;
        }
                callback = print_packet;
                pcap_userdata = (u_char *)&printinfo;
        }

-#ifndef WIN32
-       /*
-        * We cannot do this earlier, because we want to be able to open
-        * the file (if done) for writing before giving up permissions.
-        */
-       if (getuid() == 0 || geteuid() == 0) {
-               if (username || chroot_dir)
-                       droproot(username, chroot_dir);
-       }
-#endif /* WIN32 */
+

 #ifdef SIGINFO
        /*
         * We can't get statistics when reading from a file rather
 #ifdef SIGINFO
        /*
         * We can't get statistics when reading from a file rather


@@ -1783,17 +1881,17 @@ usage(void)
 #endif /* WIN32 */
 #endif /* HAVE_PCAP_LIB_VERSION */
        (void)fprintf(stderr,
 #endif /* WIN32 */
 #endif /* HAVE_PCAP_LIB_VERSION */
        (void)fprintf(stderr,

-"Usage: %s [-aAbd" D_FLAG "ef" I_FLAG "KlLnNOpqRStu" U_FLAG "vxX]" B_FLAG_USAGE " [ -c count ]\n", program_name);
+"Usage: %s [-aAbd" D_FLAG "efh" I_FLAG J_FLAG "KlLnNOpqRStu" U_FLAG "vxX]" B_FLAG_USAGE " [ -c count ]\n", program_name);

        (void)fprintf(stderr,
 "\t\t[ -C file_size ] [ -E algo:secret ] [ -F file ] [ -G seconds ]\n");
        (void)fprintf(stderr,
        (void)fprintf(stderr,
 "\t\t[ -C file_size ] [ -E algo:secret ] [ -F file ] [ -G seconds ]\n");
        (void)fprintf(stderr,

-"\t\t[ -i interface ] [ -M secret ] [ -r file ]\n");
+"\t\t[ -i interface ]" j_FLAG_USAGE " [ -M secret ]\n");

        (void)fprintf(stderr,
        (void)fprintf(stderr,

-"\t\t[ -s snaplen ] [ -T type ] [ -w file ] [ -W filecount ]\n");
+"\t\t[ -r file ] [ -s snaplen ] [ -T type ] [ -w file ]\n");

        (void)fprintf(stderr,
        (void)fprintf(stderr,

-"\t\t[ -y datalinktype ] [ -z command ] [ -Z user ]\n");
+"\t\t[ -W filecount ] [ -y datalinktype ] [ -z command ]\n");

        (void)fprintf(stderr,
        (void)fprintf(stderr,

-"\t\t[ expression ]\n");
+"\t\t[ -Z user ] [ expression ]\n");

        exit(1);
 }
 
        exit(1);
 }