CVE-2017-13030/PIM: Redo bounds checks and add length checks.

[tcpdump] / tcpdump.c

diff --git a/tcpdump.c b/tcpdump.c
index b76b426d691be1ceaf12862316a26772c9ba67ab..d9c7f7ab8f97677f1d0270fa8b429caa75487eec 100644 (file)
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -130,7 +130,7 @@ The Regents of the University of California.  All rights reserved.\n";
 #endif
 
 static int Bflag;                      /* buffer size */
-static int Cflag;                      /* rotate dump files after this many bytes */
+static long Cflag;                     /* rotate dump files after this many bytes */
 static int Cflag_count;                        /* Keep track of which file number we're writing */
 static int Dflag;                      /* list available devices and exit */
 /*
@@ -171,26 +171,17 @@ static int infoprint;
 char *program_name;
 
 /* Forwards */
-static void error(const char *, ...)
-     __attribute__((noreturn))
-#ifdef __ATTRIBUTE___FORMAT_OK
-     __attribute__((format (printf, 1, 2)))
-#endif /* __ATTRIBUTE___FORMAT_OK */
-     ;
-static void warning(const char *, ...)
-#ifdef __ATTRIBUTE___FORMAT_OK
-     __attribute__((format (printf, 1, 2)))
-#endif /* __ATTRIBUTE___FORMAT_OK */
-     ;
-static void exit_tcpdump(int) __attribute__((noreturn));
+static void error(FORMAT_STRING(const char *), ...) NORETURN PRINTFLIKE(1, 2);
+static void warning(FORMAT_STRING(const char *), ...) PRINTFLIKE(1, 2);
+static void exit_tcpdump(int) NORETURN;
 static RETSIGTYPE cleanup(int);
 static RETSIGTYPE child_cleanup(int);
 static void print_version(void);
 static void print_usage(void);
-static void show_tstamp_types_and_exit(pcap_t *, const char *device) __attribute__((noreturn));
-static void show_dlts_and_exit(pcap_t *, const char *device) __attribute__((noreturn));
+static void show_tstamp_types_and_exit(pcap_t *, const char *device) NORETURN;
+static void show_dlts_and_exit(pcap_t *, const char *device) NORETURN;
 #ifdef HAVE_PCAP_FINDALLDEVS
-static void show_devices_and_exit (void) __attribute__((noreturn));
+static void show_devices_and_exit (void) NORETURN;
 #endif
 
 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
@@ -458,7 +449,7 @@ show_devices_and_exit (void)
  * OS X tcpdump uses -g to force non--v output for IP to be on one
  * line, making it more "g"repable;
  *
- * OS X tcpdump uses -k tospecify that packet comments in pcap-ng files
+ * OS X tcpdump uses -k to specify that packet comments in pcap-ng files
  * should be printed;
  *
  * OpenBSD tcpdump uses -o to indicate that OS fingerprinting should be done
@@ -643,12 +634,13 @@ droproot(const char *username, const char *chroot_dir)
                exit_tcpdump(1);
        }
 #ifdef HAVE_LIBCAP_NG
-       /* We don't need CAP_SETUID and CAP_SETGID any more. */
+       /* We don't need CAP_SETUID, CAP_SETGID and CAP_SYS_CHROOT any more. */
        capng_updatev(
                CAPNG_DROP,
                CAPNG_EFFECTIVE | CAPNG_PERMITTED,
                CAP_SETUID,
                CAP_SETGID,
+               CAP_SYS_CHROOT,
                -1);
        capng_apply(CAPNG_SELECT_BOTH);
 #endif /* HAVE_LIBCAP_NG */
@@ -1045,9 +1037,9 @@ open_interface(const char *device, netdissect_options *ndo, char *ebuf)
                        /*
                         * Return an error for our caller to handle.
                         */
-                       pcap_close(pc);
                        snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s\n(%s)",
                            device, pcap_statustostr(status), cp);
+                       pcap_close(pc);
                        return (NULL);
                } else if (status == PCAP_ERROR_PERM_DENIED && *cp != '\0')
                        error("%s: %s\n(%s)", device,
@@ -1825,6 +1817,13 @@ main(int argc, char **argv)
                                CAP_SETGID,
                                -1);
                }
+               if (chroot_dir) {
+                       capng_update(
+                               CAPNG_ADD,
+                               CAPNG_PERMITTED | CAPNG_EFFECTIVE,
+                               CAP_SYS_CHROOT
+                               );
+               }
 
                if (WFileName) {
                        capng_update(
@@ -1847,7 +1846,12 @@ main(int argc, char **argv)
        if (RFileName == NULL && VFileName == NULL) {
                static const unsigned long cmds[] = { BIOCGSTATS, BIOCROTZBUF };
 
-               cap_rights_init(&rights, CAP_IOCTL, CAP_READ);
+               /*
+                * The various libpcap devices use a combination of
+                * read (bpf), ioctl (bpf, netmap), poll (netmap)
+                * so we add the relevant access rights.
+                */
+               cap_rights_init(&rights, CAP_IOCTL, CAP_READ, CAP_EVENT);
                if (cap_rights_limit(pcap_fileno(pd), &rights) < 0 &&
                    errno != ENOSYS) {
                        error("unable to limit pcap descriptor");
@@ -2322,6 +2326,7 @@ dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *s
                        if (Cflag == 0 && Wflag > 0 && Gflag_count >= Wflag) {
                                (void)fprintf(stderr, "Maximum file limit reached: %d\n",
                                    Wflag);
+                               info(1);
                                exit_tcpdump(0);
                                /* NOTREACHED */
                        }
@@ -2590,6 +2595,14 @@ print_version(void)
        smi_version_string = nd_smi_version_string();
        if (smi_version_string != NULL)
                (void)fprintf (stderr, "SMI-library: %s\n", smi_version_string);
+
+#if defined(__SANITIZE_ADDRESS__)
+       (void)fprintf (stderr, "Compiled with AddressSanitizer/GCC.\n");
+#elif defined(__has_feature)
+#  if __has_feature(address_sanitizer)
+       (void)fprintf (stderr, "Compiled with AddressSanitizer/CLang.\n");
+#  endif
+#endif /* __SANITIZE_ADDRESS__ or __has_feature */
 }
 USES_APPLE_RST