]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-llc.c
CVE-2017-13687/CHDLC: Improve bounds and length checks.
[tcpdump] / print-llc.c
index 0132bdaa6b9ccecc7d0390a29c69abc6051bd7e4..6bdf599846ed6750f165811fcff122e83127d828 100644 (file)
  *     with an awful lot of hacking by Jeffrey Mogul, DECWRL
  */
 
+/* \summary: IEEE 802.2 LLC printer */
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include <tcpdump-stdinc.h>
+#include <netdissect-stdinc.h>
 
-#include "interface.h"
+#include "netdissect.h"
 #include "addrtoname.h"
-#include "extract.h"                   /* must come after interface.h */
+#include "extract.h"
 
 #include "llc.h"
 #include "ethertype.h"
@@ -146,21 +148,21 @@ static const struct oui_tok oui_to_tok[] = {
  */
 int
 llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
-         const u_char *esrc, const u_char *edst)
+         const struct lladdr_info *src, const struct lladdr_info *dst)
 {
        uint8_t dsap_field, dsap, ssap_field, ssap;
        uint16_t control;
-       u_int hdrlen;
+       int hdrlen;
        int is_u;
 
        if (caplen < 3) {
                ND_PRINT((ndo, "[|llc]"));
-               ND_DEFAULTPRINT((u_char *)p, caplen);
+               ND_DEFAULTPRINT((const u_char *)p, caplen);
                return (caplen);
        }
        if (length < 3) {
                ND_PRINT((ndo, "[|llc]"));
-               ND_DEFAULTPRINT((u_char *)p, caplen);
+               ND_DEFAULTPRINT((const u_char *)p, caplen);
                return (length);
        }
 
@@ -187,12 +189,12 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                 */
                if (caplen < 4) {
                        ND_PRINT((ndo, "[|llc]"));
-                       ND_DEFAULTPRINT((u_char *)p, caplen);
+                       ND_DEFAULTPRINT((const u_char *)p, caplen);
                        return (caplen);
                }
                if (length < 4) {
                        ND_PRINT((ndo, "[|llc]"));
-                       ND_DEFAULTPRINT((u_char *)p, caplen);
+                       ND_DEFAULTPRINT((const u_char *)p, caplen);
                        return (length);
                }
 
@@ -230,6 +232,22 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
        dsap = dsap_field & ~LLC_IG;
        ssap = ssap_field & ~LLC_GSAP;
 
+       if (ndo->ndo_eflag) {
+                ND_PRINT((ndo, "LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
+                       tok2str(llc_values, "Unknown", dsap),
+                       dsap,
+                       tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
+                       tok2str(llc_values, "Unknown", ssap),
+                       ssap,
+                       tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP)));
+
+               if (is_u) {
+                       ND_PRINT((ndo, ", ctrl 0x%02x: ", control));
+               } else {
+                       ND_PRINT((ndo, ", ctrl 0x%04x: ", control));
+               }
+       }
+
        /*
         * Skip LLC header.
         */
@@ -237,13 +255,6 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
        length -= hdrlen;
        caplen -= hdrlen;
 
-       /*
-        * Check for SNAP UI packets; if we have one, there's no point
-        * in printing the LLC header information, as we already know it -
-        * the relevant protocol-selection information is the SNAP OUI
-        * and PID, so it's sufficient to print that for frames we
-        * don't know how to print and for the "-e" flag.
-        */
        if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
            && control == LLC_UI) {
                /*
@@ -251,7 +262,7 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                 * Does anybody ever bridge one form of LAN traffic
                 * over a networking type that uses 802.2 LLC?
                 */
-               if (!snap_print(ndo, p, length, caplen, esrc, edst, 2)) {
+               if (!snap_print(ndo, p, length, caplen, src, dst, 2)) {
                        /*
                         * Unknown packet type; tell our caller, by
                         * returning a negative value, so they
@@ -262,22 +273,6 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                        return (hdrlen + 5);    /* include LLC and SNAP header */
        }
 
-       if (ndo->ndo_eflag) {
-                ND_PRINT((ndo, "LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
-                       tok2str(llc_values, "Unknown", dsap),
-                       dsap,
-                       tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
-                       tok2str(llc_values, "Unknown", ssap),
-                       ssap,
-                       tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP)));
-
-               if (is_u) {
-                       ND_PRINT((ndo, ", ctrl 0x%02x: ", control));
-               } else {
-                       ND_PRINT((ndo, ", ctrl 0x%04x: ", control));
-               }
-       }
-
        if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
            control == LLC_UI) {
                stp_print(ndo, p, length);
@@ -310,7 +305,7 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                return (hdrlen);
        }
 
-#ifdef TCPDUMP_DO_SMB
+#ifdef ENABLE_SMB
        if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
            && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
                /*
@@ -335,23 +330,23 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
 
        if (!ndo->ndo_eflag) {
                if (ssap == dsap) {
-                       if (esrc == NULL || edst == NULL)
+                       if (src == NULL || dst == NULL)
                                ND_PRINT((ndo, "%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
                        else
                                ND_PRINT((ndo, "%s > %s %s ",
-                                               etheraddr_string(ndo, esrc),
-                                               etheraddr_string(ndo, edst),
+                                               (src->addr_string)(ndo, src->addr),
+                                               (dst->addr_string)(ndo, dst->addr),
                                                tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
                } else {
-                       if (esrc == NULL || edst == NULL)
+                       if (src == NULL || dst == NULL)
                                ND_PRINT((ndo, "%s > %s ",
                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
                                        tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
                        else
                                ND_PRINT((ndo, "%s %s > %s %s ",
-                                       etheraddr_string(ndo, esrc),
+                                       (src->addr_string)(ndo, src->addr),
                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
-                                       etheraddr_string(ndo, edst),
+                                       (dst->addr_string)(ndo, dst->addr),
                                        tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
                }
        }
@@ -363,8 +358,27 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                        length + hdrlen));
 
                if ((control & ~LLC_U_POLL) == LLC_XID) {
+                       if (length == 0) {
+                               /*
+                                * XID with no payload.
+                                * This could, for example, be an SNA
+                                * "short form" XID.
+                                 */
+                               return (hdrlen);
+                       }
+                       if (caplen < 1) {
+                               ND_PRINT((ndo, "[|llc]"));
+                               if (caplen > 0)
+                                       ND_DEFAULTPRINT((const u_char *)p, caplen);
+                               return (hdrlen);
+                       }
                        if (*p == LLC_XID_FI) {
-                               ND_PRINT((ndo, ": %02x %02x", p[1], p[2]));
+                               if (caplen < 3 || length < 3) {
+                                       ND_PRINT((ndo, "[|llc]"));
+                                       if (caplen > 0)
+                                               ND_DEFAULTPRINT((const u_char *)p, caplen);
+                               } else
+                                       ND_PRINT((ndo, ": %02x %02x", p[1], p[2]));
                                return (hdrlen);
                        }
                }
@@ -387,35 +401,25 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
        return (-hdrlen);
 }
 
-static void
-snap_hdr_print(netdissect_options *ndo, const uint8_t *esrc, const uint8_t *edst,
-       uint32_t orgcode, u_short et, u_int length)
+static const struct tok *
+oui_to_struct_tok(uint32_t orgcode)
 {
        const struct tok *tok = null_values;
        const struct oui_tok *otp;
 
-       if (esrc != NULL && edst != NULL) {
-               ND_PRINT((ndo, "%s > %s ",
-                               etheraddr_string(ndo, esrc),
-                               etheraddr_string(ndo, edst)));
-       }
        for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
                if (otp->oui == orgcode) {
                        tok = otp->tok;
                        break;
                }
        }
-       ND_PRINT((ndo, "SNAP oui %s (0x%06x), %s %s (0x%04x), length %u: ",
-            tok2str(oui_values, "Unknown", orgcode),
-            orgcode,
-            (orgcode == 0x000000 ? "ethertype" : "pid"),
-            tok2str(tok, "Unknown", et),
-            et, length));
+       return (tok);
 }
 
 int
 snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
-       const u_char *esrc, const u_char *edst, u_int bridge_pad)
+       const struct lladdr_info *src, const struct lladdr_info *dst,
+       u_int bridge_pad)
 {
        uint32_t orgcode;
        register u_short et;
@@ -430,9 +434,15 @@ snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
        if (ndo->ndo_eflag) {
                /*
                 * Somebody's already printed the MAC addresses, if there
-                * are any, so just print the SNAP header.
+                * are any, so just print the SNAP header, not the MAC
+                * addresses.
                 */
-               snap_hdr_print(ndo, NULL, NULL, orgcode, et, length - 5);
+               ND_PRINT((ndo, "oui %s (0x%06x), %s %s (0x%04x), length %u: ",
+                    tok2str(oui_values, "Unknown", orgcode),
+                    orgcode,
+                    (orgcode == 0x000000 ? "ethertype" : "pid"),
+                    tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
+                    et, length - 5));
        }
        p += 5;
        length -= 5;
@@ -447,7 +457,7 @@ snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                 * Cisco hardware; the protocol ID is
                 * an Ethernet protocol type.
                 */
-               ret = ethertype_print(ndo, et, p, length, caplen);
+               ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
                if (ret)
                        return (ret);
                break;
@@ -462,7 +472,7 @@ snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                         * but used 0x000000 and an Ethernet
                         * packet type for AARP packets.
                         */
-                       ret = ethertype_print(ndo, et, p, length, caplen);
+                       ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
                        if (ret)
                                return (ret);
                }
@@ -561,8 +571,33 @@ snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                        return (1);
                }
        }
-       if (!ndo->ndo_eflag)
-               snap_hdr_print(ndo, esrc, edst, orgcode, et, length);
+       if (!ndo->ndo_eflag) {
+               /*
+                * Nobody printed the link-layer addresses, so print them, if
+                * we have any.
+                */
+               if (src != NULL && dst != NULL) {
+                       ND_PRINT((ndo, "%s > %s ",
+                               (src->addr_string)(ndo, src->addr),
+                               (dst->addr_string)(ndo, dst->addr)));
+               }
+               /*
+                * Print the SNAP header, but if the OUI is 000000, don't
+                * bother printing it, and report the PID as being an
+                * ethertype.
+                */
+               if (orgcode == 0x000000) {
+                       ND_PRINT((ndo, "SNAP, ethertype %s (0x%04x), length %u: ",
+                            tok2str(ethertype_values, "Unknown", et),
+                            et, length));
+               } else {
+                       ND_PRINT((ndo, "SNAP, oui %s (0x%06x), pid %s (0x%04x), length %u: ",
+                            tok2str(oui_values, "Unknown", orgcode),
+                            orgcode,
+                            tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
+                            et, length));
+               }
+       }
        return (0);
 
 trunc: