]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-llc.c
CVE-2017-13687/CHDLC: Improve bounds and length checks.
[tcpdump] / print-llc.c
index 597773bb25722809a8c9997493edf4266ed0fe2c..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 <stdio.h>
-#include <string.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"
@@ -126,7 +125,7 @@ static const struct tok null_values[] = {
 };
 
 struct oui_tok {
-       u_int32_t       oui;
+       uint32_t        oui;
        const struct tok *tok;
 };
 
@@ -140,23 +139,31 @@ static const struct oui_tok oui_to_tok[] = {
 };
 
 /*
- * Returns non-zero IFF it succeeds in printing the header
+ * If we printed information about the payload, returns the length of the LLC
+ * header, plus the length of any SNAP header following it.
+ *
+ * Otherwise (for example, if the packet has unknown SAPs or has a SNAP
+ * header with an unknown OUI/PID combination), returns the *negative*
+ * of that value.
  */
 int
-llc_print(const u_char *p, u_int length, u_int caplen,
-         const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
+llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
+         const struct lladdr_info *src, const struct lladdr_info *dst)
 {
-       u_int8_t dsap_field, dsap, ssap_field, ssap;
-       u_int16_t control;
+       uint8_t dsap_field, dsap, ssap_field, ssap;
+       uint16_t control;
+       int hdrlen;
        int is_u;
-       register int ret;
-
-       *extracted_ethertype = 0;
 
        if (caplen < 3) {
-               (void)printf("[|llc]");
-               default_print((u_char *)p, caplen);
-               return(0);
+               ND_PRINT((ndo, "[|llc]"));
+               ND_DEFAULTPRINT((const u_char *)p, caplen);
+               return (caplen);
+       }
+       if (length < 3) {
+               ND_PRINT((ndo, "[|llc]"));
+               ND_DEFAULTPRINT((const u_char *)p, caplen);
+               return (length);
        }
 
        dsap_field = *p;
@@ -174,15 +181,21 @@ llc_print(const u_char *p, u_int length, u_int caplen,
                 * U frame.
                 */
                is_u = 1;
+               hdrlen = 3;     /* DSAP, SSAP, 1-byte control field */
        } else {
                /*
                 * The control field in I and S frames is
                 * 2 bytes...
                 */
                if (caplen < 4) {
-                       (void)printf("[|llc]");
-                       default_print((u_char *)p, caplen);
-                       return(0);
+                       ND_PRINT((ndo, "[|llc]"));
+                       ND_DEFAULTPRINT((const u_char *)p, caplen);
+                       return (caplen);
+               }
+               if (length < 4) {
+                       ND_PRINT((ndo, "[|llc]"));
+                       ND_DEFAULTPRINT((const u_char *)p, caplen);
+                       return (length);
                }
 
                /*
@@ -190,6 +203,7 @@ llc_print(const u_char *p, u_int length, u_int caplen,
                 */
                control = EXTRACT_LE_16BITS(p + 2);
                is_u = 0;
+               hdrlen = 4;     /* DSAP, SSAP, 2-byte control field */
        }
 
        if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
@@ -208,42 +222,73 @@ llc_print(const u_char *p, u_int length, u_int caplen,
                 * least one capture file.)
                 */
 
-            if (eflag)
-               printf("IPX 802.3: ");
+            if (ndo->ndo_eflag)
+               ND_PRINT((ndo, "IPX 802.3: "));
 
-            ipx_print(p, length);
-            return (1);
+            ipx_print(ndo, p, length);
+            return (0);                /* no LLC header */
        }
 
        dsap = dsap_field & ~LLC_IG;
        ssap = ssap_field & ~LLC_GSAP;
 
-       if (eflag) {
-                printf("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
+       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));
+                       tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP)));
 
                if (is_u) {
-                       printf(", ctrl 0x%02x: ", control);
+                       ND_PRINT((ndo, ", ctrl 0x%02x: ", control));
                } else {
-                       printf(", ctrl 0x%04x: ", control);
+                       ND_PRINT((ndo, ", ctrl 0x%04x: ", control));
                }
        }
 
+       /*
+        * Skip LLC header.
+        */
+       p += hdrlen;
+       length -= hdrlen;
+       caplen -= hdrlen;
+
+       if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
+           && control == LLC_UI) {
+               /*
+                * XXX - what *is* the right bridge pad value here?
+                * 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, src, dst, 2)) {
+                       /*
+                        * Unknown packet type; tell our caller, by
+                        * returning a negative value, so they
+                        * can print the raw packet.
+                        */
+                       return (-(hdrlen + 5)); /* include LLC and SNAP header */
+               } else
+                       return (hdrlen + 5);    /* include LLC and SNAP header */
+       }
+
        if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
            control == LLC_UI) {
-               stp_print(p+3, length-3);
-               return (1);
+               stp_print(ndo, p, length);
+               return (hdrlen);
        }
 
        if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
            control == LLC_UI) {
-               ip_print(gndo, p+4, length-4);
-               return (1);
+               /*
+                * This is an RFC 948-style IP packet, with
+                * an 802.3 header and an 802.2 LLC header
+                * with the source and destination SAPs being
+                * the IP SAP.
+                */
+               ip_print(ndo, p, length);
+               return (hdrlen);
        }
 
        if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
@@ -252,17 +297,15 @@ llc_print(const u_char *p, u_int length, u_int caplen,
                 * This is an Ethernet_802.2 IPX frame, with an 802.3
                 * header and an 802.2 LLC header with the source and
                 * destination SAPs being the IPX SAP.
-                *
-                * Skip DSAP, LSAP, and control field.
                 */
-                if (eflag)
-                        printf("IPX 802.2: ");
+                if (ndo->ndo_eflag)
+                        ND_PRINT((ndo, "IPX 802.2: "));
 
-               ipx_print(p+3, length-3);
-               return (1);
+               ipx_print(ndo, p, length);
+               return (hdrlen);
        }
 
-#ifdef TCPDUMP_DO_SMB
+#ifdef ENABLE_SMB
        if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
            && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
                /*
@@ -275,130 +318,131 @@ llc_print(const u_char *p, u_int length, u_int caplen,
                 * LLC_S_FMT, set in the first byte of the control field)
                 * and UI frames (whose control field is just 3, LLC_U_FMT).
                 */
-
-               /*
-                * Skip the LLC header.
-                */
-               if (is_u) {
-                       p += 3;
-                       length -= 3;
-                       caplen -= 3;
-               } else {
-                       p += 4;
-                       length -= 4;
-                       caplen -= 4;
-               }
-               netbeui_print(control, p, length);
-               return (1);
+               netbeui_print(ndo, control, p, length);
+               return (hdrlen);
        }
 #endif
        if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
            && control == LLC_UI) {
-               isoclns_print(p + 3, length - 3, caplen - 3);
-               return (1);
-       }
-
-       if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
-           && control == LLC_UI) {
-               /*
-                * XXX - what *is* the right bridge pad value here?
-                * Does anybody ever bridge one form of LAN traffic
-                * over a networking type that uses 802.2 LLC?
-                */
-               ret = snap_print(p+3, length-3, caplen-3, 2);
-               if (ret)
-                       return (ret);
+               isoclns_print(ndo, p, length, caplen);
+               return (hdrlen);
        }
 
-       if (!eflag) {
+       if (!ndo->ndo_eflag) {
                if (ssap == dsap) {
-                       if (esrc == NULL || edst == NULL)
-                               (void)printf("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
+                       if (src == NULL || dst == NULL)
+                               ND_PRINT((ndo, "%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
                        else
-                               (void)printf("%s > %s %s ",
-                                               etheraddr_string(esrc),
-                                               etheraddr_string(edst),
-                                               tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
+                               ND_PRINT((ndo, "%s > %s %s ",
+                                               (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)
-                               (void)printf("%s > %s ",
+                       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));
+                                       tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
                        else
-                               (void)printf("%s %s > %s %s ",
-                                       etheraddr_string(esrc),
+                               ND_PRINT((ndo, "%s %s > %s %s ",
+                                       (src->addr_string)(ndo, src->addr),
                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
-                                       etheraddr_string(edst),
-                                       tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
+                                       (dst->addr_string)(ndo, dst->addr),
+                                       tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
                }
        }
 
        if (is_u) {
-               printf("Unnumbered, %s, Flags [%s], length %u",
+               ND_PRINT((ndo, "Unnumbered, %s, Flags [%s], length %u",
                        tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
                        tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
-                       length);
-
-               p += 3;
-               length -= 3;
-               caplen -= 3;
+                       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) {
-                               printf(": %02x %02x", p[1], p[2]);
-                               p += 3;
-                               length -= 3;
-                               caplen -= 3;
+                               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);
                        }
                }
        } else {
                if ((control & LLC_S_FMT) == LLC_S_FMT) {
-                       (void)printf("Supervisory, %s, rcv seq %u, Flags [%s], length %u",
+                       ND_PRINT((ndo, "Supervisory, %s, rcv seq %u, Flags [%s], length %u",
                                tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
                                LLC_IS_NR(control),
                                tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
-                                length);
+                                length + hdrlen));
+                       return (hdrlen);        /* no payload to print */
                } else {
-                       (void)printf("Information, send seq %u, rcv seq %u, Flags [%s], length %u",
+                       ND_PRINT((ndo, "Information, send seq %u, rcv seq %u, Flags [%s], length %u",
                                LLC_I_NS(control),
                                LLC_IS_NR(control),
                                tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
-                                length);
+                                length + hdrlen));
+               }
+       }
+       return (-hdrlen);
+}
+
+static const struct tok *
+oui_to_struct_tok(uint32_t orgcode)
+{
+       const struct tok *tok = null_values;
+       const struct oui_tok *otp;
+
+       for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
+               if (otp->oui == orgcode) {
+                       tok = otp->tok;
+                       break;
                }
-               p += 4;
-               length -= 4;
-               caplen -= 4;
        }
-       return(1);
+       return (tok);
 }
 
 int
-snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
+snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
+       const struct lladdr_info *src, const struct lladdr_info *dst,
+       u_int bridge_pad)
 {
-       u_int32_t orgcode;
+       uint32_t orgcode;
        register u_short et;
        register int ret;
 
-       TCHECK2(*p, 5);
+       ND_TCHECK2(*p, 5);
+       if (caplen < 5 || length < 5)
+               goto trunc;
        orgcode = EXTRACT_24BITS(p);
        et = EXTRACT_16BITS(p + 3);
 
-       if (eflag) {
-               const struct tok *tok = null_values;
-               const struct oui_tok *otp;
-
-               for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
-                       if (otp->oui == orgcode) {
-                               tok = otp->tok;
-                               break;
-                       }
-               }
-               (void)printf("oui %s (0x%06x), %s %s (0x%04x): ",
+       if (ndo->ndo_eflag) {
+               /*
+                * Somebody's already printed the MAC addresses, if there
+                * are any, so just print the SNAP header, not the MAC
+                * addresses.
+                */
+               ND_PRINT((ndo, "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);
+                    tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
+                    et, length - 5));
        }
        p += 5;
        length -= 5;
@@ -413,7 +457,7 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
                 * Cisco hardware; the protocol ID is
                 * an Ethernet protocol type.
                 */
-               ret = ethertype_print(gndo, et, p, length, caplen);
+               ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
                if (ret)
                        return (ret);
                break;
@@ -428,7 +472,7 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
                         * but used 0x000000 and an Ethernet
                         * packet type for AARP packets.
                         */
-                       ret = ethertype_print(gndo, et, p, length, caplen);
+                       ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
                        if (ret)
                                return (ret);
                }
@@ -437,24 +481,25 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
        case OUI_CISCO:
                 switch (et) {
                 case PID_CISCO_CDP:
-                        cdp_print(p, length, caplen);
+                        cdp_print(ndo, p, length, caplen);
                         return (1);
                 case PID_CISCO_DTP:
-                        dtp_print(p, length);
+                        dtp_print(ndo, p, length);
                         return (1);
                 case PID_CISCO_UDLD:
-                        udld_print(p, length);
+                        udld_print(ndo, p, length);
                         return (1);
                 case PID_CISCO_VTP:
-                        vtp_print(p, length);
+                        vtp_print(ndo, p, length);
                         return (1);
                 case PID_CISCO_PVST:
                 case PID_CISCO_VLANBRIDGE:
-                        stp_print(p, length);
+                        stp_print(ndo, p, length);
                         return (1);
                 default:
                         break;
                 }
+               break;
 
        case OUI_RFC2684:
                switch (et) {
@@ -468,7 +513,7 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
                        /*
                         * Skip the padding.
                         */
-                       TCHECK2(*p, bridge_pad);
+                       ND_TCHECK2(*p, bridge_pad);
                        caplen -= bridge_pad;
                        length -= bridge_pad;
                        p += bridge_pad;
@@ -476,7 +521,7 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
                        /*
                         * What remains is an Ethernet packet.
                         */
-                       ether_print(gndo, p, length, caplen, NULL, NULL);
+                       ether_print(ndo, p, length, caplen, NULL, NULL);
                        return (1);
 
                case PID_RFC2684_802_5_FCS:
@@ -489,7 +534,7 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
                         * Skip the padding, but not the Access
                         * Control field.
                         */
-                       TCHECK2(*p, bridge_pad);
+                       ND_TCHECK2(*p, bridge_pad);
                        caplen -= bridge_pad;
                        length -= bridge_pad;
                        p += bridge_pad;
@@ -498,7 +543,7 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
                         * What remains is an 802.5 Token Ring
                         * packet.
                         */
-                       token_print(p, length, caplen);
+                       token_print(ndo, p, length, caplen);
                        return (1);
 
                case PID_RFC2684_FDDI_FCS:
@@ -510,7 +555,7 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
                        /*
                         * Skip the padding.
                         */
-                       TCHECK2(*p, bridge_pad + 1);
+                       ND_TCHECK2(*p, bridge_pad + 1);
                        caplen -= bridge_pad + 1;
                        length -= bridge_pad + 1;
                        p += bridge_pad + 1;
@@ -518,18 +563,45 @@ snap_print(const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
                        /*
                         * What remains is an FDDI packet.
                         */
-                       fddi_print(p, length, caplen);
+                       fddi_print(ndo, p, length, caplen);
                        return (1);
 
                case PID_RFC2684_BPDU:
-                       stp_print(p, length);
+                       stp_print(ndo, p, length);
                        return (1);
                }
        }
+       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:
-       (void)printf("[|snap]");
+       ND_PRINT((ndo, "[|snap]"));
        return (1);
 }