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-rw-r--r--epan/asn1.c284
1 files changed, 284 insertions, 0 deletions
diff --git a/epan/asn1.c b/epan/asn1.c
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+++ b/epan/asn1.c
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+/* asn1.c
+ * Common routines for ASN.1
+ * 2007 Anders Broman
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+
+#include <glib.h>
+
+#include <string.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include <epan/packet.h>
+
+#include "asn1.h"
+
+void asn1_ctx_init(asn1_ctx_t *actx, asn1_enc_e encoding, bool aligned, packet_info *pinfo) {
+ memset(actx, '\0', sizeof(*actx));
+ actx->signature = ASN1_CTX_SIGNATURE;
+ actx->encoding = encoding;
+ actx->aligned = aligned;
+ actx->pinfo = pinfo;
+}
+
+bool asn1_ctx_check_signature(asn1_ctx_t *actx) {
+ return actx && (actx->signature == ASN1_CTX_SIGNATURE);
+}
+
+void asn1_ctx_clean_external(asn1_ctx_t *actx) {
+ memset(&actx->external, '\0', sizeof(actx->external));
+ actx->external.hf_index = -1;
+ actx->external.encoding = -1;
+}
+
+void asn1_ctx_clean_epdv(asn1_ctx_t *actx) {
+ memset(&actx->embedded_pdv, '\0', sizeof(actx->embedded_pdv));
+ actx->embedded_pdv.hf_index = -1;
+ actx->embedded_pdv.identification = -1;
+}
+
+
+/*--- stack/parameters ---*/
+
+void asn1_stack_frame_push(asn1_ctx_t *actx, const gchar *name) {
+ asn1_stack_frame_t *frame;
+
+ frame = wmem_new0(actx->pinfo->pool, asn1_stack_frame_t);
+ frame->name = name;
+ frame->next = actx->stack;
+ actx->stack = frame;
+}
+
+void asn1_stack_frame_pop(asn1_ctx_t *actx, const gchar *name) {
+ DISSECTOR_ASSERT(actx->stack);
+ DISSECTOR_ASSERT(!strcmp(actx->stack->name, name));
+ actx->stack = actx->stack->next;
+}
+
+void asn1_stack_frame_check(asn1_ctx_t *actx, const gchar *name, const asn1_par_def_t *par_def) {
+ const asn1_par_def_t *pd = par_def;
+ asn1_par_t *par;
+
+ DISSECTOR_ASSERT(actx->stack);
+ DISSECTOR_ASSERT(!strcmp(actx->stack->name, name));
+
+ par = actx->stack->par;
+ while (pd->name) {
+ DISSECTOR_ASSERT(par);
+ DISSECTOR_ASSERT((pd->ptype == ASN1_PAR_IRR) || (par->ptype == pd->ptype));
+ par->name = pd->name;
+ pd++;
+ par = par->next;
+ }
+ DISSECTOR_ASSERT(!par);
+}
+
+static asn1_par_t *get_par_by_name(asn1_ctx_t *actx, const gchar *name) {
+ asn1_par_t *par = NULL;
+
+ DISSECTOR_ASSERT(actx->stack);
+ par = actx->stack->par;
+ while (par) {
+ if (!strcmp(par->name, name))
+ return par;
+ par = par->next;
+ }
+ return par;
+}
+
+static asn1_par_t *push_new_par(asn1_ctx_t *actx) {
+ asn1_par_t *par, **pp;
+
+ DISSECTOR_ASSERT(actx->stack);
+
+ par = wmem_new0(actx->pinfo->pool, asn1_par_t);
+
+ pp = &(actx->stack->par);
+ while (*pp)
+ pp = &((*pp)->next);
+ *pp = par;
+
+ return par;
+}
+
+void asn1_param_push_boolean(asn1_ctx_t *actx, bool value) {
+ asn1_par_t *par;
+
+ par = push_new_par(actx);
+ par->ptype = ASN1_PAR_BOOLEAN;
+ par->value.v_boolean = value;
+}
+
+void asn1_param_push_integer(asn1_ctx_t *actx, gint32 value) {
+ asn1_par_t *par;
+
+ par = push_new_par(actx);
+ par->ptype = ASN1_PAR_INTEGER;
+ par->value.v_integer = value;
+}
+
+bool asn1_param_get_boolean(asn1_ctx_t *actx, const gchar *name) {
+ asn1_par_t *par = NULL;
+
+ par = get_par_by_name(actx, name);
+ DISSECTOR_ASSERT(par);
+ return par->value.v_boolean;
+}
+
+gint32 asn1_param_get_integer(asn1_ctx_t *actx, const gchar *name) {
+ asn1_par_t *par = NULL;
+
+ par = get_par_by_name(actx, name);
+ DISSECTOR_ASSERT(par);
+ return par->value.v_integer;
+}
+
+
+/*--- ROSE ---*/
+
+void rose_ctx_init(rose_ctx_t *rctx) {
+ memset(rctx, '\0', sizeof(*rctx));
+ rctx->signature = ROSE_CTX_SIGNATURE;
+}
+
+bool rose_ctx_check_signature(rose_ctx_t *rctx) {
+ return rctx && (rctx->signature == ROSE_CTX_SIGNATURE);
+}
+
+void rose_ctx_clean_data(rose_ctx_t *rctx) {
+ memset(&rctx->d, '\0', sizeof(rctx->d));
+ rctx->d.code = -1;
+}
+
+asn1_ctx_t *get_asn1_ctx(void *ptr) {
+ asn1_ctx_t *actx = (asn1_ctx_t*)ptr;
+
+ if (!asn1_ctx_check_signature(actx))
+ actx = NULL;
+
+ return actx;
+}
+
+rose_ctx_t *get_rose_ctx(void *ptr) {
+ rose_ctx_t *rctx = (rose_ctx_t*)ptr;
+ asn1_ctx_t *actx = (asn1_ctx_t*)ptr;
+
+ if (!asn1_ctx_check_signature(actx))
+ actx = NULL;
+
+ if (actx)
+ rctx = actx->rose_ctx;
+
+ if (!rose_ctx_check_signature(rctx))
+ rctx = NULL;
+
+ return rctx;
+}
+
+/** Only tested for BER */
+double asn1_get_real(const guint8 *real_ptr, gint len) {
+ guint8 octet;
+ const guint8 *p;
+ guint8 *buf;
+ double val = 0;
+
+ /* 8.5.2 If the real value is the value zero,
+ * there shall be no contents octets in the encoding.
+ */
+ if (len < 1) return val;
+
+ octet = real_ptr[0];
+ p = real_ptr + 1;
+ len -= 1;
+ if (octet & 0x80) { /* binary encoding */
+ int i;
+ bool Eneg;
+ gint8 S; /* Sign */
+ guint8 B; /* Base */
+ guint8 F; /* scaling Factor */
+ gint32 E = 0; /* Exponent (supported max 3 octets/24 bit) */
+ guint64 N = 0; /* N (supported max 8 octets/64 bit) */
+
+ guint8 lenE, lenN;
+
+ if(octet & 0x40) S = -1; else S = 1;
+ switch(octet & 0x30) {
+ case 0x00: B = 2; break;
+ case 0x10: B = 8; break;
+ case 0x20: B = 16; break;
+ case 0x30: /* Reserved */
+ default:
+ /* TODO Add some warning in tree about reserved value for Base */
+ return 0;
+ }
+ F = (octet & 0x0c) >> 2;
+
+ /* 8.5.6.4 Exponent length */
+ lenE = (octet & 0x3) + 1;
+
+ /* we can't handle exponents > 24 bits */
+ /* TODO Next octet(s) define length of exponent */
+ DISSECTOR_ASSERT(lenE != 4);
+
+ /* Ensure the buffer len and its content are coherent */
+ DISSECTOR_ASSERT(lenE < len - 1);
+
+ Eneg = ((*p) & 0x80) ? TRUE : FALSE;
+ for (i = 0; i < lenE; i++) {
+ if(Eneg) {
+ /* 2's complement: inverse bits */
+ E = (E<<8) | ((guint8) ~(*p));
+ } else {
+ E = (E<<8) | *p;
+ }
+ p++;
+ }
+ if(Eneg) {
+ /* 2's complement: ... and add 1 (and make negative of course) */
+ E = -(E + 1);
+ }
+
+ lenN = len - lenE;
+
+ /* we can't handle integers > 64 bits */
+ DISSECTOR_ASSERT(lenN <= 8);
+
+ for (i=0; i<lenN; i++) {
+ N = (N<<8) | *p;
+ p++;
+ }
+ val = (double) S * N * pow(2, F) * pow(B, E);
+ } else if (octet & 0x40) { /* SpecialRealValue */
+ switch (octet & 0x3F) {
+ case 0x00: val = HUGE_VAL; break;
+ case 0x01: val = -HUGE_VAL; break;
+ }
+ } else { /* decimal encoding */
+ buf = g_strndup(p, len);
+ val = g_ascii_strtod(buf, NULL);
+ g_free(buf);
+ }
+
+ return val;
+}
+
+/*
+ * Editor modelines - https://www.wireshark.org/tools/modelines.html
+ *
+ * Local Variables:
+ * c-basic-offset: 2
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set shiftwidth=2 tabstop=8 expandtab:
+ * :indentSize=2:tabSize=8:noTabs=true:
+ */
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