bssap_conn: fix missing length check

Check length of msg_new before trying to encode a copy of the IE into
it. The code path for IE_AOIP_TRASP_ADDR is different since it gets
replaced. With the libosmocore patch in Depends below the
gsm0808_enc_aoip_trasp_addr function checks the length.

Depends: libosmocore I632986b99d841abff0f14c6da65f030175f5c4a1
Fixes: Coverity CID#273004
Change-Id: I1fc4c81e139bab3d7d977ef9467f62d8088884db
changes/82/28582/5
Oliver Smith 5 months ago
parent 07180351c4
commit cce4b03bd3
  1. 30
      src/osmo-bsc-nat/bssap_conn.c

@ -18,6 +18,7 @@
*/
#include "config.h"
#include <errno.h>
#include <osmocom/core/msgb.h>
#include <osmocom/gsm/gsm0808.h>
#include <osmocom/sigtran/sccp_helpers.h>
@ -31,7 +32,7 @@ int bssmap_replace_ie_aoip_transp_addr(struct msgb **msg, struct sockaddr_storag
struct msgb *msg_old = *msg;
const struct tlv_definition *def = gsm0808_att_tlvdef();
int ofs = 1; /* first byte is bssmap message type */
int rc;
uint8_t tag;
msg_new = msgb_alloc_headroom(BSSMAP_MSG_SIZE, BSSMAP_MSG_HEADROOM, talloc_get_name(msg_old));
OSMO_ASSERT(msg_new);
@ -39,26 +40,25 @@ int bssmap_replace_ie_aoip_transp_addr(struct msgb **msg, struct sockaddr_storag
while (ofs < msgb_l3len(msg_old)) {
int rv;
uint8_t tag;
const uint8_t *val;
uint16_t len;
const uint8_t len_tl = 2;
uint16_t len_v;
rv = tlv_parse_one(&tag, &len, &val, def, &msg_old->l3h[ofs], msgb_l3len(msg_old) - ofs);
rv = tlv_parse_one(&tag, &len_v, &val, def, &msg_old->l3h[ofs], msgb_l3len(msg_old) - ofs);
if (rv < 0) {
LOGP(DMAIN, LOGL_ERROR, "Failed to parse bssmap msg\n");
msgb_free(msg_new);
return rv;
}
if (tag == GSM0808_IE_AOIP_TRASP_ADDR)
rc = gsm0808_enc_aoip_trasp_addr(msg_new, ss);
else
rc = tlv_encode_one(msg_new, def->def[tag].type, tag, len, val);
if (rc < 0) {
LOGP(DMAIN, LOGL_ERROR, "Failed to encode tag %d into copy of bssmap msg\n", tag);
msgb_free(msg_new);
return rc;
if (tag == GSM0808_IE_AOIP_TRASP_ADDR) {
if (gsm0808_enc_aoip_trasp_addr(msg_new, ss) == 0)
goto enc_err;
} else {
if (len_tl + len_v > msgb_tailroom(msg_new))
goto enc_err;
if (tlv_encode_one(msg_new, def->def[tag].type, tag, len_v, val) < 0)
goto enc_err;
}
ofs += rv;
@ -68,6 +68,10 @@ int bssmap_replace_ie_aoip_transp_addr(struct msgb **msg, struct sockaddr_storag
msgb_free(msg_old);
*msg = msg_new;
return 0;
enc_err:
LOGP(DMAIN, LOGL_ERROR, "Failed to encode tag %d into copy of bssmap msg\n", tag);
msgb_free(msg_new);
return -EINVAL;
}
int bssmap_tx_assignment_failure(enum bsc_nat_net net, struct subscr_conn *subscr_conn, enum gsm0808_cause cause)

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