ipa: Handle corrupt incoming messages without crashing
Attempt to read the three byte IPA header. If we read 0 then
the socket can be closed otherwise we need to read three bytes, if
we don't we do have a failure.
After having parsed the header we need to evaluate the length,
if the length is bigger than would fit into our buffer we will
ignore that and print an error.
This is fixing a crash when the BTS is crashing...
diff --git a/openbsc/src/input/ipaccess.c b/openbsc/src/input/ipaccess.c
index 91d267c..3e26689 100644
--- a/openbsc/src/input/ipaccess.c
+++ b/openbsc/src/input/ipaccess.c
@@ -289,14 +289,14 @@
/* first read our 3-byte header */
hh = (struct ipaccess_head *) msg->data;
- ret = recv(bfd->fd, msg->data, 3, 0);
- if (ret < 0) {
- if (errno != EAGAIN)
- LOGP(DINP, LOGL_ERROR, "recv error %d %s\n", ret, strerror(errno));
+ ret = recv(bfd->fd, msg->data, sizeof(*hh), 0);
+ if (ret == 0) {
msgb_free(msg);
*error = ret;
return NULL;
- } else if (ret == 0) {
+ } else if (ret != sizeof(*hh)) {
+ if (errno != EAGAIN)
+ LOGP(DINP, LOGL_ERROR, "recv error %d %s\n", ret, strerror(errno));
msgb_free(msg);
*error = ret;
return NULL;
@@ -307,9 +307,17 @@
/* then read te length as specified in header */
msg->l2h = msg->data + sizeof(*hh);
len = ntohs(hh->len);
+
+ if (len < 0 || TS1_ALLOC_SIZE < len + sizeof(*hh)) {
+ LOGP(DINP, LOGL_ERROR, "Can not read this packet. %d avail\n", len);
+ msgb_free(msg);
+ *error = -EIO;
+ return NULL;
+ }
+
ret = recv(bfd->fd, msg->l2h, len, 0);
if (ret < len) {
- LOGP(DINP, LOGL_ERROR, "short read!\n");
+ LOGP(DINP, LOGL_ERROR, "short read! Got %d from %d\n", ret, len);
msgb_free(msg);
*error = -EIO;
return NULL;