[PATCH 2/3] smpp_smsc: Check that the size is large enough to hold actual data

From: Daniel Willmann &lt;dwillmann(a)sysmocom.de&gt; The first 4 bytes are the length including the length field. For length < 4 the subsequent msgb_put(msg, sizeof(uint32_t)) will fail, resulting in an abort. The code also expects (in smpp_msgb_cmdid()) the existence of 4 more bytes for the SMPP command ID. This patch checks that the length received is large enough to hold all 8 bytes in the msgb and drops the connection if that's not the case. The issue is reproducible with: echo -e "\x00\x00\x00\x02\x00" |socat stdin tcp:localhost:2775 --- openbsc/src/libmsc/smpp_smsc.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/openbsc/src/libmsc/smpp_smsc.c b/openbsc/src/libmsc/smpp_smsc.c index 1e9829b..605bdd5 100644 --- a/openbsc/src/libmsc/smpp_smsc.c +++ b/openbsc/src/libmsc/smpp_smsc.c @@ -803,6 +803,12 @@ static int esme_link_read_cb(struct osmo_fd *ofd) if (esme->read_idx >= sizeof(uint32_t)) { esme->read_len = ntohl(len); + if (esme->read_len < 8) { + LOGP(DSMPP, LOGL_ERROR, "[%s] read length too small %u\n", + esme->system_id, esme->read_len); + goto dead_socket; + } + msg = msgb_alloc(esme->read_len, "SMPP Rx"); if (!msg) return -ENOMEM; -- 1.8.4.2