<p>Vadim Yanitskiy has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/13490">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">libmsc/db.c: properly get / set TP-UD length (octets vs septets)<br><br>According to 3GPP TS 03.40, section 9.2.3.16, the TP-UDL field<br>indicates the length of TP-UD (User-Data, including TP-UDH)<br>either in septets, or in octets, depending on DSC in use.<br><br>When retrieving the TP-UD from the database, we get the length<br>in octets (bytes), regardless of the DCS value. Before this<br>patch, it was merely copied to struct 'gsm_sms', without<br>any conversion from octets to septets.<br><br>The same problem was in db_sms_store(), which could run into<br>a buffer overflow, using the amount of septets (e.g. 160) to<br>store some 8-bit or UCS-2 encoded data (up to 140 octets).<br><br>Change-Id: I84f973bc6561a9822b4b26975a781abd2b6e026a<br>---<br>M src/libmsc/db.c<br>1 file changed, 25 insertions(+), 3 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/osmo-msc refs/changes/90/13490/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/src/libmsc/db.c b/src/libmsc/db.c</span><br><span>index 6cd8493..f48384e 100644</span><br><span>--- a/src/libmsc/db.c</span><br><span>+++ b/src/libmsc/db.c</span><br><span>@@ -38,6 +38,7 @@</span><br><span> #include <osmocom/msc/vlr.h></span><br><span> </span><br><span> #include <osmocom/gsm/protocol/gsm_23_003.h></span><br><span style="color: hsl(120, 100%, 40%);">+#include <osmocom/gsm/gsm0411_utils.h></span><br><span> #include <osmocom/core/talloc.h></span><br><span> #include <osmocom/core/statistics.h></span><br><span> #include <osmocom/core/rate_ctr.h></span><br><span>@@ -227,6 +228,7 @@</span><br><span> </span><br><span> static void parse_tp_ud_from_result(struct gsm_sms *sms, dbi_result result)</span><br><span> {</span><br><span style="color: hsl(120, 100%, 40%);">+ enum sms_alphabet dcs_alphabet;</span><br><span> const unsigned char *user_data;</span><br><span> unsigned int user_data_len;</span><br><span> unsigned int text_len;</span><br><span>@@ -240,12 +242,20 @@</span><br><span> user_data_len, sizeof(sms->user_data));</span><br><span> user_data_len = (uint8_t) sizeof(sms->user_data);</span><br><span> }</span><br><span style="color: hsl(0, 100%, 40%);">- sms->user_data_len = user_data_len;</span><br><span> </span><br><span> /* Retrieve the TP-UD (User-Data) itself */</span><br><span> user_data = dbi_result_get_binary(result, "user_data");</span><br><span> memcpy(sms->user_data, user_data, user_data_len);</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ /* We may need to convert the length in octets to a value in septets,</span><br><span style="color: hsl(120, 100%, 40%);">+ * if 7-bit default alphabet is used (see 3GPP TS 03.40,</span><br><span style="color: hsl(120, 100%, 40%);">+ * section 9.2.3.16 for details). */</span><br><span style="color: hsl(120, 100%, 40%);">+ dcs_alphabet = gsm338_get_sms_alphabet(sms->data_coding_scheme);</span><br><span style="color: hsl(120, 100%, 40%);">+ if (dcs_alphabet == DCS_7BIT_DEFAULT)</span><br><span style="color: hsl(120, 100%, 40%);">+ sms->user_data_len = user_data_len * 8 / 7;</span><br><span style="color: hsl(120, 100%, 40%);">+ else</span><br><span style="color: hsl(120, 100%, 40%);">+ sms->user_data_len = user_data_len;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /* Retrieve the text length (excluding '\0') */</span><br><span> text_len = dbi_result_get_field_length(result, "text");</span><br><span> if (text_len >= sizeof(sms->text)) {</span><br><span>@@ -716,12 +726,24 @@</span><br><span> char *q_text, *q_daddr, *q_saddr;</span><br><span> unsigned char *q_udata;</span><br><span> time_t now, validity_timestamp;</span><br><span style="color: hsl(120, 100%, 40%);">+ enum sms_alphabet dcs_alphabet;</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int user_data_len;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* We may need to convert the length in septets to a value in octets,</span><br><span style="color: hsl(120, 100%, 40%);">+ * if 7-bit default alphabet is used (see 3GPP TS 03.40,</span><br><span style="color: hsl(120, 100%, 40%);">+ * section 9.2.3.16 for details). */</span><br><span style="color: hsl(120, 100%, 40%);">+ dcs_alphabet = gsm338_get_sms_alphabet(sms->data_coding_scheme);</span><br><span style="color: hsl(120, 100%, 40%);">+ if (dcs_alphabet == DCS_7BIT_DEFAULT) {</span><br><span style="color: hsl(120, 100%, 40%);">+ user_data_len = sms->user_data_len * 7 / 8;</span><br><span style="color: hsl(120, 100%, 40%);">+ if (sms->user_data_len * 7 % 8 != 0)</span><br><span style="color: hsl(120, 100%, 40%);">+ user_data_len++;</span><br><span style="color: hsl(120, 100%, 40%);">+ } else</span><br><span style="color: hsl(120, 100%, 40%);">+ user_data_len = sms->user_data_len;</span><br><span> </span><br><span> dbi_conn_quote_string_copy(conn, (char *)sms->text, &q_text);</span><br><span> dbi_conn_quote_string_copy(conn, (char *)sms->dst.addr, &q_daddr);</span><br><span> dbi_conn_quote_string_copy(conn, (char *)sms->src.addr, &q_saddr);</span><br><span style="color: hsl(0, 100%, 40%);">- dbi_conn_quote_binary_copy(conn, sms->user_data, sms->user_data_len,</span><br><span style="color: hsl(0, 100%, 40%);">- &q_udata);</span><br><span style="color: hsl(120, 100%, 40%);">+ dbi_conn_quote_binary_copy(conn, sms->user_data, user_data_len, &q_udata);</span><br><span> </span><br><span> now = time(NULL);</span><br><span> validity_timestamp = now + sms->validity_minutes * 60;</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/13490">change 13490</a>. 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<div style="display:none"> Gerrit-Project: osmo-msc </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>
<div style="display:none"> Gerrit-Change-Id: I84f973bc6561a9822b4b26975a781abd2b6e026a </div>
<div style="display:none"> Gerrit-Change-Number: 13490 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: Vadim Yanitskiy <axilirator@gmail.com> </div>