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authorPau Espin Pedrol <pespin@sysmocom.de>2019-03-27 17:33:17 +0100
committerPau Espin Pedrol <pespin@sysmocom.de>2019-03-28 12:22:36 +0000
commitdeeab473a030cdb68f7a258b0f6629444933ac1e (patch)
treee66e29b0cfc9daf0a65ab7f7fee5c1cbea1f663c /src/gsm
parentb9baf02c1227f3ed1791332514ed8c34a468ffe5 (diff)
ipa: Document ipa_ccm_idtag_parse_off and fix ipa_ccm_idtag_parse
ipa_ccm_idtag_parse_off is broken, and can only be used with len_offset=1 on ID Request messages, otherwise won't work correctly. Modify ipa_ccm_idtag_parse to at least parse those correctly, and document the limitations. Those two functions are already deprecated and only used in openbsc by 3 callers: * ipa_ccm_idtag_parse in ussd_read_cb(): Broken, that function can only work for Requests and it's used to parse a Response. * ipa_ccm_idtag_parse_off in forward_sccp_to_msc (NAT): Broken, it can only be used to parse Requests and it's used to parse a Response. Furthermore, len_offset=2 is passed which makes no sense and most probably it fails always, or can even make the program crash. * ipa_ccm_idtag_parse_off in (answer_challenge): This one is fine and could actually be replaced with ipa_ccm_id_get_parse after this commit is merged. Change-Id: I6efc852dfc041192f554e41a58290a0f63298021
Diffstat (limited to 'src/gsm')
-rw-r--r--src/gsm/ipa.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/src/gsm/ipa.c b/src/gsm/ipa.c
index d423c262..8e64a1eb 100644
--- a/src/gsm/ipa.c
+++ b/src/gsm/ipa.c
@@ -98,11 +98,21 @@ const char *ipa_ccm_idtag_name(uint8_t tag)
return idtag_names[tag];
}
+/*! Parse the payload part of an IPA CCM ID GET, return \ref tlv_parsed format. */
int ipa_ccm_idtag_parse(struct tlv_parsed *dec, unsigned char *buf, int len)
{
- return ipa_ccm_idtag_parse_off(dec, buf, len, 0);
+ return ipa_ccm_idtag_parse_off(dec, buf, len, 1);
}
+/*! Parse the payload part of an IPA CCM ID GET, return \ref tlv_parsed format.
+ * WARNING: This function can only parse correctly IPA CCM ID GET/REQUEST
+ * messages, and only when len_offset is passed value of 1.
+ * \param[out] dec Caller-provided/allocated output structure for parsed payload
+ * \param[in] buf Buffer containing the payload (excluding 1 byte msg_type) of the message
+ * \param[in] len Length of \a buf in octets
+ * \param[in] len_offset Offset from end of len field to start of value (ommiting tag). Must be 1!
+ * \returns 0 on success; negative on error
+ */
int ipa_ccm_idtag_parse_off(struct tlv_parsed *dec, unsigned char *buf, int len, const int len_offset)
{
uint8_t t_len;