osmocom
/
wireshark
14
0
Fork 1
Code Issues Pull Requests Projects Releases Wiki Activity

Use format_text() when displaying, not when handing to AirPDcap. 

format_text() is specifically intended to handle strings when displaying
them to the user; code such as AirPDCap, which doesn't display strings
to the user, should be handed the raw SSID.

Put in a comment indicating what we probably *should* be doing here.

Bug: 11685

Change-Id: Ic30114c35d1d8f3d791ae904e33a4d81ddc215ec
Reviewed-on: https://code.wireshark.org/review/11757
Reviewed-by: Guy Harris <guy@alum.mit.edu>
This commit is contained in:
Guy Harris 2015-11-11 22:29:20 -08:00
parent 90d9710145
commit e240ad882b
1 changed files with 56 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

72
epan/dissectors/packet-ieee80211.c
View File

@ -13258,7 +13258,6 @@ ieee80211_tag_ssid(packet_info *pinfo, proto_tree *tree,
{
/* 7.3.2.1 SSID element (0) */
gchar *ssid; /* The SSID may consist of arbitrary bytes */
const gchar *ssid_end;
gint ssid_len = tag_len;
if (beacon_padding != 0) /* padding bug */
@ -13271,26 +13270,67 @@ ieee80211_tag_ssid(packet_info *pinfo, proto_tree *tree,
ssid_len = MAX_SSID_LEN;
}
ssid = format_text(tvb_get_string_enc(wmem_packet_scope(), tvb, offset + 2, ssid_len, ENC_ASCII), ssid_len);
/*
* XXX - the 802.11 specs aren't particularly clear on how the SSID
* is to be interpreted.
*
* IEEE Std 802.11-1999, section 7.3.2.2 "Service Set Identity (SSID)
* element" says just
*
* The length of the SSID information field is between 0 and 32
* octets. A 0 length information field indicates the broadcast SSID.
*
* with no indication that those octets encode a string.
*
* IEEE Std 802.11-2012, section 8.4.2.2 "SSID element", says that *but*
* says after it
*
* When the UTF-8 SSID subfield of the Extended Capabilities element
* is equal to 1 in the frame that includes the SSID element, the
* SSID is interpreted using UTF-8 encoding.
*
* NOTE -- This is true for Beacon and Probe Response frames when the
* MLME-START.request primitive was issued with the SSIDEncoding
* parameter equal to UTF8.
*
* and the SSIDEncoding parameter can either be UNSPECIFIED or UTF8.
*
* So I *guess* that means that, if the UTF-8 SSID subfield isn't
* equal to 1, the SSID is, in theory, just a bunch of octets, but
* in practice, *probably* ASCII as that's the typical convention,
* and, if it is equal to 1, it's a UTF-8 string. (Of course, a
* host can put anything there it wants to, so we shouldn't just
* assume that it's *valid* ASCII or *valid* UTF-8.)
*
* So we really should extract it as an array of ssid_len bytes,
* pass those bytes to AirPDcapSetLastSSID(), and:
*
* If the UTF-8 SSID subfield isn't set to 1, put the SSID in
* as an ENC_ASCII string;
*
* If the UTF-8 SSID subfield is set to 1, put it in as an
* ENC_UTF_8 string;
*
* and rely on the libwireshark core code to somehow deal with
* non-ASCII characters or invalid UTF-8 sequences or valid-but-
* not-all-printable ASCII or UTF-8 strings in the protocol tree
* display. I'm not sure we can currently rely on it to handle
* invalid UTF-8 or non-printable characters in UTF-8 strings,
* however, so we just treat it as ASCII for now.
*
* We also need a better way of getting the display format of a
* string value, so we can do something other than run it through
* format_text(), which won't handle UTF-8.
*/
ssid = tvb_get_string_enc(wmem_packet_scope(), tvb, offset + 2, ssid_len, ENC_ASCII);
if (ssid_len == (gint)tag_len) {
AirPDcapSetLastSSID(&airpdcap_ctx, (CHAR *) ssid, ssid_len);
}
g_utf8_validate(ssid, ssid_len, &ssid_end);
ssid[ssid_end - ssid] = '\0';
if ((gint)(ssid_end - ssid) == ssid_len) {
proto_tree_add_item(tree, hf_ieee80211_tag_ssid, tvb, offset + 2, tag_len,
ENC_ASCII|ENC_NA);
} else {
wmem_strbuf_t *ssid_sb = wmem_strbuf_new(wmem_packet_scope(), ssid);
ssid_len = (gint)(ssid_end - ssid);
wmem_strbuf_append(ssid_sb, " [truncated]");
proto_tree_add_string_format_value(tree, hf_ieee80211_tag_ssid, tvb, offset + 2, tag_len,
ssid, "%s", wmem_strbuf_get_str(ssid_sb));
ssid = (gchar*)wmem_strbuf_get_str(ssid_sb);
}
proto_tree_add_item(tree, hf_ieee80211_tag_ssid, tvb, offset + 2, tag_len,
ENC_ASCII|ENC_NA);
if (ssid_len > 0) {
proto_item_append_text(ti, ": %s", ssid);
proto_item_append_text(ti, ": %s", format_text(ssid, ssid_len));
col_append_fstr(pinfo->cinfo, COL_INFO, ", SSID=%s", format_text(ssid, ssid_len));