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authorAnders Svensson <[email protected]>2015-06-15 17:46:44 +0200
committerAnders Svensson <[email protected]>2015-06-18 00:41:37 +0200
commit7f4f9583bb1245c27ca58d88fe6862498a2df1f2 (patch)
tree59d0c6e4632a54f96cf6b6f7202cb3cd5eb26aaf /lib/diameter/include/diameter_gen.hrl
parent552962544c812caa1005094f3a0a00e05556565b (diff)
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Fix decode of Grouped AVPs containing errors
RFC 6733 says this of Failed-AVP in 7.5: In the case where the offending AVP is embedded within a Grouped AVP, the Failed-AVP MAY contain the grouped AVP, which in turn contains the single offending AVP. The same method MAY be employed if the grouped AVP itself is embedded in yet another grouped AVP and so on. In this case, the Failed-AVP MAY contain the grouped AVP hierarchy up to the single offending AVP. This enables the recipient to detect the location of the offending AVP when embedded in a group. It says this of DIAMETER_INVALID_AVP_LENGTH in 7.1.5: The request contained an AVP with an invalid length. A Diameter message indicating this error MUST include the offending AVPs within a Failed-AVP AVP. In cases where the erroneous AVP length value exceeds the message length or is less than the minimum AVP header length, it is sufficient to include the offending AVP header and a zero filled payload of the minimum required length for the payloads data type. If the AVP is a Grouped AVP, the Grouped AVP header with an empty payload would be sufficient to indicate the offending AVP. In the case where the offending AVP header cannot be fully decoded when the AVP length is less than the minimum AVP header length, it is sufficient to include an offending AVP header that is formulated by padding the incomplete AVP header with zero up to the minimum AVP header length. The AVPs placed in the errors field of a diameter_packet record are intended to be appropriate for inclusion in a Failed-AVP, but neither of the above paragraphs has been followed in the Grouped case: the entire faulty AVP (non-faulty components and all) has been included. This made it impossible to identify the actual faulty AVP in all but simple case. This commit adapts the decode to the RFC, and implements the suggested single faulty AVP, nested in as many Grouped containers as required. The best-effort decode of Failed-AVP in answer messages, initially implemented in commit 0f9cdbaf, is also applied.
Diffstat (limited to 'lib/diameter/include/diameter_gen.hrl')
-rw-r--r--lib/diameter/include/diameter_gen.hrl61
1 files changed, 49 insertions, 12 deletions
diff --git a/lib/diameter/include/diameter_gen.hrl b/lib/diameter/include/diameter_gen.hrl
index 81e093b91a..fb321054bd 100644
--- a/lib/diameter/include/diameter_gen.hrl
+++ b/lib/diameter/include/diameter_gen.hrl
@@ -333,10 +333,8 @@ d(Name, Avp, Acc) ->
{H, A} = ungroup(V, Avp),
{[H | Avps], pack_avp(Name, A, T)}
catch
- throw: {?TAG, {grouped, RC, ComponentAvps}} ->
- {Avps, {Rec, Errors}} = Acc,
- A = trim(Avp),
- {[[A | trim(ComponentAvps)] | Avps], {Rec, [{RC, A} | Errors]}};
+ throw: {?TAG, {grouped, Error, ComponentAvps}} ->
+ g(is_failed(), Error, Name, trim(Avp), Acc, ComponentAvps);
error: Reason ->
d(is_failed(), Reason, Name, trim(Avp), Acc)
after
@@ -376,6 +374,27 @@ dict(true) ->
dict(_) ->
?MODULE.
+%% g/5
+
+%% Ignore decode errors within Failed-AVP (best-effort) ...
+g(true, [_Error | Rec], Name, Avp, Acc, _ComponentAvps) ->
+ decode_AVP(Name, Avp#diameter_avp{value = Rec}, Acc);
+g(true, _Error, Name, Avp, Acc, _ComponentAvps) ->
+ decode_AVP(Name, Avp, Acc);
+
+%% ... or not.
+g(false, [Error | _Rec], _Name, Avp, Acc, ComponentAvps) ->
+ g(Error, Avp, Acc, ComponentAvps);
+g(false, Error, _Name, Avp, Acc, ComponentAvps) ->
+ g(Error, Avp, Acc, ComponentAvps).
+
+%% g/4
+
+g({RC, ErrorData}, Avp, Acc, ComponentAvps) ->
+ {Avps, {Rec, Errors}} = Acc,
+ E = Avp#diameter_avp{data = [ErrorData]},
+ {[[Avp | trim(ComponentAvps)] | Avps], {Rec, [{RC, E} | Errors]}}.
+
%% d/5
%% Ignore a decode error within Failed-AVP ...
@@ -459,8 +478,8 @@ decode_AVP(Name, Avp, {Avps, Acc}) ->
%% diameter_types will raise an error of this form to communicate
%% DIAMETER_INVALID_AVP_LENGTH (5014). A module specified to a
-%% @custom_types tag in a spec file can also raise an error of this
-%% form.
+%% @custom_types tag in a dictionary file can also raise an error of
+%% this form.
rc({'DIAMETER', 5014 = RC, _}, #diameter_avp{name = AvpName} = Avp) ->
{RC, Avp#diameter_avp{data = empty_value(AvpName)}};
@@ -617,9 +636,12 @@ value(_, Avp) ->
-> binary()
| no_return().
-%% Length error induced by diameter_codec:collect_avps/1.
+%% Length error induced by diameter_codec:collect_avps/1: the AVP
+%% length in the header was too short (insufficient for the extracted
+%% header) or too long (past the end of the message). An empty payload
+%% is sufficient according to the RFC text for 5014.
grouped_avp(decode, _Name, <<0:1, _/binary>>) ->
- throw({?TAG, {grouped, 5014, []}});
+ throw({?TAG, {grouped, {5014, []}, []}});
grouped_avp(decode, Name, Data) ->
grouped_decode(Name, diameter_codec:collect_avps(Data));
@@ -633,13 +655,28 @@ grouped_avp(encode, Name, Data) ->
%% decoded value, also returning the list of component diameter_avp
%% records.
+%% Length error in trailing component AVP.
grouped_decode(_Name, {Error, Acc}) ->
- {RC, Avp} = Error,
- throw({?TAG, {grouped, RC, [Avp | Acc]}});
-
+ {5014, Avp} = Error,
+ throw({?TAG, {grouped, Error, [Avp | Acc]}});
+
+%% 7.5. Failed-AVP AVP
+
+%% In the case where the offending AVP is embedded within a Grouped AVP,
+%% the Failed-AVP MAY contain the grouped AVP, which in turn contains
+%% the single offending AVP. The same method MAY be employed if the
+%% grouped AVP itself is embedded in yet another grouped AVP and so on.
+%% In this case, the Failed-AVP MAY contain the grouped AVP hierarchy up
+%% to the single offending AVP. This enables the recipient to detect
+%% the location of the offending AVP when embedded in a group.
+
+%% An error in decoding a component AVP throws the first fauly
+%% component, which the catch in d/3 wraps in the Grouped AVP in
+%% question. A partially decoded record is only used when ignoring
+%% errors in Failed-AVP.
grouped_decode(Name, ComponentAvps) ->
{Rec, Avps, Es} = decode_avps(Name, ComponentAvps),
- [] == Es orelse throw({?TAG, {grouped, 5004, Avps}}), %% decode failure
+ [] == Es orelse throw({?TAG, {grouped, [{_,_} = hd(Es) | Rec], Avps}}),
{Rec, Avps}.
%% ---------------------------------------------------------------------------