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Code Issues Releases Wiki Activity

Fix a buffer bounds check when decoding group messages 

Fixes a segfault when a group message had exactly the length of the mac +
signature.

Also tweak skipping of unknown tags to avoid an extra trip around the loop.
rav/inter_device_key_shares
Richard van der Hoff 2016-10-19 15:03:40 +01:00
parent 38acc352a3
commit 1ff64391ed
1 changed files with 7 additions and 4 deletions
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11
src/message.cpp
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@ -214,11 +214,13 @@ void olm::decode_message(
reader.ciphertext = nullptr;
reader.ciphertext_length = 0;
if (pos == end) return;
if (input_length < mac_length) return;
if (pos == end) return;
reader.version = *(pos++);
while (pos != end) {
unknown = pos;
pos = decode(
pos, end, RATCHET_KEY_TAG,
reader.ratchet_key, reader.ratchet_key_length
@ -234,7 +236,6 @@ void olm::decode_message(
if (unknown == pos) {
pos = skip_unknown(pos, end);
}
unknown = pos;
}
}
@ -303,6 +304,7 @@ void olm::decode_one_time_key_message(
reader.version = *(pos++);
while (pos != end) {
unknown = pos;
pos = decode(
pos, end, ONE_TIME_KEY_ID_TAG,
reader.one_time_key, reader.one_time_key_length
@ -322,7 +324,6 @@ void olm::decode_one_time_key_message(
if (unknown == pos) {
pos = skip_unknown(pos, end);
}
unknown = pos;
}
}
@ -377,9 +378,12 @@ void _olm_decode_group_message(
results->ciphertext_length = 0;
if (input_length < trailer_length) return;
if (pos == end) return;
results->version = *(pos++);
while (pos != end) {
unknown = pos;
pos = decode(
pos, end, GROUP_MESSAGE_INDEX_TAG,
results->message_index, has_message_index
@ -391,7 +395,6 @@ void _olm_decode_group_message(
if (unknown == pos) {
pos = skip_unknown(pos, end);
}
unknown = pos;
}
results->has_message_index = (int)has_message_index;