From 76ecd85c2cf4b9b1fb2350774d24860537d1d571 Mon Sep 17 00:00:00 2001
From: Mark Haines <mark.haines@matrix.org>
Date: Fri, 7 Aug 2015 18:25:21 +0100
Subject: Fix a crash when decoding messages that are too short
---
src/message.cpp | 3 ++
tests/test_olm_decrypt.cpp | 69 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+)
create mode 100644 tests/test_olm_decrypt.cpp
diff --git a/src/message.cpp b/src/message.cpp
index 93473b9..8e807fd 100644
--- a/src/message.cpp
+++ b/src/message.cpp
@@ -49,6 +49,9 @@ T varint_decode(
std::uint8_t const * varint_end
) {
T value = 0;
+ if (varint_end == varint_start) {
+ return 0;
+ }
do {
value <<= 7;
value |= 0x7F & *(--varint_end);
diff --git a/tests/test_olm_decrypt.cpp b/tests/test_olm_decrypt.cpp
new file mode 100644
index 0000000..f089665
--- /dev/null
+++ b/tests/test_olm_decrypt.cpp
@@ -0,0 +1,69 @@
+#include "olm/olm.hh"
+#include "unittest.hh"
+
+const char * test_cases[] = {
+ "41776f",
+ "7fff6f0101346d671201"
+};
+
+
+const char * session_data =
+ "E0p44KO2y2pzp9FIjv0rud2wIvWDi2dx367kP4Fz/9JCMrH+aG369HGymkFtk0+PINTLB9lQRt"
+ "ohea5d7G/UXQx3r5y4IWuyh1xaRnojEZQ9a5HRZSNtvmZ9NY1f1gutYa4UtcZcbvczN8b/5Bqg"
+ "e16cPUH1v62JKLlhoAJwRkH1wU6fbyOudERg5gdXA971btR+Q2V8GKbVbO5fGKL5phmEPVXyMs"
+ "rfjLdzQrgjOTxN8Pf6iuP+WFPvfnR9lDmNCFxJUVAdLIMnLuAdxf1TGcS+zzCzEE8btIZ99mHF"
+ "dGvPXeH8qLeNZA";
+
+void decode_hex(
+ const char * input,
+ std::uint8_t * output, std::size_t output_length
+) {
+ std::uint8_t * end = output + output_length;
+ while (output != end) {
+ char high = *(input++);
+ char low = *(input++);
+ if (high >= 'a') high -= 'a' - ('9' + 1);
+ if (low >= 'a') low -= 'a' - ('9' + 1);
+ uint8_t value = ((high - '0') << 4) | (low - '0');
+ *(output++) = value;
+ }
+}
+
+void decrypt_case(int message_type, const char * test_case) {
+ std::uint8_t session_memory[olm_session_size()];
+ ::OlmSession * session = ::olm_session(session_memory);
+
+ std::uint8_t pickled[strlen(session_data)];
+ ::memcpy(pickled, session_data, sizeof(pickled));
+ ::olm_unpickle_session(session, "", 0, pickled, sizeof(pickled));
+
+ std::size_t message_length = strlen(test_case) / 2;
+ std::uint8_t message[message_length];
+ decode_hex(test_case, message, message_length);
+
+ size_t max_length = olm_decrypt_max_plaintext_length(
+ session, message_type, message, message_length
+ );
+
+ if (max_length == std::size_t(-1)) return;
+
+ uint8_t plaintext[max_length];
+ decode_hex(test_case, message, message_length);
+ olm_decrypt(
+ session, message_type,
+ message, message_length,
+ plaintext, max_length
+ );
+}
+
+
+int main() {
+{
+TestCase("Olm decrypt test");
+
+for (int i = 0; i < sizeof(test_cases)/ sizeof(const char *); ++i) {
+ decrypt_case(0, test_cases[i]);
+}
+
+}
+}
--
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