From 19b53e264527a1506a21e7b563c47500ac304450 Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Tue, 1 May 2018 19:34:21 -0400
Subject: [PATCH] Use a deterministic PRNG in test_circuit_timeout()
I'd prefer not to do this for randomized tests, but as things stand
with this test, it produces nondeterministic test coverage.
Closes ticket 25995; bugfix on 0.2.2.2-alpha when this test was
introduced.
---
changes/ticket25995 | 5 +++++
src/test/test.c | 19 +++++++++++++++++++
2 files changed, 24 insertions(+)
create mode 100644 changes/ticket25995
diff --git a/changes/ticket25995 b/changes/ticket25995
new file mode 100644
index 0000000000..855020bd39
--- /dev/null
+++ b/changes/ticket25995
@@ -0,0 +1,5 @@
+ o Minor bugfixes (tests):
+ - While running the circuit_timeout test, fix the PRNG to a deterministic
+ AES stream, so that the test coverage from this test will itself be
+ deterministic. Fixes bug 25995; bugfix on 0.2.2.2-alpha.
+
diff --git a/src/test/test.c b/src/test/test.c
index 2963f169cf..3c6e0a45ee 100644
--- a/src/test/test.c
+++ b/src/test/test.c
@@ -349,6 +349,18 @@ test_onion_queues(void *arg)
tor_free(onionskin);
}
+static crypto_cipher_t *crypto_rand_aes_cipher = NULL;
+
+// Mock replacement for crypto_rand: Generates bytes from a provided AES_CTR
+// cipher in <b>crypto_rand_aes_cipher</b>.
+static void
+crypto_rand_deterministic_aes(char *out, size_t n)
+{
+ tor_assert(crypto_rand_aes_cipher);
+ memset(out, 0, n);
+ crypto_cipher_crypt_inplace(crypto_rand_aes_cipher, out, n);
+}
+
static void
test_circuit_timeout(void *arg)
{
@@ -378,6 +390,11 @@ test_circuit_timeout(void *arg)
state = or_state_new();
+ // Use a deterministic RNG here, or else we'll get nondeterministic
+ // coverage in some of the circuitstats functions.
+ MOCK(crypto_rand, crypto_rand_deterministic_aes);
+ crypto_rand_aes_cipher = crypto_cipher_new("xyzzyplughplover");
+
circuitbuild_running_unit_tests();
#define timeout0 (build_time_t)(30*1000.0)
initial.Xm = 3000;
@@ -512,6 +529,8 @@ test_circuit_timeout(void *arg)
circuit_build_times_free_timeouts(&final);
or_state_free(state);
teardown_periodic_events();
+ UNMOCK(crypto_rand);
+ crypto_cipher_free(crypto_rand_aes_cipher);
}
/** Test encoding and parsing of rendezvous service descriptors. */
--
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