On 17/06/16 20:56, Matt Caswell via RT wrote:
>
>
> On 17/06/16 19:43, Mick Saxton via RT wrote:
>> Perhaps we should consider if there are any negative consequences to my
>> solution?
>> It does work.
>>
>> I am trying really hard to get contention but I am only seeing this problem
>> in about 1 out of 100,000 successful TLSv1.2 connections
>> On a heavily congested network.
>> I require three machines to just to run the test that causes the failure.
>>
>> All we are trying to do is get a random number – surely getting a slightly
>> less random number is better than crashing?
>> It could be that the problematic instances were going to disconnect anyway
>> due to TCP/IP problems.
>>
>
> I think we need to try instrumenting the code to see if we can get some
> more information out. I will try and pull something together - but it
> might be Monday before I get the opportunity.
I got to it quicker than I thought. Please see attached patch. Can you
apply it to the latest git 1.0.2 version and re-run your test (capture
stderr output). I'd like to see what we get.
Also is this 32-bit or 64-bit Windows? Are you able to share your
locking callback implementation?
Thanks
Matt
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Ticket here: http://rt.openssl.org/Ticket/Display.html?id=4545
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>From 71bec261502b5ad7ad3bb8ad39b069c49d42da5f Mon Sep 17 00:00:00 2001
From: Matt Caswell <m...@openssl.org>
Date: Fri, 17 Jun 2016 23:57:13 +0100
Subject: [PATCH] Add some instrumentation to md_rand.c
---
crypto/rand/md_rand.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/crypto/rand/md_rand.c b/crypto/rand/md_rand.c
index bd76e23..7c2931e 100644
--- a/crypto/rand/md_rand.c
+++ b/crypto/rand/md_rand.c
@@ -270,6 +270,19 @@ static void ssleay_rand_add(const void *buf, int num, double add)
MD_Update(&m, local_md, MD_DIGEST_LENGTH);
k = (st_idx + j) - STATE_SIZE;
if (k > 0) {
+ if (j - k < 0) {
+ CRYPTO_THREADID thisthreadid;
+ CRYPTO_THREADID_current(&thisthreadid);
+ fprintf(stderr, "MD_RAND ERROR: ssleay_rand_add: k == %d, "
+ "j == %d, st_idx == %d, state_num == %ld, do_not_lock %d, "
+ "crypto_lock_rand == %d, locking_threadid == %lu, "
+ "thisthreadid == %lu\n",
+ k, j, st_idx, state_num, do_not_lock, crypto_lock_rand,
+ CRYPTO_THREADID_hash(&locking_threadid),
+ CRYPTO_THREADID_hash(&thisthreadid));
+ fflush(stderr);
+ abort();
+ }
MD_Update(&m, &(state[st_idx]), j - k);
MD_Update(&m, &(state[0]), k);
} else
@@ -492,6 +505,19 @@ int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo, int lock)
k = (st_idx + MD_DIGEST_LENGTH / 2) - st_num;
if (k > 0) {
+ if (MD_DIGEST_LENGTH / 2 - k < 0) {
+ CRYPTO_THREADID thisthreadid;
+ CRYPTO_THREADID_current(&thisthreadid);
+ fprintf(stderr, "MD_RAND ERROR: ssleay_rand_bytes: k == %d, "
+ "st_idx == %ld, st_num == %ld, lock %d, "
+ "crypto_lock_rand == %d, locking_threadid == %lu, "
+ "thisthreadid == %lu\n",
+ k, st_idx, st_num, lock, crypto_lock_rand,
+ CRYPTO_THREADID_hash(&locking_threadid),
+ CRYPTO_THREADID_hash(&thisthreadid));
+ fflush(stderr);
+ abort();
+ }
MD_Update(&m, &(state[st_idx]), MD_DIGEST_LENGTH / 2 - k);
MD_Update(&m, &(state[0]), k);
} else
--
2.7.4
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