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r19004@catbus: nickm | 2008-03-21 15:18:43 -0400
Use RAND_poll() again: the bug that made us stop using it has been fixed. svn:r14150
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@ -24,6 +24,13 @@ Changes in version 0.2.1.1-alpha - 2008-??-??
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- Add a couple of extra warnings to --enable-gcc-warnings for GCC 4.3,
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and stop using a warning that had become unfixably verbose under GCC
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4.3.
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- Start using OpenSSL's RAND_poll() for better (and more portable)
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cross-platform entropy collection again. We used to use it, then
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stopped using it because of a bug that could crash systems that called
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RAND_poll when they had a lot of fds open. It looks like the bug got
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fixed in late 2006. Our new behavior is to call RAND_poll() at
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startup, and to call RAND_poll() when we reseed later only if we
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have a non-buggy OpenSSL version.
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o Code simplifications and refactoring:
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- Refactor code using connection_ap_handshake_attach_circuit() to
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@ -1667,19 +1667,29 @@ crypto_dh_free(crypto_dh_env_t *dh)
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/* Use RAND_poll if openssl is 0.9.6 release or later. (The "f" means
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"release".) */
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//#define USE_RAND_POLL (OPENSSL_VERSION_NUMBER >= 0x0090600fl)
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#define USE_RAND_POLL 0
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/* XXX Somehow setting USE_RAND_POLL on causes stack smashes. We're
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* not sure where. This was the big bug with Tor 0.1.1.9-alpha. */
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#define HAVE_RAND_POLL (OPENSSL_VERSION_NUMBER >= 0x0090600fl)
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/** Seed OpenSSL's random number generator with bytes from the
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* operating system. Return 0 on success, -1 on failure.
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/* Versions of openssl prior to 0.9.7k and 0.9.8c had a bug where RAND_poll
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* would allocate an fd_set on the stack, open a new file, and try to FD_SET
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* that fd without checking whether it fit in the fd_set. Thus, if the
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* system has not just been started up, it is unsafe to call */
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#define RAND_POLL_IS_SAFE \
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((OPENSSL_VERSION_NUMBER >= 0x009070afl && \
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OPENSSL_VERSION_NUMBER <= 0x00907fffl) || \
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(OPENSSL_VERSION_NUMBER >= 0x0090803fl))
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/* We could actually get away with calling RAND_poll */
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#define USE_RAND_POLL (HAVE_RAND_POLL && RAND_POLL_IS_SAFE)
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/** Seed OpenSSL's random number generator with bytes from the operating
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* system. <b>startup</b> should be true iff we have just started Tor and
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* have not yet allocated a bunch of fds. Return 0 on success, -1 on failure.
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*/
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int
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crypto_seed_rng(void)
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crypto_seed_rng(int startup)
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{
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char buf[ADD_ENTROPY];
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int rand_poll_status;
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int rand_poll_status = 0;
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/* local variables */
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#ifdef MS_WINDOWS
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@ -1693,15 +1703,15 @@ crypto_seed_rng(void)
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size_t n;
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#endif
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#if USE_RAND_POLL
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#if HAVE_RAND_POLL
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/* OpenSSL 0.9.6 adds a RAND_poll function that knows about more kinds of
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* entropy than we do. We'll try calling that, *and* calling our own entropy
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* functions. If one succeeds, we'll accept the RNG as seeded. */
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rand_poll_status = RAND_poll();
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if (rand_poll_status == 0)
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log_warn(LD_CRYPTO, "RAND_poll() failed.");
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#else
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rand_poll_status = 0;
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if (startup || RAND_POLL_IS_SAFE) {
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rand_poll_status = RAND_poll();
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if (rand_poll_status == 0)
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log_warn(LD_CRYPTO, "RAND_poll() failed.");
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}
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#endif
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#ifdef MS_WINDOWS
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@ -166,7 +166,7 @@ int crypto_expand_key_material(const char *key_in, size_t in_len,
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char *key_out, size_t key_out_len);
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/* random numbers */
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int crypto_seed_rng(void);
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int crypto_seed_rng(int startup);
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int crypto_rand(char *to, size_t n);
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int crypto_rand_int(unsigned int max);
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uint64_t crypto_rand_uint64(uint64_t max);
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@ -900,7 +900,7 @@ run_scheduled_events(time_t now)
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if (time_to_add_entropy < now) {
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if (time_to_add_entropy) {
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/* We already seeded once, so don't die on failure. */
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crypto_seed_rng();
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crypto_seed_rng(0);
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}
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/** How often do we add more entropy to OpenSSL's RNG pool? */
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#define ENTROPY_INTERVAL (60*60)
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@ -1810,7 +1810,7 @@ tor_init(int argc, char *argv[])
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#endif
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crypto_global_init(get_options()->HardwareAccel);
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if (crypto_seed_rng()) {
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if (crypto_seed_rng(1)) {
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log_err(LD_BUG, "Unable to seed random number generator. Exiting.");
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return -1;
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}
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