Date: Thu, 2 Sep 2004 19:20:17 +0300 From: Peter Pentchev <roam@ringlet.net> To: freebsd-hackers@FreeBSD.org Cc: Dag-Erling Smorgrav <des@FreeBSD.org> Subject: Re: [CFR] OpenSSL ENGINE fix Message-ID: <20040902162017.GI1469@straylight.m.ringlet.net> In-Reply-To: <20040902160300.GH1469@straylight.m.ringlet.net> References: <20040902160300.GH1469@straylight.m.ringlet.net>
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On Thu, Sep 02, 2004 at 07:03:00PM +0300, Peter Pentchev wrote:
> Hi,
>
> The stunnel port had been badly broken on -CURRENT for some time, and
> today I seem to have tracked it down. There is a problem in
> OpenSSL's ENGINE code, which seems to depend on realloc()'s initializing
> unused memory with zeroes. Since this is certainly not true with
> malloc's 'J' option, the ENGINE code never actually runs out of RAND
> routines to look for, and dumps core on attempting to dereference a
> structure at 0xd0d0d0d0.
>
> The following simple patch seems to fix this particular problem, but I
> think there are others lurking close beneath the surface. When I built
> stunnel with this patch, it did not immediately segfault on
> initialization, but it did later, when it attempted to get a couple of
> random bytes in order to actually establish an SSL connection. A quick
> examination shows that the ENGINE code had "successfully" loaded and
> initialized all built-in engines and then tried to use the last one
> loaded - in this case, the 4758cca one - which promptly invoked a
> function pointed to by the static randomNumberGenerate variable, which,
> as you may have guessed by this point, held a NULL value. Apparently,
> something else is rotten in ENGINE initialization land, and (at least)
> the 4758cca driver cannot properly detect that it has not properly
> detected its hardware :(
Oh, and of course, here's a program that demonstrates the null pointer
problem after the eng_table.c patch is applied:
#include <openssl/lhash.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#include <openssl/crypto.h> /* for CRYPTO_* and SSLeay_version */
#include <openssl/rand.h>
#if SSLEAY_VERSION_NUMBER >= 0x00907000L
#include <openssl/engine.h>
#else
#error weird openssl version
#endif
int main(void)
{
unsigned char buf[256];
int ret;
ENGINE_load_builtin_engines();
ENGINE_register_all_complete();
if (RAND_status()) {
printf("RAND_status said ok\n");
} else {
printf("RAND_status kinda sorta failed\n");
}
ret = RAND_pseudo_bytes(buf, sizeof(buf) / 2);
printf("RAND_pseudo_bytes() returned %d\n", ret);
return (0);
}
G'luck,
Peter
--
Peter Pentchev roam@ringlet.net roam@cnsys.bg roam@FreeBSD.org
PGP key: http://people.FreeBSD.org/~roam/roam.key.asc
Key fingerprint FDBA FD79 C26F 3C51 C95E DF9E ED18 B68D 1619 4553
If I had finished this sentence,
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