On Wed, May 13, 2020 at 04:01:03PM +0300, Jouni Malinen wrote:
> On Wed, May 13, 2020 at 11:46:03AM +0100, Daniel Golle wrote:
> > Odd, but could be endian or sizeof(int) related differences. I assume
> > you are testing on x86_64 glibc while I'm testing this on MIPS24kc
> > (big endian!) with musl libc running on QCA SoCs.
>
> Unfortunately, I don't have any convenient means for testing this
> combination on a big endian system. That said, the identified commit
> does not really have any area that would seem to be depending on
> endianness or word size of the CPU..
>
> > I've tried plain wpa_supplicant as well as with OpenWrt's patches, all
> > build against WolfSSL 4.3.0-stable.
> >
> > using git revision 2b84ca4d :
> >
> > root@OpenWrt:~# wpa_supplicant -ddd -P
> > /var/run/wpa_supplicant-wlan1-mesh.pid -D nl80211 -i wlan1-mesh -c
> > /var/run/wpa_supplicant-wlan1-mesh.conf
> > Successfully initialized wpa_supplicant
> > Using interface wlan1-mesh with hwaddr 64:70:02:xx:xx:xx and ssid ""
> > wlan1-mesh: interface state UNINITIALIZED->ENABLED
> > wlan1-mesh: AP-ENABLED
> > wlan1-mesh: joining mesh LiMe
> ...
>
> This wpa_supplicant build lacks all debugging detail.. Could you please
> enable full debugging, i.e., remove whatever OpenWrt patches and/or
> build configuration does to disable debugging? Without the details,
> there is not really much that can be done do figure out what exactly is
> failing since none of the SAE details are shown here.
I'm about to send you full logs (rather large) off-list.
>
> > The build environment is currently on an otherwise unused system wired
> > up to the two QCA devices for testing. We could arrange remote access
> > remote access via SSH or you can tell me to build/test whatever you'd
> > like me to and I'll report back.
> > If you'd like to reproduce this locally or even include in your CI,
> > I guess that building Linux and wpa_supplicant for MIPS Malta (BE) and
> > running that in qemu-system-mips will show similar results as my
> > testing on real hardware.
>
> I guess it would be nice to get a big endian setup added for automated
> testing eventually, but setting that up with qemu sounds like something
> that is going to take significant amount of effort..
>
> Could you please check that the following patch fixes the issue? In
> practice, this is reverting any functional difference of commit
> 6c9543fcb for SAE. This should not really fix anything based on code
> review, but I want to make sure that it is indeed this particular commit
> that explains the real issue before spending significant effort in
> figuring out how the move from wpa_supplicant internal random number
> generation to WolfSSL mp_rand_prime() could cause this type of an issue
> on some platforms (but not on x86-64).
That didn't help, unfortunately.
>
>
>
> diff --git a/src/common/dragonfly.c b/src/common/dragonfly.c
> index 547be66f1561..6bce5ee4e4fb 100644
> --- a/src/common/dragonfly.c
> +++ b/src/common/dragonfly.c
> @@ -8,10 +8,13 @@
> */
>
> #include "utils/includes.h"
> +#include <wolfssl/options.h>
> +#include <wolfssl/wolfcrypt/tfm.h>
>
> #include "utils/common.h"
> #include "utils/const_time.h"
> #include "crypto/crypto.h"
> +#include "crypto/random.h"
> #include "dragonfly.h"
>
>
> @@ -54,33 +57,41 @@ int dragonfly_get_random_qr_qnr(const struct
> crypto_bignum *prime,
> struct crypto_bignum **qr,
> struct crypto_bignum **qnr)
> {
> + size_t prime_bits = mp_count_bits((mp_int *) prime);
> + size_t prime_len = (prime_bits + 7) / 8;
> + u8 prime_bin[DRAGONFLY_MAX_ECC_PRIME_LEN];
> +
> + if (crypto_bignum_to_bin(prime, prime_bin, sizeof(prime_bin),
> + prime_len) < 0)
> + return -1;
> +
> *qr = *qnr = NULL;
>
> while (!(*qr) || !(*qnr)) {
> - struct crypto_bignum *tmp;
> + u8 tmp[DRAGONFLY_MAX_ECC_PRIME_LEN];
> + struct crypto_bignum *q;
> int res;
>
> - tmp = crypto_bignum_init();
> - if (!tmp || crypto_bignum_rand(tmp, prime) < 0) {
> - crypto_bignum_deinit(tmp, 0);
> + if (random_get_bytes(tmp, prime_len) < 0)
> break;
> - }
> + if (prime_bits % 8)
> + buf_shift_right(tmp, prime_len, 8 - prime_bits % 8);
> + if (os_memcmp(tmp, prime_bin, prime_len) >= 0)
> + continue;
> + q = crypto_bignum_init_set(tmp, prime_len);
> + if (!q)
> + break;
> + res = crypto_bignum_legendre(q, prime);
>
> - res = crypto_bignum_legendre(tmp, prime);
> if (res == 1 && !(*qr))
> - *qr = tmp;
> + *qr = q;
> else if (res == -1 && !(*qnr))
> - *qnr = tmp;
> + *qnr = q;
> else
> - crypto_bignum_deinit(tmp, 0);
> + crypto_bignum_deinit(q, 0);
> }
>
> - if (*qr && *qnr)
> - return 0;
> - crypto_bignum_deinit(*qr, 0);
> - crypto_bignum_deinit(*qnr, 0);
> - *qr = *qnr = NULL;
> - return -1;
> + return (*qr && *qnr) ? 0 : -1;
> }
>
>
>
> --
> Jouni Malinen PGP id EFC895FA
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