Author: delphij
Date: Tue Apr 8 23:16:19 2014
New Revision: 264285
URL: http://svnweb.freebsd.org/changeset/base/264285
Log:
Fix NFS deadlock vulnerability. [SA-14:05]
Fix ECDSA Cache Side-channel Attack in OpenSSL. [SA-14:06]
Modified:
stable/9/crypto/openssl/crypto/bn/bn.h
stable/9/crypto/openssl/crypto/bn/bn_lib.c
stable/9/crypto/openssl/crypto/ec/ec2_mult.c
stable/9/sys/fs/nfsserver/nfs_nfsdserv.c
Changes in other areas also in this revision:
Modified:
stable/8/crypto/openssl/crypto/bn/bn.h
stable/8/crypto/openssl/crypto/bn/bn_lib.c
stable/8/crypto/openssl/crypto/ec/ec2_mult.c
stable/8/sys/fs/nfsserver/nfs_nfsdserv.c
Modified: stable/9/crypto/openssl/crypto/bn/bn.h
==============================================================================
--- stable/9/crypto/openssl/crypto/bn/bn.h Tue Apr 8 23:16:05 2014
(r264284)
+++ stable/9/crypto/openssl/crypto/bn/bn.h Tue Apr 8 23:16:19 2014
(r264285)
@@ -511,6 +511,8 @@ BIGNUM *BN_mod_inverse(BIGNUM *ret,
BIGNUM *BN_mod_sqrt(BIGNUM *ret,
const BIGNUM *a, const BIGNUM *n,BN_CTX *ctx);
+void BN_consttime_swap(BN_ULONG swap, BIGNUM *a, BIGNUM *b, int nwords);
+
/* Deprecated versions */
#ifndef OPENSSL_NO_DEPRECATED
BIGNUM *BN_generate_prime(BIGNUM *ret,int bits,int safe,
@@ -740,11 +742,20 @@ int RAND_pseudo_bytes(unsigned char *buf
#define bn_fix_top(a) bn_check_top(a)
+#define bn_check_size(bn, bits) bn_wcheck_size(bn,
((bits+BN_BITS2-1))/BN_BITS2)
+#define bn_wcheck_size(bn, words) \
+ do { \
+ const BIGNUM *_bnum2 = (bn); \
+ assert(words <= (_bnum2)->dmax && words >= (_bnum2)->top); \
+ } while(0)
+
#else /* !BN_DEBUG */
#define bn_pollute(a)
#define bn_check_top(a)
#define bn_fix_top(a) bn_correct_top(a)
+#define bn_check_size(bn, bits)
+#define bn_wcheck_size(bn, words)
#endif
Modified: stable/9/crypto/openssl/crypto/bn/bn_lib.c
==============================================================================
--- stable/9/crypto/openssl/crypto/bn/bn_lib.c Tue Apr 8 23:16:05 2014
(r264284)
+++ stable/9/crypto/openssl/crypto/bn/bn_lib.c Tue Apr 8 23:16:19 2014
(r264285)
@@ -824,3 +824,55 @@ int bn_cmp_part_words(const BN_ULONG *a,
}
return bn_cmp_words(a,b,cl);
}
+
+/*
+ * Constant-time conditional swap of a and b.
+ * a and b are swapped if condition is not 0. The code assumes that at most
one bit of condition is set.
+ * nwords is the number of words to swap. The code assumes that at least
nwords are allocated in both a and b,
+ * and that no more than nwords are used by either a or b.
+ * a and b cannot be the same number
+ */
+void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
+ {
+ BN_ULONG t;
+ int i;
+
+ bn_wcheck_size(a, nwords);
+ bn_wcheck_size(b, nwords);
+
+ assert(a != b);
+ assert((condition & (condition - 1)) == 0);
+ assert(sizeof(BN_ULONG) >= sizeof(int));
+
+ condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
+
+ t = (a->top^b->top) & condition;
+ a->top ^= t;
+ b->top ^= t;
+
+#define BN_CONSTTIME_SWAP(ind) \
+ do { \
+ t = (a->d[ind] ^ b->d[ind]) & condition; \
+ a->d[ind] ^= t; \
+ b->d[ind] ^= t; \
+ } while (0)
+
+
+ switch (nwords) {
+ default:
+ for (i = 10; i < nwords; i++)
+ BN_CONSTTIME_SWAP(i);
+ /* Fallthrough */
+ case 10: BN_CONSTTIME_SWAP(9); /* Fallthrough */
+ case 9: BN_CONSTTIME_SWAP(8); /* Fallthrough */
+ case 8: BN_CONSTTIME_SWAP(7); /* Fallthrough */
+ case 7: BN_CONSTTIME_SWAP(6); /* Fallthrough */
+ case 6: BN_CONSTTIME_SWAP(5); /* Fallthrough */
+ case 5: BN_CONSTTIME_SWAP(4); /* Fallthrough */
+ case 4: BN_CONSTTIME_SWAP(3); /* Fallthrough */
+ case 3: BN_CONSTTIME_SWAP(2); /* Fallthrough */
+ case 2: BN_CONSTTIME_SWAP(1); /* Fallthrough */
+ case 1: BN_CONSTTIME_SWAP(0);
+ }
+#undef BN_CONSTTIME_SWAP
+}
Modified: stable/9/crypto/openssl/crypto/ec/ec2_mult.c
==============================================================================
--- stable/9/crypto/openssl/crypto/ec/ec2_mult.c Tue Apr 8 23:16:05
2014 (r264284)
+++ stable/9/crypto/openssl/crypto/ec/ec2_mult.c Tue Apr 8 23:16:19
2014 (r264285)
@@ -208,9 +208,12 @@ static int gf2m_Mxy(const EC_GROUP *grou
/* Computes scalar*point and stores the result in r.
* point can not equal r.
- * Uses algorithm 2P of
+ * Uses a modified algorithm 2P of
* Lopex, J. and Dahab, R. "Fast multiplication on elliptic curves over
* GF(2^m) without precomputation".
+ *
+ * To protect against side-channel attack the function uses constant time
+ * swap avoiding conditional branches.
*/
static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT
*r, const BIGNUM *scalar,
const EC_POINT *point, BN_CTX *ctx)
@@ -244,6 +247,11 @@ static int ec_GF2m_montgomery_point_mult
x2 = &r->X;
z2 = &r->Y;
+ bn_wexpand(x1, group->field.top);
+ bn_wexpand(z1, group->field.top);
+ bn_wexpand(x2, group->field.top);
+ bn_wexpand(z2, group->field.top);
+
if (!BN_GF2m_mod_arr(x1, &point->X, group->poly)) goto err; /* x1 = x */
if (!BN_one(z1)) goto err; /* z1 = 1 */
if (!group->meth->field_sqr(group, z2, x1, ctx)) goto err; /* z2 = x1^2
= x^2 */
@@ -266,16 +274,12 @@ static int ec_GF2m_montgomery_point_mult
{
for (; j >= 0; j--)
{
- if (scalar->d[i] & mask)
- {
- if (!gf2m_Madd(group, &point->X, x1, z1, x2,
z2, ctx)) goto err;
- if (!gf2m_Mdouble(group, x2, z2, ctx)) goto err;
- }
- else
- {
- if (!gf2m_Madd(group, &point->X, x2, z2, x1,
z1, ctx)) goto err;
- if (!gf2m_Mdouble(group, x1, z1, ctx)) goto err;
- }
+ BN_consttime_swap(scalar->d[i] & mask, x1, x2,
group->field.top);
+ BN_consttime_swap(scalar->d[i] & mask, z1, z2,
group->field.top);
+ if (!gf2m_Madd(group, &point->X, x2, z2, x1, z1, ctx))
goto err;
+ if (!gf2m_Mdouble(group, x1, z1, ctx)) goto err;
+ BN_consttime_swap(scalar->d[i] & mask, x1, x2,
group->field.top);
+ BN_consttime_swap(scalar->d[i] & mask, z1, z2,
group->field.top);
mask >>= 1;
}
j = BN_BITS2 - 1;
Modified: stable/9/sys/fs/nfsserver/nfs_nfsdserv.c
==============================================================================
--- stable/9/sys/fs/nfsserver/nfs_nfsdserv.c Tue Apr 8 23:16:05 2014
(r264284)
+++ stable/9/sys/fs/nfsserver/nfs_nfsdserv.c Tue Apr 8 23:16:19 2014
(r264285)
@@ -1457,10 +1457,23 @@ nfsrvd_rename(struct nfsrv_descript *nd,
nfsvno_relpathbuf(&fromnd);
goto out;
}
+ /*
+ * Unlock dp in this code section, so it is unlocked before
+ * tdp gets locked. This avoids a potential LOR if tdp is the
+ * parent directory of dp.
+ */
if (nd->nd_flag & ND_NFSV4) {
tdp = todp;
tnes = *toexp;
- tdirfor_ret = nfsvno_getattr(tdp, &tdirfor, nd->nd_cred, p, 0);
+ if (dp != tdp) {
+ NFSVOPUNLOCK(dp, 0);
+ tdirfor_ret = nfsvno_getattr(tdp, &tdirfor, nd->nd_cred,
+ p, 0); /* Might lock tdp. */
+ } else {
+ tdirfor_ret = nfsvno_getattr(tdp, &tdirfor, nd->nd_cred,
+ p, 1);
+ NFSVOPUNLOCK(dp, 0);
+ }
} else {
tfh.nfsrvfh_len = 0;
error = nfsrv_mtofh(nd, &tfh);
@@ -1481,10 +1494,12 @@ nfsrvd_rename(struct nfsrv_descript *nd,
tnes = *exp;
tdirfor_ret = nfsvno_getattr(tdp, &tdirfor, nd->nd_cred,
p, 1);
+ NFSVOPUNLOCK(dp, 0);
} else {
+ NFSVOPUNLOCK(dp, 0);
nd->nd_cred->cr_uid = nd->nd_saveduid;
nfsd_fhtovp(nd, &tfh, LK_EXCLUSIVE, &tdp, &tnes, NULL,
- 0, p);
+ 0, p); /* Locks tdp. */
if (tdp) {
tdirfor_ret = nfsvno_getattr(tdp, &tdirfor,
nd->nd_cred, p, 1);
@@ -1499,7 +1514,7 @@ nfsrvd_rename(struct nfsrv_descript *nd,
if (error) {
if (tdp)
vrele(tdp);
- vput(dp);
+ vrele(dp);
nfsvno_relpathbuf(&fromnd);
nfsvno_relpathbuf(&tond);
goto out;
@@ -1514,7 +1529,7 @@ nfsrvd_rename(struct nfsrv_descript *nd,
}
if (tdp)
vrele(tdp);
- vput(dp);
+ vrele(dp);
nfsvno_relpathbuf(&fromnd);
nfsvno_relpathbuf(&tond);
goto out;
@@ -1523,7 +1538,7 @@ nfsrvd_rename(struct nfsrv_descript *nd,
/*
* Done parsing, now down to business.
*/
- nd->nd_repstat = nfsvno_namei(nd, &fromnd, dp, 1, exp, p, &fdirp);
+ nd->nd_repstat = nfsvno_namei(nd, &fromnd, dp, 0, exp, p, &fdirp);
if (nd->nd_repstat) {
if (nd->nd_flag & ND_NFSV3) {
nfsrv_wcc(nd, fdirfor_ret, &fdirfor, fdiraft_ret,
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