Fix NFS deadlock vulnerability. [SA-14:05]

Fix "Heartbleed" vulnerability and ECDSA Cache Side-channel
Attack in OpenSSL. [SA-14:06]
This commit is contained in:
Xin LI 2014-04-08 18:27:32 +00:00
parent 1fa3ca3ca7
commit 25bfde79d6
6 changed files with 126 additions and 29 deletions

View File

@ -538,6 +538,8 @@ 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,
@ -774,11 +776,20 @@ int RAND_pseudo_bytes(unsigned char *buf,int num);
#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

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@ -824,3 +824,55 @@ int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
}
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
}

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@ -208,11 +208,15 @@ static int gf2m_Mxy(const EC_GROUP *group, const BIGNUM *x, const BIGNUM *y, BIG
return ret;
}
/* Computes scalar*point and stores the result in r.
* point can not equal r.
* Uses algorithm 2P of
* Uses a modified algorithm 2P of
* Lopez, J. and Dahab, R. "Fast multiplication on elliptic curves over
* GF(2^m) without precomputation" (CHES '99, LNCS 1717).
*
* 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)
@ -246,6 +250,11 @@ static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r,
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 */
@ -270,16 +279,12 @@ static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r,
word = scalar->d[i];
while (mask)
{
if (word & 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(word & mask, x1, x2, group->field.top);
BN_consttime_swap(word & 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(word & mask, x1, x2, group->field.top);
BN_consttime_swap(word & mask, z1, z2, group->field.top);
mask >>= 1;
}
mask = BN_TBIT;

View File

@ -1459,26 +1459,36 @@ dtls1_process_heartbeat(SSL *s)
unsigned int payload;
unsigned int padding = 16; /* Use minimum padding */
/* Read type and payload length first */
hbtype = *p++;
n2s(p, payload);
pl = p;
if (s->msg_callback)
s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
&s->s3->rrec.data[0], s->s3->rrec.length,
s, s->msg_callback_arg);
/* Read type and payload length first */
if (1 + 2 + 16 > s->s3->rrec.length)
return 0; /* silently discard */
hbtype = *p++;
n2s(p, payload);
if (1 + 2 + payload + 16 > s->s3->rrec.length)
return 0; /* silently discard per RFC 6520 sec. 4 */
pl = p;
if (hbtype == TLS1_HB_REQUEST)
{
unsigned char *buffer, *bp;
unsigned int write_length = 1 /* heartbeat type */ +
2 /* heartbeat length */ +
payload + padding;
int r;
if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
return 0;
/* Allocate memory for the response, size is 1 byte
* message type, plus 2 bytes payload length, plus
* payload, plus padding
*/
buffer = OPENSSL_malloc(1 + 2 + payload + padding);
buffer = OPENSSL_malloc(write_length);
bp = buffer;
/* Enter response type, length and copy payload */
@ -1489,11 +1499,11 @@ dtls1_process_heartbeat(SSL *s)
/* Random padding */
RAND_pseudo_bytes(bp, padding);
r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, 3 + payload + padding);
r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
if (r >= 0 && s->msg_callback)
s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
buffer, 3 + payload + padding,
buffer, write_length,
s, s->msg_callback_arg);
OPENSSL_free(buffer);

View File

@ -2558,16 +2558,20 @@ tls1_process_heartbeat(SSL *s)
unsigned int payload;
unsigned int padding = 16; /* Use minimum padding */
/* Read type and payload length first */
hbtype = *p++;
n2s(p, payload);
pl = p;
if (s->msg_callback)
s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
&s->s3->rrec.data[0], s->s3->rrec.length,
s, s->msg_callback_arg);
/* Read type and payload length first */
if (1 + 2 + 16 > s->s3->rrec.length)
return 0; /* silently discard */
hbtype = *p++;
n2s(p, payload);
if (1 + 2 + payload + 16 > s->s3->rrec.length)
return 0; /* silently discard per RFC 6520 sec. 4 */
pl = p;
if (hbtype == TLS1_HB_REQUEST)
{
unsigned char *buffer, *bp;

View File

@ -1457,10 +1457,23 @@ nfsrvd_rename(struct nfsrv_descript *nd, int isdgram,
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, int isdgram,
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, int isdgram,
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, int isdgram,
}
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, int isdgram,
/*
* 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,