Index: crypto/openssl/crypto/bn/bn.h =================================================================== --- crypto/openssl/crypto/bn/bn.h (revision 264251) +++ crypto/openssl/crypto/bn/bn.h (working copy) @@ -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 Index: crypto/openssl/crypto/bn/bn_lib.c =================================================================== --- crypto/openssl/crypto/bn/bn_lib.c (revision 264251) +++ crypto/openssl/crypto/bn/bn_lib.c (working copy) @@ -824,3 +824,55 @@ int bn_cmp_part_words(const BN_ULONG *a, const BN_ } 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 +} Index: crypto/openssl/crypto/ec/ec2_mult.c =================================================================== --- crypto/openssl/crypto/ec/ec2_mult.c (revision 264251) +++ crypto/openssl/crypto/ec/ec2_mult.c (working copy) @@ -208,11 +208,15 @@ static int gf2m_Mxy(const EC_GROUP *group, const B 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 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 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; Index: crypto/openssl/ssl/d1_both.c =================================================================== --- crypto/openssl/ssl/d1_both.c (revision 264251) +++ crypto/openssl/ssl/d1_both.c (working copy) @@ -1458,26 +1458,36 @@ dtls1_process_heartbeat(SSL *s) unsigned int payload; unsigned int padding = 16; /* Use minimum padding */ + 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 (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); - 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 */ @@ -1488,11 +1498,11 @@ 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); Index: crypto/openssl/ssl/t1_lib.c =================================================================== --- crypto/openssl/ssl/t1_lib.c (revision 264251) +++ crypto/openssl/ssl/t1_lib.c (working copy) @@ -2486,16 +2486,20 @@ tls1_process_heartbeat(SSL *s) unsigned int payload; unsigned int padding = 16; /* Use minimum padding */ + 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 (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); - if (hbtype == TLS1_HB_REQUEST) { unsigned char *buffer, *bp;