Date: Tue, 8 Apr 2014 23:16:20 +0000 (UTC) From: Xin LI <delphij@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org Subject: svn commit: r264285 - in stable: 8/crypto/openssl/crypto/bn 8/crypto/openssl/crypto/ec 8/sys/fs/nfsserver 9/crypto/openssl/crypto/bn 9/crypto/openssl/crypto/ec 9/sys/fs/nfsserver Message-ID: <201404082316.s38NGKt1068823@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
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/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 Changes in other areas also in this revision: 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 Modified: stable/8/crypto/openssl/crypto/bn/bn.h ============================================================================== --- stable/8/crypto/openssl/crypto/bn/bn.h Tue Apr 8 23:16:05 2014 (r264284) +++ stable/8/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/8/crypto/openssl/crypto/bn/bn_lib.c ============================================================================== --- stable/8/crypto/openssl/crypto/bn/bn_lib.c Tue Apr 8 23:16:05 2014 (r264284) +++ stable/8/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/8/crypto/openssl/crypto/ec/ec2_mult.c ============================================================================== --- stable/8/crypto/openssl/crypto/ec/ec2_mult.c Tue Apr 8 23:16:05 2014 (r264284) +++ stable/8/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/8/sys/fs/nfsserver/nfs_nfsdserv.c ============================================================================== --- stable/8/sys/fs/nfsserver/nfs_nfsdserv.c Tue Apr 8 23:16:05 2014 (r264284) +++ stable/8/sys/fs/nfsserver/nfs_nfsdserv.c Tue Apr 8 23:16:19 2014 (r264285) @@ -1446,10 +1446,23 @@ 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); @@ -1470,10 +1483,12 @@ 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); @@ -1488,7 +1503,7 @@ nfsrvd_rename(struct nfsrv_descript *nd, if (error) { if (tdp) vrele(tdp); - vput(dp); + vrele(dp); nfsvno_relpathbuf(&fromnd); nfsvno_relpathbuf(&tond); goto out; @@ -1503,7 +1518,7 @@ nfsrvd_rename(struct nfsrv_descript *nd, } if (tdp) vrele(tdp); - vput(dp); + vrele(dp); nfsvno_relpathbuf(&fromnd); nfsvno_relpathbuf(&tond); goto out; @@ -1512,7 +1527,7 @@ 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,
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201404082316.s38NGKt1068823>