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Simplify sigalgs code.
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Remove unnecessary lookup operations: use the indices and data in the
lookup table directly.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from #2324)
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@snhenson
snhenson committed Jan 31, 2017
1 parent 17ae384 commit 44b6318
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Showing 2 changed files with 19 additions and 65 deletions.
1 change: 0 additions & 1 deletion ssl/ssl_locl.h
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Expand Up @@ -2241,7 +2241,6 @@ __owur int tls_use_ticket(SSL *s);

__owur int tls12_get_sigandhash(SSL *s, WPACKET *pkt, const EVP_PKEY *pk,
const EVP_MD *md, int *ispss);
__owur const EVP_MD *tls12_get_hash(int hash_nid);
void ssl_set_sig_mask(uint32_t *pmask_a, SSL *s, int op);

__owur int tls1_set_sigalgs_list(CERT *c, const char *str, int client);
Expand Down
83 changes: 19 additions & 64 deletions ssl/t1_lib.c
View file
Expand Up @@ -785,13 +785,6 @@ static const SIGALG_LOOKUP *tls1_lookup_sigalg(uint16_t sigalg)
return NULL;
}

static int tls_sigalg_get_hash(uint16_t sigalg)
{
const SIGALG_LOOKUP *r = tls1_lookup_sigalg(sigalg);

return r != NULL ? r->hash : 0;
}

static int tls_sigalg_get_sig(uint16_t sigalg)
{
const SIGALG_LOOKUP *r = tls1_lookup_sigalg(sigalg);
Expand Down Expand Up @@ -870,15 +863,18 @@ int tls12_check_peer_sigalg(SSL *s, uint16_t sig, EVP_PKEY *pkey)
#ifndef OPENSSL_NO_EC
if (pkeyid == EVP_PKEY_EC) {
EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);

if (SSL_IS_TLS13(s)) {
/* For TLS 1.3 check curve matches signature algorithm */
int curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));

if (curve != lu->curve) {
SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG, SSL_R_WRONG_CURVE);
return 0;
}
} else {
unsigned char curve_id[2], comp_id;

/* Check compression and curve matches extensions */
if (!tls1_set_ec_id(curve_id, &comp_id, ec))
return 0;
Expand All @@ -891,13 +887,13 @@ int tls12_check_peer_sigalg(SSL *s, uint16_t sig, EVP_PKEY *pkey)
if (curve_id[0])
return 0;
if (curve_id[1] == TLSEXT_curve_P_256) {
if (tls_sigalg_get_hash(sig) != NID_sha256) {
if (lu->hash != NID_sha256) {
SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG,
SSL_R_ILLEGAL_SUITEB_DIGEST);
return 0;
}
} else if (curve_id[1] == TLSEXT_curve_P_384) {
if (tls_sigalg_get_hash(sig) != NID_sha384) {
if (lu->hash != NID_sha384) {
SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG,
SSL_R_ILLEGAL_SUITEB_DIGEST);
return 0;
Expand All @@ -924,7 +920,7 @@ int tls12_check_peer_sigalg(SSL *s, uint16_t sig, EVP_PKEY *pkey)
SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG, SSL_R_WRONG_SIGNATURE_TYPE);
return 0;
}
md = tls12_get_hash(lu->hash);
md = ssl_md(lu->hash_idx);
if (md == NULL) {
SSLerr(SSL_F_TLS12_CHECK_PEER_SIGALG, SSL_R_UNKNOWN_DIGEST);
return 0;
Expand Down Expand Up @@ -1360,49 +1356,6 @@ int tls12_get_sigandhash(SSL *s, WPACKET *pkt, const EVP_PKEY *pk,
return 0;
}

typedef struct {
int nid;
int secbits;
int md_idx;
} tls12_hash_info;

static const tls12_hash_info tls12_md_info[] = {
{NID_md5, 64, SSL_MD_MD5_IDX},
{NID_sha1, 80, SSL_MD_SHA1_IDX},
{NID_sha224, 112, SSL_MD_SHA224_IDX},
{NID_sha256, 128, SSL_MD_SHA256_IDX},
{NID_sha384, 192, SSL_MD_SHA384_IDX},
{NID_sha512, 256, SSL_MD_SHA512_IDX},
{NID_id_GostR3411_94, 128, SSL_MD_GOST94_IDX},
{NID_id_GostR3411_2012_256, 128, SSL_MD_GOST12_256_IDX},
{NID_id_GostR3411_2012_512, 256, SSL_MD_GOST12_512_IDX},
};

static const tls12_hash_info *tls12_get_hash_info(int hash_nid)
{
unsigned int i;
if (hash_nid == NID_undef)
return NULL;

for (i = 0; i < OSSL_NELEM(tls12_md_info); i++) {
if (tls12_md_info[i].nid == hash_nid)
return tls12_md_info + i;
}

return NULL;
}

const EVP_MD *tls12_get_hash(int hash_nid)
{
const tls12_hash_info *inf;
if (hash_nid == NID_md5 && FIPS_mode())
return NULL;
inf = tls12_get_hash_info(hash_nid);
if (!inf)
return NULL;
return ssl_md(inf->md_idx);
}

static int tls12_get_pkey_idx(int sig_nid)
{
switch (sig_nid) {
Expand Down Expand Up @@ -1439,22 +1392,24 @@ static int tls12_get_pkey_idx(int sig_nid)
}

/* Check to see if a signature algorithm is allowed */
static int tls12_sigalg_allowed(SSL *s, int op, unsigned int ptmp)
static int tls12_sigalg_allowed(SSL *s, int op, uint16_t ptmp)
{
/* See if we have an entry in the hash table and it is enabled */
const tls12_hash_info *hinf
= tls12_get_hash_info(tls_sigalg_get_hash(ptmp));
const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(ptmp);
unsigned char sigalgstr[2];
int secbits;

if (hinf == NULL || ssl_md(hinf->md_idx) == NULL)
/* See if sigalgs is recognised and if hash is enabled */
if (lu == NULL || ssl_md(lu->hash_idx) == NULL)
return 0;
/* See if public key algorithm allowed */
if (tls12_get_pkey_idx(tls_sigalg_get_sig(ptmp)) == -1)
if (tls12_get_pkey_idx(lu->sig) == -1)
return 0;
/* Security bits: half digest bits */
secbits = EVP_MD_size(ssl_md(lu->hash_idx)) * 4;
/* Finally see if security callback allows it */
sigalgstr[0] = (ptmp >> 8) & 0xff;
sigalgstr[1] = ptmp & 0xff;
return ssl_security(s, op, hinf->secbits, hinf->nid, (void *)sigalgstr);
return ssl_security(s, op, secbits, lu->hash, (void *)sigalgstr);
}

/*
Expand Down Expand Up @@ -1650,15 +1605,14 @@ int tls1_process_sigalgs(SSL *s)
continue;
idx = tls12_get_pkey_idx(sigptr->sig);
if (idx > 0 && pmd[idx] == NULL) {
md = tls12_get_hash(sigptr->hash);
md = ssl_md(sigptr->hash_idx);
pmd[idx] = md;
pvalid[idx] = CERT_PKEY_EXPLICIT_SIGN;
if (idx == SSL_PKEY_RSA_SIGN) {
pvalid[SSL_PKEY_RSA_ENC] = CERT_PKEY_EXPLICIT_SIGN;
pmd[SSL_PKEY_RSA_ENC] = md;
}
}

}
/*
* In strict mode or TLS1.3 leave unset digests as NULL to indicate we can't
Expand Down Expand Up @@ -2037,8 +1991,9 @@ int tls1_check_chain(SSL *s, X509 *x, EVP_PKEY *pk, STACK_OF(X509) *chain,
size_t j;
const uint16_t *p = c->conf_sigalgs;
for (j = 0; j < c->conf_sigalgslen; j++, p++) {
if (tls_sigalg_get_hash(*p) == NID_sha1
&& tls_sigalg_get_sig(*p) == rsign)
const SIGALG_LOOKUP *lu = tls1_lookup_sigalg(*p);

if (lu != NULL && lu->hash == NID_sha1 && lu->sig == rsign)
break;
}
if (j == c->conf_sigalgslen) {
Expand Down

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