diff options
author | Matt Caswell <matt@openssl.org> | 2018-12-04 08:37:04 +0000 |
---|---|---|
committer | Matt Caswell <matt@openssl.org> | 2018-12-05 10:55:04 +0000 |
commit | 0fb2815b873304d145ed00283454fc9f3bd35e6b (patch) | |
tree | 25e40e4f76270869ce4053ad2af0beb5ab7304bd /ssl/tls13_enc.c | |
parent | ed371b8cbac0d0349667558c061c1ae380cf75eb (diff) |
Fix some SSL_export_keying_material() issues
Fix some issues in tls13_hkdf_expand() which impact the above function
for TLSv1.3. In particular test that we can use the maximum label length
in TLSv1.3.
Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7755)
Diffstat (limited to 'ssl/tls13_enc.c')
-rw-r--r-- | ssl/tls13_enc.c | 73 |
1 files changed, 49 insertions, 24 deletions
diff --git a/ssl/tls13_enc.c b/ssl/tls13_enc.c index f7ab0fa470..c3021d18aa 100644 --- a/ssl/tls13_enc.c +++ b/ssl/tls13_enc.c @@ -13,7 +13,7 @@ #include <openssl/evp.h> #include <openssl/kdf.h> -#define TLS13_MAX_LABEL_LEN 246 +#define TLS13_MAX_LABEL_LEN 249 /* Always filled with zeros */ static const unsigned char default_zeros[EVP_MAX_MD_SIZE]; @@ -22,30 +22,47 @@ static const unsigned char default_zeros[EVP_MAX_MD_SIZE]; * Given a |secret|; a |label| of length |labellen|; and |data| of length * |datalen| (e.g. typically a hash of the handshake messages), derive a new * secret |outlen| bytes long and store it in the location pointed to be |out|. - * The |data| value may be zero length. Returns 1 on success 0 on failure. + * The |data| value may be zero length. Any errors will be treated as fatal if + * |fatal| is set. Returns 1 on success 0 on failure. */ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret, const unsigned char *label, size_t labellen, const unsigned char *data, size_t datalen, - unsigned char *out, size_t outlen) + unsigned char *out, size_t outlen, int fatal) { - const unsigned char label_prefix[] = "tls13 "; + static const unsigned char label_prefix[] = "tls13 "; EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL); int ret; size_t hkdflabellen; size_t hashlen; /* - * 2 bytes for length of whole HkdfLabel + 1 byte for length of combined - * prefix and label + bytes for the label itself + bytes for the hash + * 2 bytes for length of derived secret + 1 byte for length of combined + * prefix and label + bytes for the label itself + 1 byte length of hash + * + bytes for the hash itself */ unsigned char hkdflabel[sizeof(uint16_t) + sizeof(uint8_t) + + sizeof(label_prefix) + TLS13_MAX_LABEL_LEN - + EVP_MAX_MD_SIZE]; + + 1 + EVP_MAX_MD_SIZE]; WPACKET pkt; if (pctx == NULL) return 0; + if (labellen > TLS13_MAX_LABEL_LEN) { + if (fatal) { + SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, + ERR_R_INTERNAL_ERROR); + } else { + /* + * Probably we have been called from SSL_export_keying_material(), + * or SSL_export_keying_material_early(). + */ + SSLerr(SSL_F_TLS13_HKDF_EXPAND, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL); + } + EVP_PKEY_CTX_free(pctx); + return 0; + } + hashlen = EVP_MD_size(md); if (!WPACKET_init_static_len(&pkt, hkdflabel, sizeof(hkdflabel), 0) @@ -59,8 +76,11 @@ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret, || !WPACKET_finish(&pkt)) { EVP_PKEY_CTX_free(pctx); WPACKET_cleanup(&pkt); - SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, - ERR_R_INTERNAL_ERROR); + if (fatal) + SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, + ERR_R_INTERNAL_ERROR); + else + SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); return 0; } @@ -74,9 +94,13 @@ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret, EVP_PKEY_CTX_free(pctx); - if (ret != 0) - SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, - ERR_R_INTERNAL_ERROR); + if (ret != 0) { + if (fatal) + SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_HKDF_EXPAND, + ERR_R_INTERNAL_ERROR); + else + SSLerr(SSL_F_TLS13_HKDF_EXPAND, ERR_R_INTERNAL_ERROR); + } return ret == 0; } @@ -91,7 +115,7 @@ int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret, static const unsigned char keylabel[] = "key"; return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1, - NULL, 0, key, keylen); + NULL, 0, key, keylen, 1); } /* @@ -104,7 +128,7 @@ int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret, static const unsigned char ivlabel[] = "iv"; return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1, - NULL, 0, iv, ivlen); + NULL, 0, iv, ivlen, 1); } int tls13_derive_finishedkey(SSL *s, const EVP_MD *md, @@ -114,7 +138,7 @@ int tls13_derive_finishedkey(SSL *s, const EVP_MD *md, static const unsigned char finishedlabel[] = "finished"; return tls13_hkdf_expand(s, md, secret, finishedlabel, - sizeof(finishedlabel) - 1, NULL, 0, fin, finlen); + sizeof(finishedlabel) - 1, NULL, 0, fin, finlen, 1); } /* @@ -177,7 +201,7 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md, if (!tls13_hkdf_expand(s, md, prevsecret, (unsigned char *)derived_secret_label, sizeof(derived_secret_label) - 1, hash, mdlen, - preextractsec, mdlen)) { + preextractsec, mdlen, 1)) { /* SSLfatal() already called */ EVP_PKEY_CTX_free(pctx); return 0; @@ -337,7 +361,7 @@ static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md, hashlen = (size_t)hashleni; if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen, - secret, hashlen)) { + secret, hashlen, 1)) { /* SSLfatal() already called */ goto err; } @@ -517,7 +541,8 @@ int tls13_change_cipher_state(SSL *s, int which) early_exporter_master_secret, sizeof(early_exporter_master_secret) - 1, hashval, hashlen, - s->early_exporter_master_secret, hashlen)) { + s->early_exporter_master_secret, hashlen, + 1)) { SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR); goto err; @@ -604,7 +629,7 @@ int tls13_change_cipher_state(SSL *s, int which) resumption_master_secret, sizeof(resumption_master_secret) - 1, hashval, hashlen, s->resumption_master_secret, - hashlen)) { + hashlen, 1)) { /* SSLfatal() already called */ goto err; } @@ -624,7 +649,7 @@ int tls13_change_cipher_state(SSL *s, int which) exporter_master_secret, sizeof(exporter_master_secret) - 1, hash, hashlen, s->exporter_master_secret, - hashlen)) { + hashlen, 1)) { /* SSLfatal() already called */ goto err; } @@ -738,10 +763,10 @@ int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen, || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0 || !tls13_hkdf_expand(s, md, s->exporter_master_secret, (const unsigned char *)label, llen, - data, datalen, exportsecret, hashsize) + data, datalen, exportsecret, hashsize, 0) || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, sizeof(exporterlabel) - 1, hash, hashsize, - out, olen)) + out, olen, 0)) goto err; ret = 1; @@ -797,10 +822,10 @@ int tls13_export_keying_material_early(SSL *s, unsigned char *out, size_t olen, || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0 || !tls13_hkdf_expand(s, md, s->early_exporter_master_secret, (const unsigned char *)label, llen, - data, datalen, exportsecret, hashsize) + data, datalen, exportsecret, hashsize, 0) || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel, sizeof(exporterlabel) - 1, hash, hashsize, - out, olen)) + out, olen, 0)) goto err; ret = 1; |