diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c index db68bed5fe..0b3e87d2b8 100644 --- a/ssl/s3_clnt.c +++ b/ssl/s3_clnt.c @@ -2652,7 +2652,11 @@ int ssl3_send_client_key_exchange(SSL *s) #ifndef OPENSSL_NO_PSK else if (alg_k & SSL_kPSK) { - char identity[PSK_MAX_IDENTITY_LEN]; + /* The callback needs PSK_MAX_IDENTITY_LEN + 1 bytes + * to return a \0-terminated identity. The last byte + * is for us for simulating strnlen. */ + char identity[PSK_MAX_IDENTITY_LEN + 2]; + size_t identity_len; unsigned char *t = NULL; unsigned char psk_or_pre_ms[PSK_MAX_PSK_LEN*2+4]; unsigned int pre_ms_len = 0, psk_len = 0; @@ -2666,8 +2670,9 @@ int ssl3_send_client_key_exchange(SSL *s) goto err; } + memset(identity, 0, sizeof(identity)); psk_len = s->psk_client_callback(s, s->ctx->psk_identity_hint, - identity, PSK_MAX_IDENTITY_LEN, + identity, sizeof(identity) - 1, psk_or_pre_ms, sizeof(psk_or_pre_ms)); if (psk_len > PSK_MAX_PSK_LEN) { @@ -2681,7 +2686,14 @@ int ssl3_send_client_key_exchange(SSL *s) SSL_R_PSK_IDENTITY_NOT_FOUND); goto psk_err; } - + identity[PSK_MAX_IDENTITY_LEN + 1] = '\0'; + identity_len = strlen(identity); + if (identity_len > PSK_MAX_IDENTITY_LEN) + { + SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, + ERR_R_INTERNAL_ERROR); + goto psk_err; + } /* create PSK pre_master_secret */ pre_ms_len = 2+psk_len+2+psk_len; t = psk_or_pre_ms; @@ -2715,14 +2727,13 @@ int ssl3_send_client_key_exchange(SSL *s) s->session->master_key_length = s->method->ssl3_enc->generate_master_secret(s, s->session->master_key, - psk_or_pre_ms, pre_ms_len); - n = strlen(identity); - s2n(n, p); - memcpy(p, identity, n); - n+=2; + psk_or_pre_ms, pre_ms_len); + s2n(identity_len, p); + memcpy(p, identity, identity_len); + n = 2 + identity_len; psk_err = 0; psk_err: - OPENSSL_cleanse(identity, PSK_MAX_IDENTITY_LEN); + OPENSSL_cleanse(identity, sizeof(identity)); OPENSSL_cleanse(psk_or_pre_ms, sizeof(psk_or_pre_ms)); if (psk_err != 0) {