diff --git a/src/openvpn/ntlm.c b/src/openvpn/ntlm.c index 2e77214151f..2b735ecda35 100644 --- a/src/openvpn/ntlm.c +++ b/src/openvpn/ntlm.c @@ -167,8 +167,13 @@ unicodize(char *dst, const char *src) static void add_security_buffer(int sb_offset, void *data, int length, - unsigned char *msg_buf, int *msg_bufpos) + unsigned char *msg_buf, int *msg_bufpos, size_t msg_bufsize) { + if (*msg_bufpos + length > msg_bufsize) + { + msg(M_WARN, "NTLM: security buffer too big for message buffer"); + return; + } /* Adds security buffer data to a message and sets security buffer's * offset and length */ msg_buf[sb_offset] = (unsigned char)length; @@ -396,20 +401,20 @@ ntlm_phase_3(const struct http_proxy_info *p, const char *phase_2, if (ntlmv2_enabled) /* NTLMv2 response */ { add_security_buffer(0x14, ntlmv2_response, ntlmv2_blob_size + 16, - phase3, &phase3_bufpos); + phase3, &phase3_bufpos, sizeof(phase3)); } else /* NTLM response */ { - add_security_buffer(0x14, ntlm_response, 24, phase3, &phase3_bufpos); + add_security_buffer(0x14, ntlm_response, 24, phase3, &phase3_bufpos, sizeof(phase3)); } /* username in ascii */ add_security_buffer(0x24, username, strlen(username), phase3, - &phase3_bufpos); + &phase3_bufpos, sizeof(phase3)); /* Set domain. If is empty, default domain will be used * (i.e. proxy's domain) */ - add_security_buffer(0x1c, domain, strlen(domain), phase3, &phase3_bufpos); + add_security_buffer(0x1c, domain, strlen(domain), phase3, &phase3_bufpos, sizeof(phase3)); /* other security buffers will be empty */ phase3[0x10] = phase3_bufpos; /* lm not used */