From a021de2aabb21a24c7b69aaae1c710a9b6fee429 Mon Sep 17 00:00:00 2001 From: Frank Lichtenheld Date: Wed, 17 Jan 2024 09:59:51 +0100 Subject: [PATCH] NTLM: add length check to add_security_buffer Especially ntlmv2_response can be very big, so make sure we not do exceed the size of the phase3 buffer. Change-Id: Icea931d29e3e504e23e045539b21013b42172664 Signed-off-by: Frank Lichtenheld Acked-by: Gert Doering Message-Id: <20240117085951.27414-1-gert@greenie.muc.de> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg28037.html Signed-off-by: Gert Doering --- src/openvpn/ntlm.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/src/openvpn/ntlm.c b/src/openvpn/ntlm.c index bc33f414a..99d4ae7a5 100644 --- a/src/openvpn/ntlm.c +++ b/src/openvpn/ntlm.c @@ -154,8 +154,13 @@ 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; @@ -362,15 +367,15 @@ ntlm_phase_3(const struct http_proxy_info *p, const char *phase_2, /* NTLMv2 response */ add_security_buffer(0x14, ntlmv2_response, ntlmv2_blob_size + 16, - phase3, &phase3_bufpos); + 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 */ -- 2.39.2