From b9aa7c2495694d0527e4e7fd560a3f0f18556c72 Mon Sep 17 00:00:00 2001
From: Will Cosgrove <will@panic.com>
Date: Thu, 29 Aug 2019 15:14:19 -0700
Subject: [PATCH 1/5] packet.c: improve parsing of packets
file: packet.c
notes:
Use _libssh2_get_string API in SSH_MSG_DEBUG, additional uint32 bounds check in SSH_MSG_GLOBAL_REQUEST
---
src/packet.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/src/packet.c b/src/packet.c
index 38ab6294..ac69768c 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -537,26 +537,26 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
case SSH_MSG_DEBUG:
if(datalen >= 2) {
int always_display = data[1];
-
+
if(datalen >= 6) {
- message_len = _libssh2_ntohu32(data + 2);
-
- if(message_len <= (datalen - 10)) {
- /* 6 = packet_type(1) + display(1) + message_len(4) */
- message = (char *) data + 6;
- language_len = _libssh2_ntohu32(data + 6 +
- message_len);
-
- if(language_len <= (datalen - 10 - message_len))
- language = (char *) data + 10 + message_len;
- }
+ struct string_buf buf;
+ buf.data = (unsigned char *)data;
+ buf.dataptr = buf.data;
+ buf.len = datalen;
+ buf.dataptr += 2; /* advance past type & always display */
+
+ _libssh2_get_string(&buf, &message, &message_len);
+ _libssh2_get_string(&buf, &language, &language_len);
}
if(session->ssh_msg_debug) {
- LIBSSH2_DEBUG(session, always_display, message,
- message_len, language, language_len);
+ LIBSSH2_DEBUG(session, always_display,
+ (const char *)message,
+ message_len, (const char *)language,
+ language_len);
}
}
+
/*
* _libssh2_debug will actually truncate this for us so
* that it's not an inordinate about of data
@@ -579,7 +579,7 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
uint32_t len = 0;
unsigned char want_reply = 0;
len = _libssh2_ntohu32(data + 1);
- if(datalen >= (6 + len)) {
+ if((len <= (UINT_MAX - 6) && (datalen >= (6 + len))) {
want_reply = data[5 + len];
_libssh2_debug(session,
LIBSSH2_TRACE_CONN,
From 8b3cf0b17c1b84a138bed9423a9e0743452b4de9 Mon Sep 17 00:00:00 2001
From: Will Cosgrove <will@panic.com>
Date: Thu, 29 Aug 2019 15:15:33 -0700
Subject: [PATCH 2/5] stray whitespace
---
src/packet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/packet.c b/src/packet.c
index ac69768c..8908b2c5 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -537,7 +537,7 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
case SSH_MSG_DEBUG:
if(datalen >= 2) {
int always_display = data[1];
-
+
if(datalen >= 6) {
struct string_buf buf;
buf.data = (unsigned char *)data;
From 1c6fa92b77e34d089493fe6d3e2c6c8775858b94 Mon Sep 17 00:00:00 2001
From: Will Cosgrove <will@panic.com>
Date: Thu, 29 Aug 2019 15:24:22 -0700
Subject: [PATCH 3/5] fixed type issue, updated SSH_MSG_DISCONNECT
SSH_MSG_DISCONNECT now also uses _libssh2_get API.
---
src/packet.c | 40 +++++++++++++++-------------------------
1 file changed, 15 insertions(+), 25 deletions(-)
diff --git a/src/packet.c b/src/packet.c
index 8908b2c5..97f0cdd4 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -419,8 +419,8 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
size_t datalen, int macstate)
{
int rc = 0;
- char *message = NULL;
- char *language = NULL;
+ unsigned char *message = NULL;
+ unsigned char *language = NULL;
size_t message_len = 0;
size_t language_len = 0;
LIBSSH2_CHANNEL *channelp = NULL;
@@ -472,33 +472,23 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
case SSH_MSG_DISCONNECT:
if(datalen >= 5) {
- size_t reason = _libssh2_ntohu32(data + 1);
+ uint32_t reason = 0;
+ struct string_buf buf;
+ buf.data = (unsigned char *)data;
+ buf.dataptr = buf.data;
+ buf.len = datalen;
+ buf.dataptr++; /* advance past type */
- if(datalen >= 9) {
- message_len = _libssh2_ntohu32(data + 5);
+ _libssh2_get_u32(&buf, &reason);
+ _libssh2_get_string(&buf, &message, &message_len);
+ _libssh2_get_string(&buf, &language, &language_len);
- if(message_len < datalen-13) {
- /* 9 = packet_type(1) + reason(4) + message_len(4) */
- message = (char *) data + 9;
-
- language_len =
- _libssh2_ntohu32(data + 9 + message_len);
- language = (char *) data + 9 + message_len + 4;
-
- if(language_len > (datalen-13-message_len)) {
- /* bad input, clear info */
- language = message = NULL;
- language_len = message_len = 0;
- }
- }
- else
- /* bad size, clear it */
- message_len = 0;
- }
if(session->ssh_msg_disconnect) {
- LIBSSH2_DISCONNECT(session, reason, message,
- message_len, language, language_len);
+ LIBSSH2_DISCONNECT(session, reason, (const char *)message,
+ message_len, (const char *)language,
+ language_len);
}
+
_libssh2_debug(session, LIBSSH2_TRACE_TRANS,
"Disconnect(%d): %s(%s)", reason,
message, language);
From 77616117cc9dbbdd0fe1157098435bff73a83a0f Mon Sep 17 00:00:00 2001
From: Will Cosgrove <will@panic.com>
Date: Thu, 29 Aug 2019 15:26:32 -0700
Subject: [PATCH 4/5] fixed stray (
bad paste
---
src/packet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/packet.c b/src/packet.c
index 97f0cdd4..bd4c39e4 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -569,7 +569,7 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
uint32_t len = 0;
unsigned char want_reply = 0;
len = _libssh2_ntohu32(data + 1);
- if((len <= (UINT_MAX - 6) && (datalen >= (6 + len))) {
+ if(len <= (UINT_MAX - 6) && datalen >= (6 + len)) {
want_reply = data[5 + len];
_libssh2_debug(session,
LIBSSH2_TRACE_CONN,
From 436c45dc143cadc8c59afac6c4255be332856581 Mon Sep 17 00:00:00 2001
From: Will Cosgrove <will@panic.com>
Date: Thu, 29 Aug 2019 15:29:00 -0700
Subject: [PATCH 5/5] added additional parentheses for clarity
---
src/packet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/packet.c b/src/packet.c
index bd4c39e4..2e01bfc5 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -569,7 +569,7 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
uint32_t len = 0;
unsigned char want_reply = 0;
len = _libssh2_ntohu32(data + 1);
- if(len <= (UINT_MAX - 6) && datalen >= (6 + len)) {
+ if((len <= (UINT_MAX - 6)) && (datalen >= (6 + len))) {
want_reply = data[5 + len];
_libssh2_debug(session,
LIBSSH2_TRACE_CONN,
