* gnu/packages/patches/ssh.scm (libssh2)[source]: Add patch. * gnu/packages/patches/libssh2-CVE-2019-17498.patch: New file. * gnu/local.mk (dist_patch_DATA): Register it.
		
			
				
	
	
		
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			5.4 KiB
		
	
	
	
		
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			126 lines
		
	
	
	
		
			5.4 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
https://github.com/libssh2/libssh2/commit/dedcbd106f8e52d5586b0205bc7677e4c9868f9c.patch
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From dedcbd106f8e52d5586b0205bc7677e4c9868f9c Mon Sep 17 00:00:00 2001
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From: Will Cosgrove <will@panic.com>
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Date: Fri, 30 Aug 2019 09:57:38 -0700
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Subject: [PATCH] packet.c: improve message parsing (#402)
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* packet.c: improve parsing of packets
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file: packet.c
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notes:
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Use _libssh2_get_string API in SSH_MSG_DEBUG/SSH_MSG_DISCONNECT. Additional uint32 bounds check in SSH_MSG_GLOBAL_REQUEST.
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---
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 src/packet.c | 68 ++++++++++++++++++++++------------------------------
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 1 file changed, 29 insertions(+), 39 deletions(-)
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diff --git a/src/packet.c b/src/packet.c
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index 38ab62944..2e01bfc5d 100644
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--- a/src/packet.c
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+++ b/src/packet.c
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@@ -419,8 +419,8 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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                     size_t datalen, int macstate)
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 {
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     int rc = 0;
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-    char *message = NULL;
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-    char *language = NULL;
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+    unsigned char *message = NULL;
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+    unsigned char *language = NULL;
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     size_t message_len = 0;
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     size_t language_len = 0;
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     LIBSSH2_CHANNEL *channelp = NULL;
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@@ -472,33 +472,23 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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         case SSH_MSG_DISCONNECT:
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             if(datalen >= 5) {
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-                size_t reason = _libssh2_ntohu32(data + 1);
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+                uint32_t reason = 0;
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+                struct string_buf buf;
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+                buf.data = (unsigned char *)data;
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+                buf.dataptr = buf.data;
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+                buf.len = datalen;
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+                buf.dataptr++; /* advance past type */
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-                if(datalen >= 9) {
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-                    message_len = _libssh2_ntohu32(data + 5);
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+                _libssh2_get_u32(&buf, &reason);
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+                _libssh2_get_string(&buf, &message, &message_len);
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+                _libssh2_get_string(&buf, &language, &language_len);
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-                    if(message_len < datalen-13) {
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-                        /* 9 = packet_type(1) + reason(4) + message_len(4) */
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-                        message = (char *) data + 9;
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-
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-                        language_len =
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-                            _libssh2_ntohu32(data + 9 + message_len);
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-                        language = (char *) data + 9 + message_len + 4;
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-
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-                        if(language_len > (datalen-13-message_len)) {
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-                            /* bad input, clear info */
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-                            language = message = NULL;
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-                            language_len = message_len = 0;
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-                        }
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-                    }
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-                    else
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-                        /* bad size, clear it */
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-                        message_len = 0;
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-                }
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                 if(session->ssh_msg_disconnect) {
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-                    LIBSSH2_DISCONNECT(session, reason, message,
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-                                       message_len, language, language_len);
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+                    LIBSSH2_DISCONNECT(session, reason, (const char *)message,
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+                                       message_len, (const char *)language,
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+                                       language_len);
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                 }
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+
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                 _libssh2_debug(session, LIBSSH2_TRACE_TRANS,
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                                "Disconnect(%d): %s(%s)", reason,
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                                message, language);
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@@ -539,24 +529,24 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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                 int always_display = data[1];
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                 if(datalen >= 6) {
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-                    message_len = _libssh2_ntohu32(data + 2);
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-
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-                    if(message_len <= (datalen - 10)) {
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-                        /* 6 = packet_type(1) + display(1) + message_len(4) */
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-                        message = (char *) data + 6;
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-                        language_len = _libssh2_ntohu32(data + 6 +
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-                                                        message_len);
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-
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-                        if(language_len <= (datalen - 10 - message_len))
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-                            language = (char *) data + 10 + message_len;
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-                    }
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+                    struct string_buf buf;
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+                    buf.data = (unsigned char *)data;
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+                    buf.dataptr = buf.data;
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+                    buf.len = datalen;
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+                    buf.dataptr += 2; /* advance past type & always display */
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+
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+                    _libssh2_get_string(&buf, &message, &message_len);
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+                    _libssh2_get_string(&buf, &language, &language_len);
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                 }
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                 if(session->ssh_msg_debug) {
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-                    LIBSSH2_DEBUG(session, always_display, message,
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-                                  message_len, language, language_len);
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+                    LIBSSH2_DEBUG(session, always_display,
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+                                  (const char *)message,
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+                                  message_len, (const char *)language,
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+                                  language_len);
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                 }
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             }
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+
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             /*
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              * _libssh2_debug will actually truncate this for us so
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              * that it's not an inordinate about of data
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@@ -579,7 +569,7 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
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                 uint32_t len = 0;
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                 unsigned char want_reply = 0;
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                 len = _libssh2_ntohu32(data + 1);
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-                if(datalen >= (6 + len)) {
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+                if((len <= (UINT_MAX - 6)) && (datalen >= (6 + len))) {
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                     want_reply = data[5 + len];
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                     _libssh2_debug(session,
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                                    LIBSSH2_TRACE_CONN,
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