OpenSSH Security Advisory (adv.channelalloc)

From: Markus Friedl (markusat_private)
Date: Thu Mar 07 2002 - 03:56:33 PST

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    1. Systems affected:
    
    	All versions of OpenSSH between 2.0 and 3.0.2 contain
    	an off-by-one error in the channel code.
    
    	OpenSSH 3.1 and later are not affected.
    
    2. Impact:
    
            This bug can be exploited locally by an authenticated user
            logging into a vulnerable OpenSSH server or by a malicious
            SSH server attacking a vulnerable OpenSSH client.
    	
    3. Solution:
    
    	Upgrade to OpenSSH 3.1 or apply the following patch.
    
    4. Credits:
    
    	This bug was discovered by Joost Pol <joostat_private>
    
    
    Appendix:
    
    Index: channels.c
    ===================================================================
    RCS file: /cvs/src/usr.bin/ssh/channels.c,v
    retrieving revision 1.170
    retrieving revision 1.171
    diff -u -r1.170 -r1.171
    --- channels.c	27 Feb 2002 21:23:13 -0000	1.170
    +++ channels.c	4 Mar 2002 19:37:58 -0000	1.171
    @@ -146,7 +146,7 @@
     {
     	Channel *c;
     
    -	if (id < 0 || id > channels_alloc) {
    +	if (id < 0 || id >= channels_alloc) {
     		log("channel_lookup: %d: bad id", id);
     		return NULL;
     	}
    



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