netdev - possible integer underflow in __sctp_auth

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20120630121748.GD22767@elgon.mountain>
Date:	Sat, 30 Jun 2012 15:17:48 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Vlad Yasevich <vyasevich@...il.com>
Cc:	linux-sctp@...r.kernel.org, netdev@...r.kernel.org
Subject: possible integer underflow in __sctp_auth_cid()

In 555d3d5d "SCTP: Fix chunk acceptance when no authenticated chunks
were listed.", we added a check for if (param->param_hdr.length == 0).
Shouldn't that check be a check for if
(param->param_hdr.length < sizeos(sizeof(sctp_paramhdr_t)))?  Otherwise,
when we do the substraction on the next line we would unintentionally
end up with a high positive number.

I had a similar question about sctp_auth_ep_add_chunkid():

net/sctp/auth.c
   770          /* Check if we can add this chunk to the array */
   771          param_len = ntohs(p->param_hdr.length);
   772          nchunks = param_len - sizeof(sctp_paramhdr_t);
   773          if (nchunks == SCTP_NUM_CHUNK_TYPES)
   774                  return -EINVAL;
   775
   776          p->chunks[nchunks] = chunk_id;

If param_len is less than sizeof(sctp_paramhdr_t) we could write past
the end of the array.  There are a couple other places with this same
subtraction as well.

regards,
dan carpenter
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html