From: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Date: Sun, 7 Feb 2010 20:20:28 +0000 (+0000)
Subject: dccp: allow probing of CCID-array length
X-Git-Tag: v2.6.34-rc1~233^2~377
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69a6a0b38a139ccceef32222108caca8a9b0b795;p=pandora-kernel.git

dccp: allow probing of CCID-array length

This fixes a problem in the DCCP getsockopt() API: currently there is no way
for a user to a priori know the number of built-in CCIDs, other than trying
DCCP_SOCKOPT_AVAILABLE_CCIDS in a loop, incrementing the option length until
EINVAL is no longer returned.

This patch truncates the array to the user-provided length. No copy is made
when the length is <= 0.

Due to the length restriction in do_dccp_getsockopt() to sizeof(int), the
minimum array length remains 4, which is a reasonable default (only 3
CCIDs, CCID-2..4, are currently defined).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
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