tree 04e24f2b012c14f33f5bc3d6f96f84056cf1fbbe
parent 7455a76f170f794498d26081a5f15b797ef1a2aa
author Gerrit Renker <gerrit@erg.abdn.ac.uk> 1265574028 +0000
committer David S. Miller <davem@davemloft.net> 1266004020 -0800

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>