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[DCCP]: set safe upper bound for option length 

This is a re-send from
http://www.mail-archive.com/dccp@vger.kernel.org/msg00553.html

It is the same patch as before, but I have built in Arnaldo's suggestions
pointed out in that posting.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
This commit is contained in:
Gerrit Renker 2006-11-10 02:13:56 -02:00 committed by David S. Miller
parent 931731123a
commit 60361be1be
1 changed files with 12 additions and 6 deletions
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18
net/dccp/dccp.h
View File

@ -40,12 +40,18 @@ extern void dccp_tw_deschedule(struct inet_timewait_sock *tw);
extern void dccp_time_wait(struct sock *sk, int state, int timeo);
/* FIXME: Right size this */
#define DCCP_MAX_OPT_LEN 128
#define DCCP_MAX_PACKET_HDR 32
#define MAX_DCCP_HEADER (DCCP_MAX_PACKET_HDR + DCCP_MAX_OPT_LEN + MAX_HEADER)
/*
* Set safe upper bounds for header and option length. Since Data Offset is 8
* bits (RFC 4340, sec. 5.1), the total header length can never be more than
* 4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
* - DCCP-Response with ACK Subheader and 4 bytes of Service code OR
* - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields
* Hence a safe upper bound for the maximum option length is 1020-28 = 992
*/
#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
#define DCCP_MAX_PACKET_HDR 28
#define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
#define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
* state, about 60 seconds */