alistair23-linux/net/sctp/sysctl.c
Neil Horman 3c68198e75 sctp: Make hmac algorithm selection for cookie generation dynamic
Currently sctp allows for the optional use of md5 of sha1 hmac algorithms to
generate cookie values when establishing new connections via two build time
config options.  Theres no real reason to make this a static selection.  We can
add a sysctl that allows for the dynamic selection of these algorithms at run
time, with the default value determined by the corresponding crypto library
availability.
This comes in handy when, for example running a system in FIPS mode, where use
of md5 is disallowed, but SHA1 is permitted.

Note: This new sysctl has no corresponding socket option to select the cookie
hmac algorithm.  I chose not to implement that intentionally, as RFC 6458
contains no option for this value, and I opted not to pollute the socket option
namespace.

Change notes:
v2)
	* Updated subject to have the proper sctp prefix as per Dave M.
	* Replaced deafult selection options with new options that allow
	  developers to explicitly select available hmac algs at build time
	  as per suggestion by Vlad Y.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-26 02:22:18 -04:00

385 lines
9.3 KiB
C

/* SCTP kernel implementation
* (C) Copyright IBM Corp. 2002, 2004
* Copyright (c) 2002 Intel Corp.
*
* This file is part of the SCTP kernel implementation
*
* Sysctl related interfaces for SCTP.
*
* This SCTP implementation is free software;
* you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This SCTP implementation is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* ************************
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <lksctp-developers@lists.sourceforge.net>
*
* Or submit a bug report through the following website:
* http://www.sf.net/projects/lksctp
*
* Written or modified by:
* Mingqin Liu <liuming@us.ibm.com>
* Jon Grimm <jgrimm@us.ibm.com>
* Ardelle Fan <ardelle.fan@intel.com>
* Ryan Layer <rmlayer@us.ibm.com>
* Sridhar Samudrala <sri@us.ibm.com>
*
* Any bugs reported given to us we will try to fix... any fixes shared will
* be incorporated into the next SCTP release.
*/
#include <net/sctp/structs.h>
#include <net/sctp/sctp.h>
#include <linux/sysctl.h>
static int zero = 0;
static int one = 1;
static int timer_max = 86400000; /* ms in one day */
static int int_max = INT_MAX;
static int sack_timer_min = 1;
static int sack_timer_max = 500;
static int addr_scope_max = 3; /* check sctp_scope_policy_t in include/net/sctp/constants.h for max entries */
static int rwnd_scale_max = 16;
static unsigned long max_autoclose_min = 0;
static unsigned long max_autoclose_max =
(MAX_SCHEDULE_TIMEOUT / HZ > UINT_MAX)
? UINT_MAX : MAX_SCHEDULE_TIMEOUT / HZ;
extern long sysctl_sctp_mem[3];
extern int sysctl_sctp_rmem[3];
extern int sysctl_sctp_wmem[3];
static int proc_sctp_do_hmac_alg(ctl_table *ctl,
int write,
void __user *buffer, size_t *lenp,
loff_t *ppos);
static ctl_table sctp_table[] = {
{
.procname = "sctp_mem",
.data = &sysctl_sctp_mem,
.maxlen = sizeof(sysctl_sctp_mem),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax
},
{
.procname = "sctp_rmem",
.data = &sysctl_sctp_rmem,
.maxlen = sizeof(sysctl_sctp_rmem),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "sctp_wmem",
.data = &sysctl_sctp_wmem,
.maxlen = sizeof(sysctl_sctp_wmem),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ /* sentinel */ }
};
static ctl_table sctp_net_table[] = {
{
.procname = "rto_initial",
.data = &init_net.sctp.rto_initial,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &timer_max
},
{
.procname = "rto_min",
.data = &init_net.sctp.rto_min,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &timer_max
},
{
.procname = "rto_max",
.data = &init_net.sctp.rto_max,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &timer_max
},
{
.procname = "rto_alpha_exp_divisor",
.data = &init_net.sctp.rto_alpha,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = proc_dointvec,
},
{
.procname = "rto_beta_exp_divisor",
.data = &init_net.sctp.rto_beta,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = proc_dointvec,
},
{
.procname = "max_burst",
.data = &init_net.sctp.max_burst,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &int_max
},
{
.procname = "cookie_preserve_enable",
.data = &init_net.sctp.cookie_preserve_enable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "cookie_hmac_alg",
.maxlen = 8,
.mode = 0644,
.proc_handler = proc_sctp_do_hmac_alg,
},
{
.procname = "valid_cookie_life",
.data = &init_net.sctp.valid_cookie_life,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &timer_max
},
{
.procname = "sack_timeout",
.data = &init_net.sctp.sack_timeout,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &sack_timer_min,
.extra2 = &sack_timer_max,
},
{
.procname = "hb_interval",
.data = &init_net.sctp.hb_interval,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &timer_max
},
{
.procname = "association_max_retrans",
.data = &init_net.sctp.max_retrans_association,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &int_max
},
{
.procname = "path_max_retrans",
.data = &init_net.sctp.max_retrans_path,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &int_max
},
{
.procname = "max_init_retransmits",
.data = &init_net.sctp.max_retrans_init,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &int_max
},
{
.procname = "pf_retrans",
.data = &init_net.sctp.pf_retrans,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &int_max
},
{
.procname = "sndbuf_policy",
.data = &init_net.sctp.sndbuf_policy,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "rcvbuf_policy",
.data = &init_net.sctp.rcvbuf_policy,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "default_auto_asconf",
.data = &init_net.sctp.default_auto_asconf,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "addip_enable",
.data = &init_net.sctp.addip_enable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "addip_noauth_enable",
.data = &init_net.sctp.addip_noauth,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "prsctp_enable",
.data = &init_net.sctp.prsctp_enable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "auth_enable",
.data = &init_net.sctp.auth_enable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "addr_scope_policy",
.data = &init_net.sctp.scope_policy,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &zero,
.extra2 = &addr_scope_max,
},
{
.procname = "rwnd_update_shift",
.data = &init_net.sctp.rwnd_upd_shift,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.extra1 = &one,
.extra2 = &rwnd_scale_max,
},
{
.procname = "max_autoclose",
.data = &init_net.sctp.max_autoclose,
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = &proc_doulongvec_minmax,
.extra1 = &max_autoclose_min,
.extra2 = &max_autoclose_max,
},
{ /* sentinel */ }
};
static int proc_sctp_do_hmac_alg(ctl_table *ctl,
int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
char tmp[8];
ctl_table tbl;
int ret;
int changed = 0;
char *none = "none";
memset(&tbl, 0, sizeof(struct ctl_table));
if (write) {
tbl.data = tmp;
tbl.maxlen = 8;
} else {
tbl.data = net->sctp.sctp_hmac_alg ? : none;
tbl.maxlen = strlen(tbl.data);
}
ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
if (write) {
#ifdef CONFIG_CRYPTO_MD5
if (!strncmp(tmp, "md5", 3)) {
net->sctp.sctp_hmac_alg = "md5";
changed = 1;
}
#endif
#ifdef CONFIG_CRYPTO_SHA1
if (!strncmp(tmp, "sha1", 4)) {
net->sctp.sctp_hmac_alg = "sha1";
changed = 1;
}
#endif
if (!strncmp(tmp, "none", 4)) {
net->sctp.sctp_hmac_alg = NULL;
changed = 1;
}
if (!changed)
ret = -EINVAL;
}
return ret;
}
int sctp_sysctl_net_register(struct net *net)
{
struct ctl_table *table;
int i;
table = kmemdup(sctp_net_table, sizeof(sctp_net_table), GFP_KERNEL);
if (!table)
return -ENOMEM;
for (i = 0; table[i].data; i++)
table[i].data += (char *)(&net->sctp) - (char *)&init_net.sctp;
net->sctp.sysctl_header = register_net_sysctl(net, "net/sctp", table);
return 0;
}
void sctp_sysctl_net_unregister(struct net *net)
{
unregister_net_sysctl_table(net->sctp.sysctl_header);
}
static struct ctl_table_header * sctp_sysctl_header;
/* Sysctl registration. */
void sctp_sysctl_register(void)
{
sctp_sysctl_header = register_net_sysctl(&init_net, "net/sctp", sctp_table);
}
/* Sysctl deregistration. */
void sctp_sysctl_unregister(void)
{
unregister_net_sysctl_table(sctp_sysctl_header);
}