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linux/net/sctp/sysctl.c
Firo Yang da05cecc49 sctp: sysctl: make extra pointers netns aware 
Recently, a customer reported that from their container whose
net namespace is different to the host's init_net, they can't set
the container's net.sctp.rto_max to any value smaller than
init_net.sctp.rto_min.

For instance,
Host:
sudo sysctl net.sctp.rto_min
net.sctp.rto_min = 1000

Container:
echo 100 > /mnt/proc-net/sctp/rto_min
echo 400 > /mnt/proc-net/sctp/rto_max
echo: write error: Invalid argument

This is caused by the check made from this'commit 4f3fdf3bc5
("sctp: add check rto_min and rto_max in sysctl")'
When validating the input value, it's always referring the boundary
value set for the init_net namespace.

Having container's rto_max smaller than host's init_net.sctp.rto_min
does make sense. Consider that the rto between two containers on the
same host is very likely smaller than it for two hosts.

So to fix this problem, as suggested by Marcelo, this patch makes the
extra pointers of rto_min, rto_max, pf_retrans, and ps_retrans point
to the corresponding variables from the newly created net namespace while
the new net namespace is being registered in sctp_sysctl_net_register.

Fixes: 4f3fdf3bc5 ("sctp: add check rto_min and rto_max in sysctl")
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Firo Yang <firo.yang@suse.com>
Link: https://lore.kernel.org/r/20221209054854.23889-1-firo.yang@suse.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-12 12:57:29 -08:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/* 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.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <linux-sctp@vger.kernel.org>
*
* 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>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <net/sctp/structs.h>
#include <net/sctp/sctp.h>
#include <linux/sysctl.h>
static int timer_max = 86400000; /* ms in one day */
static int sack_timer_min = 1;
static int sack_timer_max = 500;
static int addr_scope_max = SCTP_SCOPE_POLICY_MAX;
static int rwnd_scale_max = 16;
static int rto_alpha_min = 0;
static int rto_beta_min = 0;
static int rto_alpha_max = 1000;
static int rto_beta_max = 1000;
static int pf_expose_max = SCTP_PF_EXPOSE_MAX;
static int ps_retrans_max = SCTP_PS_RETRANS_MAX;
static int udp_port_max = 65535;
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;
static int proc_sctp_do_hmac_alg(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos);
static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos);
static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write, void *buffer,
size_t *lenp, loff_t *ppos);
static int proc_sctp_do_udp_port(struct ctl_table *ctl, int write, void *buffer,
size_t *lenp, loff_t *ppos);
static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos);
static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos);
static int proc_sctp_do_probe_interval(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos);
static struct 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 */ }
};
/* The following index defines are used in sctp_sysctl_net_register().
* If you add new items to the sctp_net_table, please ensure that
* the index values of these defines hold the same meaning indicated by
* their macro names when they appear in sctp_net_table.
*/
#define SCTP_RTO_MIN_IDX 0
#define SCTP_RTO_MAX_IDX 1
#define SCTP_PF_RETRANS_IDX 2
#define SCTP_PS_RETRANS_IDX 3
static struct ctl_table sctp_net_table[] = {
[SCTP_RTO_MIN_IDX] = {
.procname = "rto_min",
.data = &init_net.sctp.rto_min,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_sctp_do_rto_min,
.extra1 = SYSCTL_ONE,
.extra2 = &init_net.sctp.rto_max
},
[SCTP_RTO_MAX_IDX] = {
.procname = "rto_max",
.data = &init_net.sctp.rto_max,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_sctp_do_rto_max,
.extra1 = &init_net.sctp.rto_min,
.extra2 = &timer_max
},
[SCTP_PF_RETRANS_IDX] = {
.procname = "pf_retrans",
.data = &init_net.sctp.pf_retrans,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = &init_net.sctp.ps_retrans,
},
[SCTP_PS_RETRANS_IDX] = {
.procname = "ps_retrans",
.data = &init_net.sctp.ps_retrans,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &init_net.sctp.pf_retrans,
.extra2 = &ps_retrans_max,
},
{
.procname = "rto_initial",
.data = &init_net.sctp.rto_initial,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
.extra2 = &timer_max
},
{
.procname = "rto_alpha_exp_divisor",
.data = &init_net.sctp.rto_alpha,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_sctp_do_alpha_beta,
.extra1 = &rto_alpha_min,
.extra2 = &rto_alpha_max,
},
{
.procname = "rto_beta_exp_divisor",
.data = &init_net.sctp.rto_beta,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_sctp_do_alpha_beta,
.extra1 = &rto_beta_min,
.extra2 = &rto_beta_max,
},
{
.procname = "max_burst",
.data = &init_net.sctp.max_burst,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_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",
.data = &init_net.sctp.sctp_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 = SYSCTL_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 = SYSCTL_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 = SYSCTL_ONE,
.extra2 = SYSCTL_INT_MAX,
},
{
.procname = "path_max_retrans",
.data = &init_net.sctp.max_retrans_path,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
.extra2 = SYSCTL_INT_MAX,
},
{
.procname = "max_init_retransmits",
.data = &init_net.sctp.max_retrans_init,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
.extra2 = SYSCTL_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 = "reconf_enable",
.data = &init_net.sctp.reconf_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_sctp_do_auth,
},
{
.procname = "intl_enable",
.data = &init_net.sctp.intl_enable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "ecn_enable",
.data = &init_net.sctp.ecn_enable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "plpmtud_probe_interval",
.data = &init_net.sctp.probe_interval,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_sctp_do_probe_interval,
},
{
.procname = "udp_port",
.data = &init_net.sctp.udp_port,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_sctp_do_udp_port,
.extra1 = SYSCTL_ZERO,
.extra2 = &udp_port_max,
},
{
.procname = "encap_port",
.data = &init_net.sctp.encap_port,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = &udp_port_max,
},
{
.procname = "addr_scope_policy",
.data = &init_net.sctp.scope_policy,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_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 = SYSCTL_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,
},
#ifdef CONFIG_NET_L3_MASTER_DEV
{
.procname = "l3mdev_accept",
.data = &init_net.sctp.l3mdev_accept,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#endif
{
.procname = "pf_enable",
.data = &init_net.sctp.pf_enable,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "pf_expose",
.data = &init_net.sctp.pf_expose,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = &pf_expose_max,
},
{ /* sentinel */ }
};
static int proc_sctp_do_hmac_alg(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
struct ctl_table tbl;
bool changed = false;
char *none = "none";
char tmp[8] = {0};
int ret;
memset(&tbl, 0, sizeof(struct ctl_table));
if (write) {
tbl.data = tmp;
tbl.maxlen = sizeof(tmp);
} else {
tbl.data = net->sctp.sctp_hmac_alg ? : none;
tbl.maxlen = strlen(tbl.data);
}
ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
if (write && ret == 0) {
#ifdef CONFIG_CRYPTO_MD5
if (!strncmp(tmp, "md5", 3)) {
net->sctp.sctp_hmac_alg = "md5";
changed = true;
}
#endif
#ifdef CONFIG_CRYPTO_SHA1
if (!strncmp(tmp, "sha1", 4)) {
net->sctp.sctp_hmac_alg = "sha1";
changed = true;
}
#endif
if (!strncmp(tmp, "none", 4)) {
net->sctp.sctp_hmac_alg = NULL;
changed = true;
}
if (!changed)
ret = -EINVAL;
}
return ret;
}
static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
unsigned int min = *(unsigned int *) ctl->extra1;
unsigned int max = *(unsigned int *) ctl->extra2;
struct ctl_table tbl;
int ret, new_value;
memset(&tbl, 0, sizeof(struct ctl_table));
tbl.maxlen = sizeof(unsigned int);
if (write)
tbl.data = &new_value;
else
tbl.data = &net->sctp.rto_min;
ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
if (write && ret == 0) {
if (new_value > max || new_value < min)
return -EINVAL;
net->sctp.rto_min = new_value;
}
return ret;
}
static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
unsigned int min = *(unsigned int *) ctl->extra1;
unsigned int max = *(unsigned int *) ctl->extra2;
struct ctl_table tbl;
int ret, new_value;
memset(&tbl, 0, sizeof(struct ctl_table));
tbl.maxlen = sizeof(unsigned int);
if (write)
tbl.data = &new_value;
else
tbl.data = &net->sctp.rto_max;
ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
if (write && ret == 0) {
if (new_value > max || new_value < min)
return -EINVAL;
net->sctp.rto_max = new_value;
}
return ret;
}
static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
if (write)
pr_warn_once("Changing rto_alpha or rto_beta may lead to "
"suboptimal rtt/srtt estimations!\n");
return proc_dointvec_minmax(ctl, write, buffer, lenp, ppos);
}
static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
struct ctl_table tbl;
int new_value, ret;
memset(&tbl, 0, sizeof(struct ctl_table));
tbl.maxlen = sizeof(unsigned int);
if (write)
tbl.data = &new_value;
else
tbl.data = &net->sctp.auth_enable;
ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
if (write && ret == 0) {
struct sock *sk = net->sctp.ctl_sock;
net->sctp.auth_enable = new_value;
/* Update the value in the control socket */
lock_sock(sk);
sctp_sk(sk)->ep->auth_enable = new_value;
release_sock(sk);
}
return ret;
}
static int proc_sctp_do_udp_port(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
unsigned int min = *(unsigned int *)ctl->extra1;
unsigned int max = *(unsigned int *)ctl->extra2;
struct ctl_table tbl;
int ret, new_value;
memset(&tbl, 0, sizeof(struct ctl_table));
tbl.maxlen = sizeof(unsigned int);
if (write)
tbl.data = &new_value;
else
tbl.data = &net->sctp.udp_port;
ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
if (write && ret == 0) {
struct sock *sk = net->sctp.ctl_sock;
if (new_value > max || new_value < min)
return -EINVAL;
net->sctp.udp_port = new_value;
sctp_udp_sock_stop(net);
if (new_value) {
ret = sctp_udp_sock_start(net);
if (ret)
net->sctp.udp_port = 0;
}
/* Update the value in the control socket */
lock_sock(sk);
sctp_sk(sk)->udp_port = htons(net->sctp.udp_port);
release_sock(sk);
}
return ret;
}
static int proc_sctp_do_probe_interval(struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct net *net = current->nsproxy->net_ns;
struct ctl_table tbl;
int ret, new_value;
memset(&tbl, 0, sizeof(struct ctl_table));
tbl.maxlen = sizeof(unsigned int);
if (write)
tbl.data = &new_value;
else
tbl.data = &net->sctp.probe_interval;
ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
if (write && ret == 0) {
if (new_value && new_value < SCTP_PROBE_TIMER_MIN)
return -EINVAL;
net->sctp.probe_interval = new_value;
}
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;
table[SCTP_RTO_MIN_IDX].extra2 = &net->sctp.rto_max;
table[SCTP_RTO_MAX_IDX].extra1 = &net->sctp.rto_min;
table[SCTP_PF_RETRANS_IDX].extra2 = &net->sctp.ps_retrans;
table[SCTP_PS_RETRANS_IDX].extra1 = &net->sctp.pf_retrans;
net->sctp.sysctl_header = register_net_sysctl(net, "net/sctp", table);
if (net->sctp.sysctl_header == NULL) {
kfree(table);
return -ENOMEM;
}
return 0;
}
void sctp_sysctl_net_unregister(struct net *net)
{
struct ctl_table *table;
table = net->sctp.sysctl_header->ctl_table_arg;
unregister_net_sysctl_table(net->sctp.sysctl_header);
kfree(table);
}
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);
}
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