sctp: fix incorrect overflow check on autoclose

Commit 8ffd3208 voids the previous patches f6778aab and 810c0719 for
limiting the autoclose value.  If userspace passes in -1 on 32-bit
platform, the overflow check didn't work and autoclose would be set
to 0xffffffff.

This patch defines a max_autoclose (in seconds) for limiting the value
and exposes it through sysctl, with the following intentions.

1) Avoid overflowing autoclose * HZ.

2) Keep the default autoclose bound consistent across 32- and 64-bit
   platforms (INT_MAX / HZ in this patch).

3) Keep the autoclose value consistent between setsockopt() and
   getsockopt() calls.

Suggested-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Xi Wang 2011-12-16 12:44:15 +00:00 committed by David S. Miller
parent 2ca6cf06d9
commit 2692ba61a8
5 changed files with 21 additions and 3 deletions

View File

@ -241,6 +241,9 @@ extern struct sctp_globals {
* bits is an indicator of when to send and window update SACK.
*/
int rwnd_update_shift;
/* Threshold for autoclose timeout, in seconds. */
unsigned long max_autoclose;
} sctp_globals;
#define sctp_rto_initial (sctp_globals.rto_initial)
@ -281,6 +284,7 @@ extern struct sctp_globals {
#define sctp_auth_enable (sctp_globals.auth_enable)
#define sctp_checksum_disable (sctp_globals.checksum_disable)
#define sctp_rwnd_upd_shift (sctp_globals.rwnd_update_shift)
#define sctp_max_autoclose (sctp_globals.max_autoclose)
/* SCTP Socket type: UDP or TCP style. */
typedef enum {

View File

@ -173,7 +173,7 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
asoc->timeouts[SCTP_EVENT_TIMEOUT_HEARTBEAT] = 0;
asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
(unsigned long)sp->autoclose * HZ;
min_t(unsigned long, sp->autoclose, sctp_max_autoclose) * HZ;
/* Initializes the timers */
for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)

View File

@ -1285,6 +1285,9 @@ SCTP_STATIC __init int sctp_init(void)
sctp_max_instreams = SCTP_DEFAULT_INSTREAMS;
sctp_max_outstreams = SCTP_DEFAULT_OUTSTREAMS;
/* Initialize maximum autoclose timeout. */
sctp_max_autoclose = INT_MAX / HZ;
/* Initialize handle used for association ids. */
idr_init(&sctp_assocs_id);

View File

@ -2200,8 +2200,6 @@ static int sctp_setsockopt_autoclose(struct sock *sk, char __user *optval,
return -EINVAL;
if (copy_from_user(&sp->autoclose, optval, optlen))
return -EFAULT;
/* make sure it won't exceed MAX_SCHEDULE_TIMEOUT */
sp->autoclose = min_t(long, sp->autoclose, MAX_SCHEDULE_TIMEOUT / HZ);
return 0;
}

View File

@ -53,6 +53,10 @@ 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];
@ -258,6 +262,15 @@ static ctl_table sctp_table[] = {
.extra1 = &one,
.extra2 = &rwnd_scale_max,
},
{
.procname = "max_autoclose",
.data = &sctp_max_autoclose,
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = &proc_doulongvec_minmax,
.extra1 = &max_autoclose_min,
.extra2 = &max_autoclose_max,
},
{ /* sentinel */ }
};