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>
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 6b39529..60ffbd0 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -53,6 +53,10 @@
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 @@
.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 */ }
};