From 2692ba61a82203404abd7dd2a027bda962861f74 Mon Sep 17 00:00:00 2001 From: Xi Wang Date: Fri, 16 Dec 2011 12:44:15 +0000 Subject: [PATCH] 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 Signed-off-by: Xi Wang Signed-off-by: David S. Miller --- include/net/sctp/structs.h | 4 ++++ net/sctp/associola.c | 2 +- net/sctp/protocol.c | 3 +++ net/sctp/socket.c | 2 -- net/sctp/sysctl.c | 13 +++++++++++++ 5 files changed, 21 insertions(+), 3 deletions(-) diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index e90e7a9935dd..a15432da27c3 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -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 { diff --git a/net/sctp/associola.c b/net/sctp/associola.c index 152b5b3c3fff..acd2edbc073e 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -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) diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index 61b9fca5a173..6f6ad8686833 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -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); diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 13bf5fcdbff1..54a7cd2fdd7a 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -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; } diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c index 6b3952961b85..60ffbd067ff7 100644 --- a/net/sctp/sysctl.c +++ b/net/sctp/sysctl.c @@ -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 */ } }; -- GitLab