Andrei Pelinescu-Onciul wrote: > On Nov 12, 2009 at 11:29, Vlad Yasevich <vladislav.yasevich@xxxxxx> wrote: >> >> Andrei Pelinescu-Onciul wrote: >>> When setting the autoclose timeout in jiffies there is a possible >>> integer overflow if the value in seconds is very large >>> (e.g. for 2^22 s with HZ=1024). The problem appears even on >>> 64-bit due to the integer promotion rules. The fix is just a cast >>> to unsigned long. >>> >>> Signed-off-by: Andrei Pelinescu-Onciul <andrei@xxxxxxxxx> >>> --- >>> net/sctp/associola.c | 2 +- >>> 1 files changed, 1 insertions(+), 1 deletions(-) >>> >>> diff --git a/net/sctp/associola.c b/net/sctp/associola.c >>> index 525864b..7f69f4d 100644 >>> --- a/net/sctp/associola.c >>> +++ b/net/sctp/associola.c >>> @@ -166,7 +166,7 @@ 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] = >>> - sp->autoclose * HZ; >>> + (unsigned long)sp->autoclose * HZ; >>> >>> /* Initilizes the timers */ >>> for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) >> This becomes unnecessary with Patch 3. > > I don't think so. Patch 3 makes sure > sp->autoclose <= (MAX_SCHEDULE_TIMEOUT / HZ). > On 64 bits this is always true, because autoclose is u32, > MAX_SCHEDULE_TIMEOUT is LONG_MAX (2^63-1) and HZ <= 1024, so on 64 bits > patch 3 will not do anything and sp->autoclose * HZ can still overflow > an int. > E.g.: autoclose= 2^22, HZ=1024. > 2^22 < (2^63-1)/1024 => patch 3 does not change autoclose > However 2^22 * 1024 = 2^32 which is > UINT_MAX => > asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] will be set to > (uint)2^32 = 0! > Ok. So, we'll change patch 3 to do: if (sp->autoclose * HZ > MAX_SCHEDULE_TIMEOUT) sp->autoclose = MAX_SCHEDULE_TIMEOUT/HZ; -vlad > > Andrei > > ------------------------------------------------------------------------------ > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day > trial. Simplify your report design, integration and deployment - and focus on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > _______________________________________________ > Lksctp-developers mailing list > Lksctp-developers@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/lksctp-developers > -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
