On 20/01/17 13:10, Marcelo Ricardo Leitner wrote:
> On Fri, Jan 20, 2017 at 01:01:57PM +0000, Colin King wrote:
>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>
>> The comparison on the timeout can lead to an array overrun
>> read on sctp_timer_tbl because of an off-by-one error. Fix
>> this by using < instead of <= and also compare to the array
>> size rather than SCTP_EVENT_TIMEOUT_MAX.
>>
>> Fixes CoverityScan CID#1397639 ("Out-of-bounds read")
>>
>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>> ---
>> net/sctp/debug.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/sctp/debug.c b/net/sctp/debug.c
>> index 95d7b15..e371a0d 100644
>> --- a/net/sctp/debug.c
>> +++ b/net/sctp/debug.c
>> @@ -166,7 +166,7 @@ static const char *const sctp_timer_tbl[] = {
>> /* Lookup timer debug name. */
>> const char *sctp_tname(const sctp_subtype_t id)
>> {
>> - if (id.timeout <= SCTP_EVENT_TIMEOUT_MAX)
>> + if (id.timeout < ARRAY_SIZE(sctp_timer_tbl))
>> return sctp_timer_tbl[id.timeout];
>
> The issue exists but this is not the right fix.
> Issue was introduced by 7b9438de0cd4 ("sctp: add stream reconf timer")
> as it introduced a new timer but didn't add the timer name here, so the
> fix should (also) include:
>
> diff --git a/net/sctp/debug.c b/net/sctp/debug.c
> index 95d7b15dad21..c5f4ed5242ac 100644
> --- a/net/sctp/debug.c
> +++ b/net/sctp/debug.c
> @@ -159,6 +159,7 @@ static const char *const sctp_timer_tbl[] = {
> "TIMEOUT_T4_RTO",
> "TIMEOUT_T5_SHUTDOWN_GUARD",
> "TIMEOUT_HEARTBEAT",
> + "TIMEOUT_RECONF",
> "TIMEOUT_SACK",
> "TIMEOUT_AUTOCLOSE",
> };
Ah, OK, I can add that timeout into the the table, but perhaps it's
still prudent to check the index against the table size as well.
>
> Thanks,
> Marcelo
>
>> return "unknown_timer";
>> }
>> --
>> 2.10.2
>>
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