Messages in this thread Patch in this message | | | Date | Tue, 2 May 2006 15:40:53 +0200 | From | Ingo Molnar <> | Subject | Re: [lockup] 2.6.17-rc3: netfilter/sctp: lockup in sctp_new(), do_basic_checks() |
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* Ingo Molnar <mingo@elte.hu> wrote:
> running an "isic" stresstest on and against a testbox [which, amongst > other things, generates random incoming and outgoing packets] on > 2.6.17-rc3 (and 2.6.17-rc3-mm1) over gigabit results in a reproducible > lockup, after 5-10 minutes of runtime: > > BUG: soft lockup detected on CPU#0! > [<c0104e7f>] show_trace+0xd/0xf > [<c0104e96>] dump_stack+0x15/0x17 > [<c015ad02>] softlockup_tick+0xc5/0xd9 > [<c0134c02>] run_local_timers+0x22/0x24 > [<c0134fb7>] update_process_times+0x40/0x65 > [<c011aa56>] smp_apic_timer_interrupt+0x58/0x60 > [<c010492b>] apic_timer_interrupt+0x27/0x2c > [<c0f00df9>] sctp_new+0x8b/0x235 > [<c0ef9666>] ip_conntrack_in+0x175/0x4ca > [<c0eb6dd7>] nf_iterate+0x31/0x94 > [<c0eb6e83>] nf_hook_slow+0x49/0xda > [<c0ec2f55>] ip_rcv+0x24c/0x567 > [<c0e7dec4>] netif_receive_skb+0x34b/0x397 > [<c07870cb>] rtl8139_poll+0x3d8/0x5db > [<c0e7c7ad>] net_rx_action+0x9b/0x1ba > [<c0131955>] __do_softirq+0x6e/0xec > [<c0106187>] do_softirq+0x59/0xcd
thinking about it, what prevents the SCTP chunk's len field from being zero, and thus causing an infinite loop in for_each_sctp_chunk()? The patch below should fix that.
Ingo
---- From: Ingo Molnar <mingo@elte.hu>
fix infinite loop in the SCTP-netfilter code: check SCTP chunk size to guarantee progress of for_each_sctp_chunk(). (all other uses of for_each_sctp_chunk() are preceded by do_basic_checks(), so this fix should be complete.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Index: linux/net/ipv4/netfilter/ip_conntrack_proto_sctp.c =================================================================== --- linux.orig/net/ipv4/netfilter/ip_conntrack_proto_sctp.c +++ linux/net/ipv4/netfilter/ip_conntrack_proto_sctp.c @@ -227,6 +227,15 @@ static int do_basic_checks(struct ip_con flag = 0; for_each_sctp_chunk (skb, sch, _sch, offset, count) { + unsigned int len = (htons(sch->length) + 3) & ~3; + + /* + * Dont get into a loop with zero-sized or negative + * length values: + */ + if (!len || len >= skb->len) + goto fail; + DEBUGP("Chunk Num: %d Type: %d\n", count, sch->type); if (sch->type == SCTP_CID_INIT @@ -241,6 +250,7 @@ static int do_basic_checks(struct ip_con || sch->type == SCTP_CID_COOKIE_ECHO || flag) && count !=0 ) { +fail: DEBUGP("Basic checks failed\n"); return 1; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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