On 2017-04-02 14:45, Florian Westphal wrote:
Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
- for (i = sizeof(struct tcphdr); i <= tcp_hdrlen - TCPOLEN_MSS; i +=
optlen(opt, i)) {
+ for (i = sizeof(struct tcphdr); i < tcp_hdrlen - TCPOLEN_MSS; i +=
optlen(opt, i)) {
if (opt[i] == TCPOPT_MSS && opt[i+1] == TCPOLEN_MSS) {
u_int16_t oldmss;
maybe I am low on caffeeine but this looks fine, for tcp header with
only tcpmss this boils down to "20 <= 24 - 4" so we acccess offsets
20-23 which seems ok.
It seems some non-standard(or corrupted) packets are passing, because
even on ~1G server it might cause corruption once per several days,
KASAN seems need less time to trigger.
I am not aware how things working, but:
[25181.875696] Memory state around the buggy address:
[25181.875919] ffff8802975fff80: 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00
[25181.876275] ffff880297600000: 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00
[25181.876628] >ffff880297600080: 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00
[25181.876984]
^
[25181.877203] ffff880297600100: 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00
[25181.877569] ffff880297600180: 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00
Why all data here is zero? I guess it should be some packet data?
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