<div dir="ltr">Please try this patch:<div><br></div><div>diff --git a/bgpd/bgp_lcommunity.c b/bgpd/bgp_lcommunity.c<br>index 15bf419868..c61684f21e 100644<br>--- a/bgpd/bgp_lcommunity.c<br>+++ b/bgpd/bgp_lcommunity.c<br>@@ -197,7 +197,7 @@ static void set_lcommunity_string(struct lcommunity *lcom, bool make_json,<br> }<br> <br> /* 1 space + lcom->size lcom strings + null terminator */<br>- size_t str_buf_sz = BUFSIZ;<br>+ size_t str_buf_sz = BUFSIZ * 10;<br> str_buf = XCALLOC(MTYPE_LCOMMUNITY_STR, str_buf_sz);<br> <br> for (i = 0; i < lcom->size; i++) {<br></div><div><br></div><div>we are creating a string that is not big enough for the community. We need to look at this a bit more precisely than my multiplication by 10</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Apr 20, 2023 at 10:33 AM mike tancsa <<a href="mailto:mike@sentex.net">mike@sentex.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On 4/20/2023 9:30 AM, mike tancsa wrote:<br>
> On 4/18/2023 5:28 AM, Kurt Jaeger wrote:<br>
>> Hi!<br>
>><br>
>>> This caused bgpd to terminate on several boxes this morning:<br>
>>><br>
>>> 2023/04/18 08:43:47 BGP: bgpd/bgp_lcommunity.c:236: <br>
>>> set_lcommunity_string(): assertion ((unsigned int)len < str_buf_sz) <br>
>>> failed<br>
>>> BGP: Received signal 6 at 1681800227 (si_addr 0x0); aborting...<br>
>>><br>
>>> OS: FreeBSD 13.1p3. frr was 8.4.x and 8.5. So someone is sending<br>
>>> strange things... ?<br>
>>><br>
>>> 7.5.1 is not affected...<br>
>>><br>
>>> Any ideas on how to avoid the assert ?<br>
>> There's the lookup for community aliases added in that function:<br>
>><br>
>> const char *com2alias =<br>
>> translate_alias ? bgp_community2alias(lcsb) <br>
>> : lcsb;<br>
>> len = strlcat(str_buf, com2alias, str_buf_sz);<br>
>><br>
>> and it seems to trigger the issue.<br>
><br>
><br>
> I am seeing this crash as well. Sadly the patch in the freebsd pr does <br>
> not seem to work around the issue. If its an issue of communities, is <br>
> there an easy way to strip out communities from peers for now ?<br>
><br>
Adding some debugging. It seems to be a large community that is bigger <br>
than 1024 bytes. Looking at the pcap,<br>
<br>
<br>
09:27:57.240613 IP (tos 0xc0, ttl 1, id 22455, offset 0, flags [DF], <br>
proto TCP (6), length 1500)<br>
192.168.158.77.179 > 192.168.158.78.64274: Flags [.], cksum 0x96a5 <br>
(correct), seq 4567154:4568614, ack 964, win 31913, length 1460: BGP [|BGP]<br>
Update Message (2), length: 81<br>
Origin (1), length: 1, Flags [T]: IGP<br>
AS Path (2), length: 18, Flags [T]: 174 45758 55808 147027<br>
Next Hop (3), length: 4, Flags [T]: 192.168.158.77<br>
Multi Exit Discriminator (4), length: 4, Flags [O]: 64070<br>
Community (8), length: 8, Flags [OT]: 174:21001, 174:22013<br>
Updated routes:<br>
<a href="http://110.164.235.0/24" rel="noreferrer" target="_blank">110.164.235.0/24</a><br>
<a href="http://110.164.234.0/24" rel="noreferrer" target="_blank">110.164.234.0/24</a><br>
Update Message (2), length: 1021<br>
Origin (1), length: 1, Flags [T]: IGP<br>
AS Path (2), length: 22, Flags [T]: 174 3491 60068 983 38136<br>
Next Hop (3), length: 4, Flags [T]: 192.168.158.77<br>
Multi Exit Discriminator (4), length: 4, Flags [O]: 15030<br>
Community (8), length: 8, Flags [OT]: 174:21000, 174:22013<br>
Large Community (32), length: 936, Flags [OTE]:<br>
4635:0:0, 4635:1:906, 4635:1:2906, 4635:1:4515, <br>
4635:1:4594, 4635:1:4641, 4635:1:4760, 4635:1:7979, 4635:1:9253, <br>
4635:1:9293, 4635:1:9304, 4635:1:9908, 4635:1:13335, 4635:1:16265, <br>
4635:1:17924, 4635:1:18013, 4635:1:20940, 4635:1:22822, 4635:1:24429, <br>
4635:1:24482, 4635:1:32590, 4635:1:32934, 4635:1:36692, 4635:1:38008, <br>
4635:1:38819, 4635:1:41378, 4635:1:45753, 4635:1:46489, 4635:1:49544, <br>
4635:1:51847, 4635:1:54574, 4635:1:54994, 4635:1:55720, 4635:1:56059, <br>
4635:1:57724, 4635:1:65021, 4635:1:134823, 4635:1:136907, 4635:1:146961, <br>
24115:0:24115, 24115:1:906, 24115:1:2906, 24115:1:4515, 24115:1:4594, <br>
24115:1:4641, 24115:1:4760, 24115:1:7979, 24115:1:9253, 24115:1:9293, <br>
24115:1:9304, 24115:1:9908, 24115:1:13335, 24115:1:16265, 24115:1:17924, <br>
24115:1:18013, 24115:1:20940, 24115:1:22822, 24115:1:24429, <br>
24115:1:24482, 24115:1:32590, 24115:1:32934, 24115:1:36692, <br>
24115:1:38008, 24115:1:38819, 24115:1:41378, 24115:1:45753, <br>
24115:1:46489, 24115:1:49544, 24115:1:51847, 24115:1:54574, <br>
24115:1:54994, 24115:1:55720, 24115:1:56059, 24115:1:57724, <br>
24115:1:65021, 24115:1:134823, 24115:1:136907, 24115:1:146961<br>
Updated routes:<br>
<a href="http://103.135.103.0/24" rel="noreferrer" target="_blank">103.135.103.0/24</a><br>
Update Message (2), length: 77<br>
Origin (1), length: 1, Flags [T]: IGP<br>
AS Path (2), length: 18, Flags [T]: 174 262589 14259 16921<br>
Next Hop (3), length: 4, Flags [T]: 192.168.158.77<br>
Multi Exit Discriminator (4), length: 4, Flags [O]: 48050<br>
Community (8), length: 8, Flags [OT]: 174:21001, 174:22013<br>
Updated routes:<br>
<a href="http://200.108.121.0/24" rel="noreferrer" target="_blank">200.108.121.0/24</a><br>
Update Message (2), length: 73<br>
Origin (1), length: 1, Flags [T]: IGP<br>
AS Path (2), length: 14, Flags [T]: 174 1239 54174<br>
Next Hop (3), length: 4, Flags [T]: 192.168.158.77<br>
Multi Exit Discriminator (4), length: 4, Flags [O]: 15030<br>
Community (8), length: 8, Flags [OT]: 174:21000, 174:22013<br>
Updated routes:<br>
<a href="http://208.21.37.0/24" rel="noreferrer" target="_blank">208.21.37.0/24</a><br>
Update Message (2), length: 81<br>
Origin (1), length: 1, Flags [T]: IGP<br>
AS Path (2), length: 22, Flags [T]: 174 1299 6939 6939 398704<br>
Next Hop (3), length: 4, Flags [T]: 192.168.158.77<br>
Multi Exit Discriminator (4), length: 4, Flags [O]: 1<br>
Community (8), length: 8, Flags [OT]: 174:21000, 174:22003<br>
Updated routes:<br>
<a href="http://205.198.124.0/24" rel="noreferrer" target="_blank">205.198.124.0/24</a><br>
<br>
With some added debugging, it seems its exceeding the size of the buffer<br>
zlog_warn("set_lcommunity_string: str_buf_sz=%lu [%s] [%s]\n", <br>
str_buf_sz, lcsb, str_buf);<br>
<br>
Apr 20 10:02:25 cogent-2023 bgpd[43237]: [SH1YD-SM74V] <br>
set_lcommunity_string: str_buf_sz=1024 [24115:1:136907] [4635:0:0 <br>
4635:1:906 4635:1:2906 4635:1:4515 4635:1:4594 4635:1:4641 4635:1:4760 <br>
4635:1:7979 4635:1:9253 4635:1:9293 4635:1:93<br>
04 4635:1:9908 4635:1:13335 4635:1:16265 4635:1:17924 4635:1:18013 <br>
4635:1:20940 4635:1:22822 4635:1:24429 4635:1:24482 4635:1:32590 <br>
4635:1:32934 4635:1:36692 4635:1:38008 4635:1:38819 4635:1:41378 <br>
4635:1:45753 4635:1:46489 4635:1:49544 4<br>
635:1:51847 4635:1:54574 4635:1:54994 4635:1:55720 4635:1:56059 <br>
4635:1:57724 4635:1:65021 4635:1:134823 4635:1:136907 4635:1:146961 <br>
24115:0:24115 24115:1:906 24115:1:2906 24115:1:4515 24115:1:4594 <br>
24115:1:4641 24115:1:4760 24115:1:7979 2<br>
4115:1:9253 24115:1:9293 24115:1:9304 24115:1:9908 24115:1:13335 <br>
24115:1:16265 24115:1:17924 24115:1:18013 24115:1:20940 24115:1:22822 <br>
24115:1:24429 24115:1:24482 24115:1:32590 24115:1:32934 24115:1:36692 <br>
24115:1:38008 24115:1:38819 2411<br>
5:1:41378 24115:1:45753 24115:1:46489 24115:1:49544 24115:1:51847 <br>
24115:1:54574 24115:1:54994 24115:1:55720 24115:1:56059 24115:1:57724 <br>
24115:1:65021 24115:1:134823 ]<br>
Apr 20 10:02:25 cogent-2023 bgpd[43237]: [SH1YD-SM74V] <br>
set_lcommunity_string: str_buf_sz=1024 [24115:1:146961] [4635:0:0 <br>
4635:1:906 4635:1:2906 4635:1:4515 4635:1:4594 4635:1:4641 4635:1:4760 <br>
4635:1:7979 4635:1:9253 4635:1:9293 4635:1:93<br>
04 4635:1:9908 4635:1:13335 4635:1:16265 4635:1:17924 4635:1:18013 <br>
4635:1:20940 4635:1:22822 4635:1:24429 4635:1:24482 4635:1:32590 <br>
4635:1:32934 4635:1:36692 4635:1:38008 4635:1:38819 4635:1:41378 <br>
4635:1:45753 4635:1:46489 4635:1:49544 4<br>
635:1:51847 4635:1:54574 4635:1:54994 4635:1:55720 4635:1:56059 <br>
4635:1:57724 4635:1:65021 4635:1:134823 4635:1:136907 4635:1:146961 <br>
24115:0:24115 24115:1:906 24115:1:2906 24115:1:4515 24115:1:4594 <br>
24115:1:4641 24115:1:4760 24115:1:7979 2<br>
4115:1:9253 24115:1:9293 24115:1:9304 24115:1:9908 24115:1:13335 <br>
24115:1:16265 24115:1:17924 24115:1:18013 24115:1:20940 24115:1:22822 <br>
24115:1:24429 24115:1:24482 24115:1:32590 24115:1:32934 24115:1:36692 <br>
24115:1:38008 24115:1:38819 2411<br>
5:1:41378 24115:1:45753 24115:1:46489 24115:1:49544 24115:1:51847 <br>
24115:1:54574 24115:1:54994 24115:1:55720 24115:1:56059 24115:1:57724 <br>
24115:1:65021 24115:1:134823 24115:1:136907 ]<br>
Apr 20 10:02:25 cogent-2023 bgpd[43237]: bgpd/bgp_lcommunity.c:239: <br>
set_lcommunity_string(): assertion ((unsigned int)len < str_buf_sz) failed<br>
<br>
<br>
<br>
<br>
_______________________________________________<br>
dev mailing list<br>
<a href="mailto:dev@lists.frrouting.org" target="_blank">dev@lists.frrouting.org</a><br>
<a href="https://lists.frrouting.org/listinfo/dev" rel="noreferrer" target="_blank">https://lists.frrouting.org/listinfo/dev</a><br>
</blockquote></div>