Re: [Dnsmasq-discuss] Blockdata SIGSEGV on master
On 05/09/2023 06:46, Geert Stappers wrote: On Sun, Sep 03, 2023 at 08:38:00PM +0100, Simon Kelley wrote: On 01/09/2023 20:28, Dominik Derigs wrote: Dear Simon, CC mailing list, today I've received a report of latest dnsmasq embedded into Pi-hole crashing when www.facebook.com is visited (but only when logged in). I was able to reproduce this myself after creating a (fake) account. The hit/miss ratio is not 100% but it should be possible to trigger the crash within a couple of tries. I tried Google Chrome on Linux for reproducing the crash (the report was Chrome on Windows). For this test, I used only one upstream server: 8.8.8.8 Dear list, Offline, we've found this one. The patch is in git now. It needs arbitrary RR caching to be enabled, and some fairly bad luck in what actually gets cached, but Facebook obliges every once in a while. Is it worth a next release? Soon. But note that this problem is with new code added since the last stable release, so it's not needed to fix the current stable release. Simon. Groeten Geert Stappers ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] Blockdata SIGSEGV on master
On Sun, Sep 03, 2023 at 08:38:00PM +0100, Simon Kelley wrote: > On 01/09/2023 20:28, Dominik Derigs wrote: > > Dear Simon, CC mailing list, > > > > today I've received a report of latest dnsmasq embedded into Pi-hole > > crashing when www.facebook.com is visited (but only when logged in). I > > was able to reproduce this myself after creating a (fake) account. > > > > The hit/miss ratio is not 100% but it should be possible to trigger the > > crash within a couple of tries. I tried Google Chrome on Linux for > > reproducing the crash (the report was Chrome on Windows). For this test, > > I used only one upstream server: 8.8.8.8 > > > > Dear list, > > Offline, we've found this one. The patch is in git now. It needs arbitrary > RR caching to be enabled, and some fairly bad luck in what actually gets > cached, but Facebook obliges every once in a while. Is it worth a next release? Groeten Geert Stappers -- Silence is hard to parse ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] Blockdata SIGSEGV on master
Dear list, Offline, we've found this one. The patch is in git now. It needs arbitrary RR caching to be enabled, and some fairly bad luck in what actually gets cached, but Facebook obliges every once in a while. Cheers, Simon. On 01/09/2023 20:28, Dominik Derigs wrote: Dear Simon, CC mailing list, today I've received a report of latest dnsmasq embedded into Pi-hole crashing when www.facebook.com is visited (but only when logged in). I was able to reproduce this myself after creating a (fake) account. The hit/miss ratio is not 100% but it should be possible to trigger the crash within a couple of tries. I tried Google Chrome on Linux for reproducing the crash (the report was Chrome on Windows). For this test, I used only one upstream server: 8.8.8.8 A PCAP I recorded using dumpmask=0x is attached. When the SIGSEGV happens, it can happen in a few different but related code places, let me summarize the two location I found most often below: https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blob;f=src/blockdata.c;h=444a03a6798fce5da839f199df4a9326ab17188a;hb=HEAD#l217 Thread 1 "pihole-FTL" received signal SIGSEGV, Segmentation fault. blockdata_retrieve (block=, len=13, data=0x556b98069ac0, data@entry=0x0) at /app/FTL/src/dnsmasq/blockdata.c:217 217 memcpy(d, b->key, blen); (gdb) where #0 blockdata_retrieve (block=, len=13, data=0x556b98069ac0, data@entry=0x0) at /app/FTL/src/dnsmasq/blockdata.c:217 #1 0x556b95cd2092 in answer_request (header=header@entry=0x556b9800e290, limit=limit@entry=0x556b9800e490 "", qlen=qlen@entry=31, local_addr=..., local_addr@entry=..., local_netmask=..., local_netmask@entry=..., now=now@entry=1693587354, ad_reqd=, do_bit=, have_pseudoheader=, stale=, filtered=) at /app/FTL/src/dnsmasq/rfc1035.c:2175 #2 0x556b95cac02d in receive_query (listen=listen@entry=0x556b98002d60, now=now@entry=1693587354) at /app/FTL/src/dnsmasq/forward.c:1921 #3 0x556b95c99b61 in check_dns_listeners (now=now@entry=1693587354) at /app/FTL/src/dnsmasq/dnsmasq.c:1864 #4 0x556b95c9bd2d in main_dnsmasq (argc=, argv=) at /app/FTL/src/dnsmasq/dnsmasq.c:1271 #5 0x556b95bfaf76 in main (argc=, argv=0x76ee9598) at /app/FTL/src/main.c:152 sometimes the crash happens in https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blob;f=src/blockdata.c;h=444a03a6798fce5da839f199df4a9326ab17188a;hb=HEAD#l177 Thread 1 "pihole-FTL" received signal SIGSEGV, Segmentation fault. blockdata_free (blocks=0x3368023268020600) at /app/FTL/src/dnsmasq/blockdata.c:177 177 void blockdata_free(struct blockdata *blocks) (gdb) where #0 blockdata_free (blocks=0x3368023268020600) at /app/FTL/src/dnsmasq/blockdata.c:177 #1 0x560c710c9715 in cache_scan_free (name=name@entry=0x560c7272f6d0 "star.c10r.facebook.com", addr=addr@entry=0x7ffe4bdaa9a0, class=class@entry=1, now=now@entry=1693587879, flags=flags@entry=1082130440, target_crec=target_crec@entry=0x7ffe4bdaa870, target_uid=0x7ffe4bdaa86c) at /app/FTL/src/dnsmasq/cache.c:541 #2 0x560c710cd43e in really_insert (name=0x560c7272f6d0 "star.c10r.facebook.com", addr=0x7ffe4bdaa9a0, class=1, now=1693587879, ttl=60, flags=1082130440) at /app/FTL/src/dnsmasq/cache.c:657 #3 0x560c7110aa6e in extract_addresses (header=header@entry=0x560c7273f290, qlen=, name=0x560c7272f6d0 "star.c10r.facebook.com", now=now@entry=1693587879, ipsets=ipsets@entry=0x0, nftsets=nftsets@entry=0x0, is_sign=0, check_rebind=0, no_cache_dnssec=0, secure=0, doctored=0x7ffe4bdaaa9c) at /app/FTL/src/dnsmasq/rfc1035.c:921 #4 0x560c710e39b6 in process_reply (header=header@entry=0x560c7273f290, now=now@entry=1693587879, server=0x560c7273d6d0, n=, n@entry=157, check_rebind=0, no_cache=no_cache@entry=0, cache_secure=0, bogusanswer=0, ad_reqd=0, do_bit=0, added_pheader=128, query_source=0x560c7278e150, limit=0x560c7273f760 "", ede=) at /app/FTL/src/dnsmasq/forward.c:833 #5 0x560c710e86c0 in return_reply (now=now@entry=1693587879, forward=forward@entry=0x560c7278e150, header=header@entry=0x560c7273f290, n=157, n@entry=140730171042832, status=) at /app/FTL/src/dnsmasq/forward.c:1397 #6 0x560c710e8c70 in dnssec_validate (forward=forward@entry=0x560c7278e150, header=header@entry=0x560c7273f290, plen=140730171042832, status=, status@entry=524288, now=now@entry=1693587879) at /app/FTL/src/dnsmasq/forward.c:1109 #7 0x560c710e8c1a in dnssec_validate (forward=forward@entry=0x560c72731a70, header=header@entry=0x560c7273f290, plen=plen@entry=855, status=status@entry=524288, now=now@entry=1693587879) at /app/FTL/src/dnsmasq/forward.c:1124 #8 0x560c710e9674 in reply_query (fd=, now=now@entry=1693587879) at /app/FTL/src/dnsmasq/forward.c:1319 #9 0x560c710d5dff in check_dns_listeners (now=now@entry=1693587879) at /app/FTL/src/dnsmasq/dnsmasq.c:1836 #10 0x560c710d7d2d in main_dnsmasq (argc=, argv=) at /app/FTL/src/dnsmasq/dnsmasq.c:1271 #11 0x560c71036f76 in main (argc=, argv=0x7ffe4bdab088) at
[Dnsmasq-discuss] Blockdata SIGSEGV on master
Dear Simon, CC mailing list, today I've received a report of latest dnsmasq embedded into Pi-hole crashing when www.facebook.com is visited (but only when logged in). I was able to reproduce this myself after creating a (fake) account. The hit/miss ratio is not 100% but it should be possible to trigger the crash within a couple of tries. I tried Google Chrome on Linux for reproducing the crash (the report was Chrome on Windows). For this test, I used only one upstream server: 8.8.8.8 A PCAP I recorded using dumpmask=0x is attached. When the SIGSEGV happens, it can happen in a few different but related code places, let me summarize the two location I found most often below: https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blob;f=src/blockdata.c;h=444a03a6798fce5da839f199df4a9326ab17188a;hb=HEAD#l217 Thread 1 "pihole-FTL" received signal SIGSEGV, Segmentation fault. blockdata_retrieve (block=, len=13, data=0x556b98069ac0, data@entry=0x0) at /app/FTL/src/dnsmasq/blockdata.c:217 217 memcpy(d, b->key, blen); (gdb) where #0 blockdata_retrieve (block=, len=13, data=0x556b98069ac0, data@entry=0x0) at /app/FTL/src/dnsmasq/blockdata.c:217 #1 0x556b95cd2092 in answer_request (header=header@entry=0x556b9800e290, limit=limit@entry=0x556b9800e490 "", qlen=qlen@entry=31, local_addr=..., local_addr@entry=..., local_netmask=..., local_netmask@entry=..., now=now@entry=1693587354, ad_reqd=, do_bit=, have_pseudoheader=, stale=, filtered=) at /app/FTL/src/dnsmasq/rfc1035.c:2175 #2 0x556b95cac02d in receive_query (listen=listen@entry=0x556b98002d60, now=now@entry=1693587354) at /app/FTL/src/dnsmasq/forward.c:1921 #3 0x556b95c99b61 in check_dns_listeners (now=now@entry=1693587354) at /app/FTL/src/dnsmasq/dnsmasq.c:1864 #4 0x556b95c9bd2d in main_dnsmasq (argc=, argv=) at /app/FTL/src/dnsmasq/dnsmasq.c:1271 #5 0x556b95bfaf76 in main (argc=, argv=0x76ee9598) at /app/FTL/src/main.c:152 sometimes the crash happens in https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blob;f=src/blockdata.c;h=444a03a6798fce5da839f199df4a9326ab17188a;hb=HEAD#l177 Thread 1 "pihole-FTL" received signal SIGSEGV, Segmentation fault. blockdata_free (blocks=0x3368023268020600) at /app/FTL/src/dnsmasq/blockdata.c:177 177 void blockdata_free(struct blockdata *blocks) (gdb) where #0 blockdata_free (blocks=0x3368023268020600) at /app/FTL/src/dnsmasq/blockdata.c:177 #1 0x560c710c9715 in cache_scan_free (name=name@entry=0x560c7272f6d0 "star.c10r.facebook.com", addr=addr@entry=0x7ffe4bdaa9a0, class=class@entry=1, now=now@entry=1693587879, flags=flags@entry=1082130440, target_crec=target_crec@entry=0x7ffe4bdaa870, target_uid=0x7ffe4bdaa86c) at /app/FTL/src/dnsmasq/cache.c:541 #2 0x560c710cd43e in really_insert (name=0x560c7272f6d0 "star.c10r.facebook.com", addr=0x7ffe4bdaa9a0, class=1, now=1693587879, ttl=60, flags=1082130440) at /app/FTL/src/dnsmasq/cache.c:657 #3 0x560c7110aa6e in extract_addresses (header=header@entry=0x560c7273f290, qlen=, name=0x560c7272f6d0 "star.c10r.facebook.com", now=now@entry=1693587879, ipsets=ipsets@entry=0x0, nftsets=nftsets@entry=0x0, is_sign=0, check_rebind=0, no_cache_dnssec=0, secure=0, doctored=0x7ffe4bdaaa9c) at /app/FTL/src/dnsmasq/rfc1035.c:921 #4 0x560c710e39b6 in process_reply (header=header@entry=0x560c7273f290, now=now@entry=1693587879, server=0x560c7273d6d0, n=, n@entry=157, check_rebind=0, no_cache=no_cache@entry=0, cache_secure=0, bogusanswer=0, ad_reqd=0, do_bit=0, added_pheader=128, query_source=0x560c7278e150, limit=0x560c7273f760 "", ede=) at /app/FTL/src/dnsmasq/forward.c:833 #5 0x560c710e86c0 in return_reply (now=now@entry=1693587879, forward=forward@entry=0x560c7278e150, header=header@entry=0x560c7273f290, n=157, n@entry=140730171042832, status=) at /app/FTL/src/dnsmasq/forward.c:1397 #6 0x560c710e8c70 in dnssec_validate (forward=forward@entry=0x560c7278e150, header=header@entry=0x560c7273f290, plen=140730171042832, status=, status@entry=524288, now=now@entry=1693587879) at /app/FTL/src/dnsmasq/forward.c:1109 #7 0x560c710e8c1a in dnssec_validate (forward=forward@entry=0x560c72731a70, header=header@entry=0x560c7273f290, plen=plen@entry=855, status=status@entry=524288, now=now@entry=1693587879) at /app/FTL/src/dnsmasq/forward.c:1124 #8 0x560c710e9674 in reply_query (fd=, now=now@entry=1693587879) at /app/FTL/src/dnsmasq/forward.c:1319 #9 0x560c710d5dff in check_dns_listeners (now=now@entry=1693587879) at /app/FTL/src/dnsmasq/dnsmasq.c:1836 #10 0x560c710d7d2d in main_dnsmasq (argc=, argv=) at /app/FTL/src/dnsmasq/dnsmasq.c:1271 #11 0x560c71036f76 in main (argc=, argv=0x7ffe4bdab088) at /app/FTL/src/main.c:152 Best, Dominik chrome_fb.pcap Description: application/vnd.tcpdump.pcap ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
