Date: Thu, 6 Aug 2020 21:51:25 +0300 From: Pavel Timofeev <timp87@gmail.com> To: ports-list freebsd <freebsd-ports@freebsd.org> Subject: Crashing net/microsocks if DNS being proxied Message-ID: <CAAoTqftaQsiUhvR9tG13QpL6Reris1B6Z1wr8srMnPDUadtFPA@mail.gmail.com>
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Hello I'd like to take advantage of net/microsocks port - a small SOCKSv5 server. It's v1.0.1 (https://github.com/rofl0r/microsocks/tree/v1.0.1) under 12.1 RELEASE amd64. It works OK with firefox until I ask firefox to proxy DNS via socks also. It cashes after getaddrinfo() call. I have quite poor C knowledge and I can't understand what's wrong with it. Parameters passed to getaddrinfo() looks OK Can anybody advise where to look at also? $ gdb92 microsocks microsocks.core GNU gdb (GDB) 9.2 [GDB v9.2 for FreeBSD] Copyright (C) 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>; This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-portbld-freebsd12.1". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from microsocks... [New LWP 100579] [New LWP 100347] Core was generated by `./microsocks'. Program terminated with signal SIGSEGV, Segmentation fault. #0 0x00000008003e5467 in _getht (hostf=0x7fffdfffd238, name=0x7fffdfffda20 "freebsd.org", pai=0x7fffdfffd5a0, cur=0x7fffdfffd240) at /usr/src/lib/libc/net/getaddrinfo.c:2476 2476 { [Current thread is 1 (LWP 100579)] (gdb) bt #0 0x00000008003e5467 in _getht (hostf=0x7fffdfffd238, name=0x7fffdfffda20 "freebsd.org", pai=0x7fffdfffd5a0, cur=0x7fffdfffd240) at /usr/src/lib/libc/net/getaddrinfo.c:2476 #1 0x00000008003e4990 in _files_getaddrinfo (rv=0x7fffdfffd670, cb_data=<optimized out>, ap=<optimized out>) at /usr/src/lib/libc/net/getaddrinfo.c:2515 #2 0x000000080040df6c in _nsdispatch (retval=0x7fffdfffd670, disp_tab=0x8004482e0, database=<optimized out>, method_name=0x8002bafb7 "getaddrinfo", defaults=<optimized out>) at /usr/src/lib/libc/net/nsdispatch.c:716 #3 0x00000008003e30b3 in explore_fqdn (pai=0x1, hostname=<optimized out>, servname=0x7fffdfffd860 "80", res=<optimized out>) at /usr/src/lib/libc/net/getaddrinfo.c:1945 #4 getaddrinfo (hostname=<optimized out>, servname=0x7fffdfffd860 "80", hints=<optimized out>, res=0x7fffdfffda18) at /usr/src/lib/libc/net/getaddrinfo.c:576 #5 0x00000000002037f6 in resolve (host=0x7fffdfffda20 "freebsd.org", port=80, addr=0x7fffdfffda18) at server.c:14 #6 0x00000000002030e8 in connect_socks_target (buf=0x7fffdfffdba0 "\005\001", n=18, client=0x800689038) at sockssrv.c:136 #7 0x00000000002029e3 in clientthread (data=0x800689030) at sockssrv.c:317 #8 0x000000080025a736 in thread_start (curthread=0x800683500) at /usr/src/lib/libthr/thread/thr_create.c:292 #9 0x0000000000000000 in ?? () Backtrace stopped: Cannot access memory at address 0x7fffdfffe000 (gdb) f 5 #5 0x00000000002037f6 in resolve (host=0x7fffdfffda20 "freebsd.org", port=80, addr=0x7fffdfffda18) at server.c:14 14 return getaddrinfo(host, port_buf, &hints, addr); (gdb) p host $1 = 0x7fffdfffda20 "freebsd.org" (gdb) p port_buf $2 = "80\000\000\b\000\000" (gdb) p hints $3 = {ai_flags = 1, ai_family = 0, ai_socktype = 1, ai_protocol = 0, ai_addrlen = 0, ai_canonname = 0x0, ai_addr = 0x0, ai_next = 0x0} (gdb) p *addr $4 = (struct addrinfo *) 0x0 (gdb) list 9 .ai_socktype = SOCK_STREAM, 10 .ai_flags = AI_PASSIVE, 11 }; 12 char port_buf[8]; 13 snprintf(port_buf, sizeof port_buf, "%u", port); 14 return getaddrinfo(host, port_buf, &hints, addr); 15 } 16 17 int server_bindtoip(const struct server *server, int fd) { 18 if(server->bindaddr.v4.sin_family != AF_UNSPEC) However, it works OK under Linux no matter if DNS proxied or not. Thank you!
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