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Question SYSERR: Write to socket: Connection reset by peer

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23 Jan 2018 11:46 #7429 by cunning
Guys, i just went through a years worth of core i had, but it was not easy. I also did see this crash 3x last year. I suspected a buffer overflow as well. I have yet to dig into that one because of my normal every day job. Now that i see its more of an issue, I will dig into this a little more.


I had that same issue with Aliases. Once an alias was over 256 characters it corrupted the entire ASCII chain of aliases. I had to go back to the get_line() limit of 256 and noticed that we could handle 512 characters in the buffers we had local.

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23 Jan 2018 19:23 - 23 Jan 2018 19:24 #7433 by Treblin
Here is the requested output:
Code:
(gdb) up #1 0x00326a89 in free () from /lib/libc.so.6 (gdb) up #2 0x0809d541 in close_socket (d=0x938cf70) at comm.c:2094 2094 free(d->history[cnt]); (gdb) print *d $1 = {descriptor = 154734240, host = "p!A", '\000' <repeats 37 times>, bad_pws = 0 '\000', idle_tics = 0 '\000', connected = 32, desc_num = 6, login_time = 1516187435, showstr_head = 0x0, showstr_vector = 0x0, showstr_count = 0, showstr_page = 0, str = 0x0, backstr = 0x0, max_str = 0, mail_to = 0, has_prompt = 0, inbuf = "\000ET http://www.boxun.com/ HTTP/1.1\r\nHost: www.boxun.com\r\nConne ction: keep-alive\r\nAccept-Encoding: gzip, deflate\r\nAccept: */*\r\nUser-Agent : Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML,"..., last_input = "User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537. 36 (KHTML, like Gecko)", '\000' <repeats 425 times>, small_outbuf = "Attempting to Detect Client, Please Wait...\r\n\377\375\030Col lecting Protocol Information... Please Wait.\r\n", '\000' <repeats 926 times>, output = 0x93901d0 "Attempting to Detect Client, Please Wait...\r\n\377\375\03 0Collecting Protocol Information... Please Wait.\r\n", history = 0x8bde4b0, history_pos = 1, bufptr = 97, bufspace = 926, large_outbuf = 0x0, input = { head = 0x0, tail = 0x9390c88}, character = 0x0, original = 0x0, snooping = 0x0, snoop_by = 0x0, next = 0x0, olc = 0x0, pProtocol = 0x9390ea8, events = 0x9390a30} (gdb) print d->history[0] $2 = 0x9390b00 ".1" (gdb) print d->history[1] $3 = 0x9390b08 "(\v9\t: www.boxun.com" (gdb) print d->history[2] $4 = 0x9390b48 "p\v9\tection: keep-alive" (gdb) print d->history[3] $5 = 0x9390b98 "\310\v9\tpt-Encoding: gzip, deflate" (gdb) print d->history[4] $6 = 0x9390bf8 "\200\f9\tpt: */*" (gdb) print d->output $7 = 0x93901d0 "Attempting to Detect Client, Please Wait...\r\n\377\375\030Collecting Protocol Information... Please Wait.\r\n"
Last edit: 23 Jan 2018 19:24 by Treblin.

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23 Jan 2018 21:00 #7435 by thomas
Ok, some observations:

Nothing in this code is overflowing.
d->history[] is totally messed up. I can recognize the contents as http headers, though the first 4 bytes of each is garbage.

The first four bytes of d->history[1] are 0x28 0x0b 0x39 0x09, or the byte representation of 0x9390b28.

Please run the command
x/40xb 0x9390b28.

This should list out memory contents at that location. It might provide a clue...

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23 Jan 2018 21:58 #7436 by Treblin
Code:
#0 0x003223d0 in _int_free () from /lib/libc.so.6 (gdb) up #1 0x00326a89 in free () from /lib/libc.so.6 (gdb) up #2 0x0809d541 in close_socket (d=0x938cf70) at comm.c:2094 2094 free(d->history[cnt]); (gdb) x/40xb 0x9390b28 0x9390b28: 0x68 0x0b 0x39 0x09 0x19 0x00 0x00 0x00 0x9390b30: 0x00 0x00 0x00 0x00 0x3a 0x20 0x77 0x77 0x9390b38: 0x77 0x2e 0x62 0x6f 0x78 0x75 0x6e 0x2e 0x9390b40: 0x63 0x6f 0x6d 0x00 0x21 0x00 0x00 0x00 0x9390b48: 0x70 0x0b 0x39 0x09 0x65 0x63 0x74 0x69

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04 Feb 2018 18:42 #7537 by JTP
Any luck find out why it crashes with some connections ?

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05 Feb 2018 22:13 #7540 by Treblin
Not sure if Thomas has had any luck tracking it down. Luckily this hasn't been a prevalent issue at least for myself. I've had it happen just the one time.

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