Description of problem: Using SSH port forwarding for mail transfers, large mails abort it. Version-Release number of selected component (if applicable): openssh-4.7p1-1.fc8 Fixed by a downgrade to: openssh-4.5p1-6.fc7 remote: openssh-3.1p1-14.3.legacy.i386 (RHEL 7.3) How reproducible: It was reproducible on one specific mail, I expect it would be easily reproducible again. Steps to Reproduce: 1. ssh -v -t -R 2852:127.0.0.1:852 REMOTE sleep-command specifically: ssh -v -t -L 2525:127.0.0.1:25 -R 2852:127.0.0.1:852 -R 2022:127.0.0.1:22 paulina.vellum.cz 'while :;do echo -n .;sleep 1m;done';sleep 1m;done 2. Start transfer at the REMOTE host to port 2852. Actual results: local ssh: debug1: channel 3: new [127.0.0.1] debug1: confirm forwarded-tcpip debug3: channel 3: waiting for connection debug1: channel 3: connected ...debug2: channel 3: window 935334 sent adjust 1161818 debug2: channel 3: window 966656 sent adjust 1130496 buffer_get_string_ret: bad string length 557056 buffer_get_string: buffer error custom transfer app: DIE: Got 1724408 out of the required 6377714 bytes local ssh strace: select(10, [3 4 5 6 9], [], NULL, {60, 0}) = 1 (in [3], left {59, 909000}) read(3, "\324\20\200\37#0\301\345<\220\211\20W\274$Wl\35|\260\251d\262q\30)\17\5\271\204\311\230"..., 8192) = 1448 brk(0x2aaaaad36000) = 0x2aaaaacfd000 mmap(NULL, 1048576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2aaaae039000 mmap(NULL, 692224, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2aaaae139000 write(2, "buffer_get_string_ret: bad strin"..., 49) = 49 write(2, "buffer_get_string: buffer error\r"..., 33) = 33 ioctl(0, SNDCTL_TMR_STOP or TCSETSW, {B38400 opost isig icanon echo ...}) = 0 exit_group(255) = ? Expected results: Seamless transfers as with the older F7 openssh. Additional info: So far not tried to debug it. Not tried against newer SSH server.
Created attachment 192601 [details] Full SSH client output
I've put your bug into upstream bugzilla here: https://bugzilla.mindrot.org/show_bug.cgi?id=1360 Can you please provide the needed info which Damien Miller asks for? You don't have to create account to that bugzilla if you don't want to, I'll put a comment there as soon as you attach it here.
Created attachment 197761 [details] Workaround - undo one patch of the version upgrade. Details are being discussed upstream.
Comment 3 undoes (I hope) the change: - markus.org 2007/06/11 09:14:00 [channels.h] increase default channel windows; ok djm