openssh bugs - Jun 2022 - [Bug 3454] New: client dies with exit code 141 (SIGPIPE) when ControlMaster times out during mux_client_hello_exchange()

https://bugzilla.mindrot.org/show_bug.cgi?id=3454

            Bug ID: 3454
           Summary: client dies with exit code 141 (SIGPIPE) when
                    ControlMaster times out during
                    mux_client_hello_exchange()
           Product: Portable OpenSSH
           Version: 8.9p1
          Hardware: amd64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P5
         Component: ssh
          Assignee: unassigned-bugs at mindrot.org
          Reporter: noamlewis+openssh-bugzilla at google.com

If the client tries to start talking to a ControlMaster just as it's
exiting (due to ControlPersist timeout), it will fail with exit code
141 (SIGPIPE).

To reproduce:

( while true; do \
  sleep 0.5 ; \
  gdb -ex r -ex q --args \
    ssh -o ControlMaster=auto \
        -o ControlPath=~/.ssh/elsa-ctrl-%C \
        -o ControlPersist=1 127.0.0.1 -- touch /tmp/thingy ; \
  done )


(You might need to fiddle with the sleep time)

Program received signal SIGPIPE, Broken pipe.
0x00007ffff7b38f33 in __GI___libc_write (fd=fd at entry=3,
buf=buf at entry=0x55555565e060, nbytes=nbytes at entry=12) at
../sysdeps/unix/sysv/linux/write.c:26

(gdb) bt
#0  0x00007ffff7b38f33 in __GI___libc_write (fd=fd at entry=3,
buf=buf at entry=0x55555565e060, nbytes=nbytes at entry=12) at
../sysdeps/unix/sysv/linux/write.c:26
#1  0x0000555555583380 in mux_client_write_packet (fd=fd at entry=3,
m=m at entry=0x55555565deb0) at ../../mux.c:1513
#2  0x0000555555585944 in mux_client_hello_exchange (fd=3) at
../../mux.c:1589
#3  muxclient (path=0x55555565ba60
"/home/noamlewis/.ssh/elsa-ctrl-cfbf228b3cff12162e33cbe54c12340af8f78155")
at ../../mux.c:2297
#4  0x0000555555561882 in main (ac=<optimized out>, av=<optimized
out>)
at ../../ssh.c:1526


Reproduces also with older clients (8.4)

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https://bugzilla.mindrot.org/show_bug.cgi?id=3454

Damien Miller <djm at mindrot.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned-bugs at mindrot.org |djm at mindrot.org
                 CC|                            |djm at mindrot.org,
                   |                            |dtucker at dtucker.net
             Status|NEW                         |ASSIGNED
   Attachment #3600|                            |ok?(dtucker at dtucker.net)
              Flags|                            |

--- Comment #1 from Damien Miller <djm at mindrot.org> ---
Created attachment 3600
  --> https://bugzilla.mindrot.org/attachment.cgi?id=3600&action=edit
ignore SIGPIPE earlier

ssh.c:main() already ignores SIGPIPE, just not early enough :(

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Darren Tucker <dtucker at dtucker.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Attachment #3600|ok?(dtucker at dtucker.net)    |ok+
              Flags|                            |

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Damien Miller <djm at mindrot.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Blocks|                            |3418
             Status|ASSIGNED                    |RESOLVED

--- Comment #2 from Damien Miller <djm at mindrot.org> ---
Patch applied and will be in OpenSSH 9.1 - thanks.


Referenced Bugs:

https://bugzilla.mindrot.org/show_bug.cgi?id=3418
[Bug 3418] tracking bug for openssh-9.1
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--- Comment #3 from noamlewis+openssh-bugzilla at google.com ---
Thanks for the very fast fix!

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Damien Miller <djm at mindrot.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #4 from Damien Miller <djm at mindrot.org> ---
Closing bugs from OpenSSH 9.1 release cycle

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