Bug#987916: openssh: Segfault or malloc_consolidate(): invalid chunk size + Aborted with GSSAPITrustDns yes
Source: openssh
Version: 1:8.4p1-5
Severity: important
Hey.
This is from https://bugzilla.mindrot.org/show_bug.cgi?id=3307:
Hey there.
I've noted the two errors, with the following setup:
Locally, I have:
OpenSSH_8.4p1 Debian-5, OpenSSL 1.1.1k 25 Mar 2021
from which I connect to some internal node at CERN (hammercloud-ai-11.cern.ch) via some publicly available node (lxplus.cern.ch) which all have:
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips 26 Jan 2017
The lxplus.cern.ch is actually a round robin DNS name, but all nodes behind have the same ssh server key.
Since CERN uses AFS, I have to do GSSAPI auth.
Locally I have a keytab file created with ktuil, which even works out of the box with SSH - that is, if I don't have a krb ticket yet, it automatically creates one.
My SSH config looks like the following:
Host hammercloud-ai-11.cern.ch
GSSAPIAuthentication yes
GSSAPIDelegateCredentials yes
GSSAPIRenewalForcesRekey yes
GSSAPITrustDns yes
ProxyJump lxplus.cern.ch
Host lxplus.cern.ch
GSSAPIAuthentication yes
GSSAPIDelegateCredentials yes
GSSAPIRenewalForcesRekey yes
GSSAPITrustDns yes
# ControlMaster auto
# ControlPersist 10s
# ControlPath ~/.ssh/channel-mux/%r@%h:%p
Host *.cern.ch
User someUser
IdentityFile ~/.ssh/id_ed25519
SetEnv "LANG=en_US.UTF-8"
Further, I do have a custom locale which is basically en_US.UTF-8, but with some international stuff like "," as decimal separator.
Now that works to login to lxplus, and from there (within an interactive session) to hammercloud-ai-11.
When I use the ProxyJump however and directly go to hammercloud-ai-11, I start to see errors.
1) with LANG=en_DE.UTF-8 it segfaults:
$ ssh hammercloud-ai-11.cern.ch -v
...
Authenticated to hammercloud-ai-11.cern.ch (via proxy).
debug1: channel 0: new [client-session]
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: pledge: proc
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug1: Sending environment.
debug1: Sending env LANG = en_DE.UTF-8
Segmentation fault
$ debug1: stdio forwarding: done
Interestingly it seems to still try to send "my" locale instead what I've configured above with:
SetEnv "LANG=en_US.UTF-8"
2) the same with LANG=C
$ export LANG=C
$ ssh hammercloud-ai-11.cern.ch -v
...
Authenticated to hammercloud-ai-11.cern.ch (via proxy).
debug1: channel 0: new [client-session]
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: pledge: proc
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug1: Sending environment.
debug1: Sending env LANG = C
malloc_consolidate(): invalid chunk size
Aborted
$ debug1: stdio forwarding: done
Whether or not using a Control Channel doesn't seem to matter.
When I comment the
Host hammercloud-ai-11.cern.ch
...
# GSSAPITrustDns yes
It works in both cases.
Commeting the same for lxplus (the proxy node), doesn't solve the issue.
Any ideas?
Cheers,
Chris.
forgot:
May 01 16:38:39 heisenberg kernel: ssh[16368]: segfault at 7e00000008 ip 00007f646525a86c sp 00007ffd72b5fb30 error 4 in libc-2.31.so[7f64651f9000+14b000]
May 01 16:38:39 heisenberg kernel: Code: 43 28 00 00 00 00 48 8b 54 24 08 48 89 ef 48 89 43 10 48 83 cf 01 48 89 7b 08 48 89 53 18 48 89 2c 2b 48 85 c9 74 87 48 89 cb <48> 8b 43 08 89 c1 c1 e9 04 83 e9 02 49 8d 4c cc 10 49 39 cd 0f 85
May 01 16:38:50 heisenberg kernel: ssh[16375]: segfault at 7e00000008 ip 00007fe602caa86c sp 00007fff2ac78150 error 4 in libc-2.31.so[7fe602c49000+14b000]
May 01 16:38:50 heisenberg kernel: Code: 43 28 00 00 00 00 48 8b 54 24 08 48 89 ef 48 89 43 10 48 83 cf 01 48 89 7b 08 48 89 53 18 48 89 2c 2b 48 85 c9 74 87 48 89 cb <48> 8b 43 08 89 c1 c1 e9 04 83 e9 02 49 8d 4c cc 10 49 39 cd 0f 85
-- System Information:
Debian Release: 11.0
APT prefers unstable-debug
APT policy: (500, 'unstable-debug'), (500, 'unstable')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-6-amd64 (SMP w/4 CPU threads)
Locale: LANG=en_DE.UTF-8, LC_CTYPE=en_DE.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
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