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I have a centos server that recently needed a fsck repair on it's main hard drive. After fixing a bunch of inode issues (booting from a system rescue disk), the box booted clean. Most of the services are running fine, however the sshd service immediately core dumps when I try to start it.

Running gdb /usr/sbin/sshd core.xxx, the last line before it dumps the core is:

Reading symbols from /lib/libnss_files.so.2 ... (no debugging available)
Loaded symbols for /lib/libnss_files.so.2
Core was generated by `/usr/sbin/sshd'.
Program terminated with signal 11, Segmentation fault
#0 0x00a0dffc in PEM_read_bio () from /lib/libcrpto.so.6

I've tried reinstalling sshd by (yum reinstall openssh), but no luck.

***** Update ***** I was able to get it working. In case it helps anyone else, here was the critical clue:

rpm -Va openssl prints out:

prelink: /lib/libcrypto.so.0.9.8e: prelinked file was modified
S.?...... /lib/libcrypto.so.0.9.8e

Obviously something is messed up with libcrypto (the gdb core dump also pointed to libcrypto). Looking at /lib/libcrypto* I figured out what version it was running. There is no way that I know of to have yum force reinstall the dependencies, so in the end, I had to copy the libcrypto.so.0.9.8e from another working server (using wget because scp did not work). After replacing that file, all was well.

Mircea Vutcovici
  • 19,011
John P
  • 1,739

2 Answers2

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This is a CentOS system. You were not reinstalling the entire suite. The relevant packages for OpenSSH are: openssh, openssh-server and openssh-clients. The sshd binary is part of the openssh-servers package.

Try yum reinstall openssh openssh-server openssh-clients and see if that works.

In general, to check the consistency of the packages on the system, you can use rpm verify.

rpm -vV packagename for an individual package.

or

rpm -vVa to check consistency of all installed packages.

ewwhite
  • 201,205
2

I think that one of the libraries used by sshd or may be pamlib are corrupted. Best is to check the signatures of all packages, then verify your data/configuration integrity. If you can build the system from scratch and use a fresh backup.

Mircea Vutcovici
  • 19,011