undefined symbol: pam_get_user

[brandstettermichael]

Related issue: https://github.com/gravitational/teleport/issues/3171

I'm trying to use jail-shell pam module with "Teleport" it's a SSH Gateway, when using the jail-shell pam module with it I get: PAM unable to dlopen(/lib/x86_64-linux-gnu/security/pam_jail_shell.so): /lib/x86_64-linux-gnu/security/pam_jail_shell.so: undefined symbol: pam_get_user

I tried to use ldd on the file "pam_jail_shell.so":

/lib/x86_64-linux-gnu/security# ldd -r pam_jail_shell.so 
    linux-vdso.so.1 (0x000072e1dab34000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x000072e1d9d7a000)
    /lib64/ld-linux-x86-64.so.2 (0x000072e1dab35000)
undefined symbol: pam_get_user  (./pam_jail_shell.so)
undefined symbol: pam_vsyslog   (./pam_jail_shell.so)
undefined symbol: pam_putenv    (./pam_jail_shell.so)

Check related issue for more details (like my common-session file which Teleport run).

Maybe I need to import a parent library ? I don't know what I am missing..

Your module work in normal SSH tho.

[brandstettermichael]

Doing:

LD_PRELOAD=/lib/x86_64-linux-gnu/libpam.so.0 ldd -r security/pam_jail_shell.so 
    linux-vdso.so.1 (0x000072632017f000)
    /lib/x86_64-linux-gnu/libpam.so.0 (0x000072631f564000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x000072631f1b7000)
    libaudit.so.1 => /lib/x86_64-linux-gnu/libaudit.so.1 (0x000072631ef8f000)
    libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x000072631ed8b000)
    /lib64/ld-linux-x86-64.so.2 (0x0000726320180000)
    libcap-ng.so.0 => /lib/x86_64-linux-gnu/libcap-ng.so.0 (0x000072631eb85000)

Return no errors

[brandstettermichael]

Starting teleport with LD_PRELOAD=/lib/x86_64-linux-gnu/libpam.so.0 resolve the issue. Seems like something is wrong on their side, maybe ? Like they are not loading the libpam.so.0 module.

I close the issue this doesn't seem to be related with your module ;)