fix duplicate PAM msgs, missing loginmsg reset #522
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without this change in mm_answer_pam_account all messages added in auth-pam.c sshpam_query(...) case PAM_SUCCESS end up sent here, then are still sitting in the loginmsg buffer and printed a second time in session.c do_login(...)
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Without this change in mm_answer_pam_account all messages added in auth-pam.c sshpam_query(...)
case PAM_SUCCESSend up sent here, then are still sitting in the loginmsg buffer and printed a second time in session.c do_login(...)I initially encountered this problem using
pam_duo.so(described by some other user in the link below) however it is not specific to that PAM module, I also get messages printed twice when pam_echo.so, pam_debug.so, and others are included in the auth PAM chain used by sshd.https://community.cisco.com/t5/protecting-applications/duplicate-success-logging-you-in-after-a-successful-login/td-p/4879911
Without this code change, given the logic inside do_login(...) it is possible to work-around the problem on per-user basis with
touch ~/.hushloginbut that also has the side-effect of disabling printing of the MOTD by sshd if that is configured ...and it is per-user not system-wide.I gave some thought to whether there is any circumstance where the behavior of the original code is desired but thus far I cannot imagine one, although I am not deeply familiar with OpenSSH codebase.