Bug 474160 - pam_abl doesn't record successive failed attempts within a single ssh connection
pam_abl doesn't record successive failed attempts within a single ssh connection
Product: Fedora
Classification: Fedora
Component: pam_abl (Show other bugs)
i386 Linux
low Severity medium
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Assigned To: Alexander Dalloz
Fedora Extras Quality Assurance
Depends On:
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Reported: 2008-12-02 10:27 EST by Thibault LE MEUR
Modified: 2009-12-18 02:06 EST (History)
3 users (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2009-12-18 02:06:00 EST
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Description Thibault LE MEUR 2008-12-02 10:27:40 EST
Description of problem:
When using pam_abl in conjuction with openssh, a user can try to authenticate several times in the same ssh connection. Failing to login will only be counted as 1 failed authentication attempt instead of the 6 (default) failed attempts.

Version-Release number of selected component (if applicable):
pam_abl 0.2.3-6.fc10
openssh-server 5.1p1-3.fc10

How reproducible:

Steps to Reproduce:
1. install pam_abl and openssh-server and set up pam_abl
2. initiate an ssh connection (I'm using putty)
3. try to authenticate as a user with a wrong password
4. loop step 3 until the connection is closed because of too many failed attempts  (by default should be 6)

Actual results:
* look at the pam_abl database status: only 1 failed attempt is recorded

Expected results:
* 6 failed attempts should have been recorded to pam_abl DB.

Additional info:
* this bug was related to a bug in openssh which has been fixed in 4.7p3 I think (at least it is fixed in 4.8)

* the other part of the bug is due to a missing fix in pam_abl
"also record attempts on consecutive auth tries" see (http://pam-abl.svn.sourceforge.net/viewvc/pam-abl?view=rev&revision=13)

* The fix applies cleanly on the pam_ldap.c file after all fixes included in current SRPM.

I can report that after applying the fix, pam_abl works as expected:

--- pam_abl.c	2007/10/03 10:42:16	12
+++ pam_abl.c	2007/10/03 21:14:48	13
@@ -356,10 +356,15 @@
 PAM_EXTERN int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv) {
     abl_args *args;
-    int err = PAM_SUCCESS;
+    const void *prev_args;
+    int err;
     /*log_debug(NULL, "pam_sm_authenticate(), flags=%08x", flags);*/
+    if (pam_get_data(pamh, DATA_NAME, &prev_args) == PAM_SUCCESS) {
+        record_attempt(prev_args);
+    }
     if (args = malloc(sizeof(abl_args)), NULL == args) {
         return PAM_BUF_ERR;

Comment 1 Bug Zapper 2009-11-18 05:16:14 EST
This message is a reminder that Fedora 10 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
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bug reports from releases that are no longer maintained.  At that time
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Comment 2 Bug Zapper 2009-12-18 02:06:00 EST
Fedora 10 changed to end-of-life (EOL) status on 2009-12-17. Fedora 10 is 
no longer maintained, which means that it will not receive any further 
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