Bug 510478

Created attachment 351054 [details]
Proposed patch

Description of problem:

audit-1.0.15 introduced a change to interpret data withing the "msg=" filed that breaks with some messages, when the result string contains a space.

Version-Release number of selected component (if applicable):

1.0.16

How reproducible:

100% reproducible

Steps to Reproduce:
1. Install audit 1.0.16 on el4
2. try to ssh to the system with a wrong passwd to generate a PAM authentication failure 
3. ausearch -i -m USER_AUTH
  
Actual results:

----
type=USER_AUTH msg=audit(07/09/2009 00:37:22.787:13) : user pid=5098 uid=root 
auid=unset msg='PAM authentication: user=ofourdan exe=/usr/sbin/sshd 
(hostname=localhost.localdomain  addr=127.0.0.1  terminal=ssh 
result=Authentication 
----

Expected results:

----
type=USER_AUTH msg=audit(07/09/2009 00:37:22.787:13) : user pid=5098 uid=root 
auid=unset msg='PAM authentication: user=ofourdan exe=/usr/sbin/sshd 
(hostname=localhost.localdomain, addr=127.0.0.1, terminal=ssh 
result=Authentication failure)' 
----

Additional info:

The problem was comes from output_interpreted_node() in ausearch-report.c.

The addition of:

    147 static void output_interpreted_node(const lnode *n)
    148 {
    [...]

    226         // for each item.
    227         while (str && *str && (ptr = strchr(str, '='))) {
    [...]

    240                 // Some user messages have msg='uid=500   in this case
    241                 // skip the msg= piece since the real stuff is the uid=
    242                 if (strcmp(name, "msg") == 0) {
    243                         str = ptr;
    244                         continue;
    245                 }
    [...]

Introduced a breakage when looking for the the end of the line a few lines later in the code:

    251                 // get string after = to the next space or end - this is value
    252                 if (*ptr == '\'' || *ptr == '"') {
    253                         str = strchr(ptr+1, *ptr);
    254                         if (str) {
    255                                 str++;
    256                                 if (*str)
    257                                         *str++ = 0;
    258                         } 
    259                 } else {
    260                         str = strchr(ptr, ',');
    261                         val = strchr(ptr, ' ');
    262                         if (str && val && (str < val)) {
    263                                 *str++ = 0;
    264                                 comma = 1;
    265                         } else if (str && (val == NULL)) {
    266                                 *str++ = 0;
    267                                 comma = 1;
    268                         } else if (val) {
    269                                 str = val;
    270                                 *str++ = 0;
    271                         }
    272                 }

Because the "'" is skipped before. As a result, the search for the separator truncated the last portion of the message in there is an space or a comma in the last part of the message (like in "result=Authentication failure)'")

The attached patch tries to address the problem by looking ahead for more fields to parse (ie more "=") and looks for the separator only if there are more fields, thus avoiding the truncation of the last portion of the message.

Note: The problem is most likely present also upstream and in el5 as the code is similar.