Bug ID 680972: Hidden newlines within monitor parameters may silently load without error

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP TMOS(all modules)

Known Affected Versions:
11.5.4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 11.6.0, 11.6.1, 11.6.2, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 11.6.5.1, 11.6.5.2, 11.6.5.3

Opened: Aug 30, 2017

Severity: 3-Major

Related Article: K73425254

Symptoms

Monitor parameters containing hidden newlines may silently load without error, when the configuration should fail to load. A conforming configuration requires each monitor parameter to comprise a single line; but manually editing the configuration file may insert a line-break within a single monitor parameter, thus breaking the parameter across two lines (resulting in a non-conforming definition). If the first line has an odd number of double-quotes (regardless of the presence of backslash-escaping), the hidden newline will not be detected and the monitor will load successfully.

Impact

The configuration loads successfully, when it should be rejected as non-conforming. The monitor will function normally, as the two lines separated by the hidden newline will be merged upon load. The configuration will behave correctly, even though the hidden line break implies the file is non-conforming.

Conditions

A configuration file where a single monitor parameter is broken across two text lines (such as after manually editing the text file), and where the first line has an odd-number of double-quotes (regardless of the presence of backslash-escaping). For example, an improper text line break within a single monitor configuration that silently loads: 'send "GET http://path={\"checkDatabase\":\"true\"}<CR>\r\n"' ...where "<CR>" represents the hidden line break in the text file. This silently loads because the odd-number of double-quotes on the first line (before the <CR>) hides the newline in the text file, resulting in the first line being merged with the second line upon configuration load.

Workaround

Modify the configuration file so that each monitor parameter comprises a single text line (which is required for a conforming configuration).

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips