observed memory leak in wpa_supplicant

[Jouni Malinen]

On Wed, Jan 27, 2016 at 10:06:32PM -0800, Naveen Singh wrote:
> We have been running some stress test of sending a deauth with reason
> code 6 and 7 from an AP to an associated client and monitoring the
> memory usage of wpa_supplicant. In our setup wpa_supplicant talks to
> connman over dbus. Running this stress test reveals memory leak in wpa
> supplicant (memory usage of wpa supplicant keeps on growing).

Have you checked that this is actually a real memory leak? For example,
run wpa_supplicant under valgrind and see whether such memory gets freed
when the process exits.

> For connection after getting disconnected connman does "AddNetwork"
> DBUS call to the previously connected SSID. This ends up causing
> memory to be allocated for struct wpa_ssid (os_zalloc called). At this
> time there is already a structure allocated for same SSID as a result
> of previous connection. Every connection ends up creating a memory
> which is never freed.

Are you sure it is not freed when wpa_supplicant process terminates? All
the added network blocks should be freed at that point in time..

> This surely causes memory usage of wpa_supplicant to go up. Should not
> we be allocating memory only if that profile (for that SSID does not
> exist?)

Memory is allocated only if a new profile is added. There can be
multiple profiles for a single SSID.

> I am talking about this function:
> struct wpa_ssid * wpa_config_add_network(struct wpa_config *config)

This needs to add a new network profile and allocate memory for it.

If you do not want more memory to be used, it is responsibility of the
program managing wpa_supplicant (either through the control interface or
through D-Bus) to re-use existing network profiles or remove profiles
they have added.

-- 
Jouni Malinen                                            PGP id EFC895FA