Hello Debian Networking Team,
We independently identified and fixed the same issue in netplug 1.2.9.2-5
while investigating network recovery failures in SKUDONET virtual machines.
I originally emailed Pali Rohár on 19 May 2026 and followed up on 29
September, before becoming aware of this existing bug report.
The problem is in find_pid(), as modified by
debian/patches/70no-executable-stack.patch:
pid_t pid = *(pid_t *)(((void **)arg)[0]);
struct if_info **info = (struct if_info **)(((void **)arg)[0]);
The caller supplies:
arg[0] = &pid;
arg[1] = &info;
Therefore, the second expression must use arg[1]. With the current code,
*info = i writes an interface pointer into the storage occupied by pid,
corrupting the PID and potentially adjacent stack memory. The actual
interface pointer remains NULL, so ifsm_scriptdone() returns without
processing the script completion.
We observed:
Unexpected child -629697296 exited with status 0
This leaves the interface state machine unable to complete the expected
transition, even though the script exited successfully.
The one-line fix is:
--- a/if_info.c
+++ b/if_info.c
@@ -317,7 +317,7 @@ void ifsm_scriptdone(pid_t pid, int exitstatus)
int find_pid(struct if_info *i, void *arg) {
pid_t pid = *(pid_t *)(((void **)arg)[0]);
-
struct if_info **info = (struct if_info **)(((void **)arg)[0]);
-
struct if_info **info = (struct if_info **)(((void **)arg)[1]);
if (i->worker == pid) {
*info = i;
We rebuilt the Trixie 1.2.9.2-5 source for a Debian Buster-based SKUDONET
installation with this correction. The affected customer confirmed that
recovery after Hyper-V live/quick migration worked with the corrected
package.
Source inspection also confirms that the incorrect index remains in Debian
revision 1.2.9.2-7.
Could you please incorporate this correction and consider a stable update
for Trixie? It fixes a memory corruption bug that prevents normal handling
of completed network event scripts.
Thank you.
Best regards,
Emilio Campos Martín
SKUDONET
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