buildroot/package/watchdogd/0001-Fix-use-of-uninitialized-exit-status.patch

From f6d56c374723923e276ccfd442fdd0cabf23d095 Mon Sep 17 00:00:00 2001
From: Fiona Klute <fiona.klute@gmx.de>
Date: Fri, 14 Feb 2025 19:26:24 +0100
Subject: [PATCH] Fix use of uninitialized exit status

Depending on the timing between the SIGCHLD callback run and the first
generic_cb() timer callback run, script_exit_status() sometimes
returned uninitialized memory as the exit status of a script. This
could lead to incorrect "critical error" reports if that uninitialized
memory happened to contain a value that interpreted as an int was
above the critical threshold.

Additionally, script_exit_status() unconditionally removed the process
information from the queue, meaning that if a process had not
completed by the time its status was first probed, its status could
never be updated or successfully probed again, leading to timeout. Fix
this by removing the process only if the status indicates it has
terminated (successful or not).

The problems affected primarily scripts running approximately one
second or longer, because very short running scripts will very likely
have their exit status collected by the SIGCHLD callback before the
first timer callback run.

Signed-off-by: Fiona Klute <fiona.klute@gmx.de>
Upstream: https://github.com/troglobit/watchdogd/pull/52
---
 src/script.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/script.c b/src/script.c
index 1220fb9..f6e0763 100644
--- a/src/script.c
+++ b/src/script.c
@@ -16,6 +16,7 @@
  */
 
 #include <errno.h>
+#include <stdbool.h>		/* bool type (before C23) */
 #include <stdlib.h>		/* setenv() */
 #include <sys/wait.h>		/* waitpid() */
 #include <unistd.h>		/* execv(), _exit() */
@@ -28,6 +29,7 @@
 struct exec_info {
 	pid_t   pid;
 	int     exit_status;
+	bool    exited;
 	void  (*cb)(void *arg);
 	void   *arg;
 	LIST_ENTRY(exec_info) entry;
@@ -64,6 +66,8 @@ static void add(pid_t pid, void (*cb)(void *), void *arg)
 	}
 
 	info->pid = pid;
+	info->exit_status = 0;
+	info->exited = false;
 	info->cb  = cb;
 	info->arg = arg;
 	LIST_INSERT_HEAD(&exec_info_head, info, entry);
@@ -78,6 +82,7 @@ static int exec(pid_t pid, int status)
 			continue;
 
 		info->exit_status = status;
+		info->exited = true;
 		if (info->cb)
 			info->cb(info->arg);
 
@@ -96,9 +101,11 @@ int script_exit_status(pid_t pid)
 		if (info->pid != pid)
 			continue;
 
-		status = info->exit_status;
-		LIST_REMOVE(info, entry);
-		free(info);
+		if (info->exited) {
+			status = info->exit_status;
+			LIST_REMOVE(info, entry);
+			free(info);
+		}
 		break;
 	}
 
-- 
2.47.2