From 3ad490ea48468e50fe91f6f6b2ca4cbc74d924bf Mon Sep 17 00:00:00 2001
From: Aleksandr Nogikh <nogikh@google.com>
Date: Mon, 18 Dec 2023 11:58:39 +0100
Subject: executor: introduce syz_pidfd_open()

This kernel interface provides access to fds of other processes, which
is readily abused by the fuzzer to mangle parent syz-executor fds.

Pid=1 is the parent syz-executor process when PID namespace is created.
Sanitize it in the new syz_pidfd_open() pseudo-syscall.

We could not patch the argument in sys/linux/init.go because the first
argument is a resource.
---
 pkg/csource/generated.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'pkg/csource/generated.go')

diff --git a/pkg/csource/generated.go b/pkg/csource/generated.go
index 4c3fae47c..e65b95095 100644
--- a/pkg/csource/generated.go
+++ b/pkg/csource/generated.go
@@ -11823,6 +11823,18 @@ static void setup_swap()
 
 #endif
 
+#if SYZ_EXECUTOR || __NR_syz_pidfd_open
+#include <sys/syscall.h>
+static long syz_pidfd_open(volatile long pid, volatile long flags)
+{
+	if (pid == 1) {
+		pid = 0;
+	}
+	return syscall(__NR_pidfd_open, pid, flags);
+}
+
+#endif
+
 #elif GOOS_test
 
 #include <stdlib.h>
-- 
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