Re: PROBLEM: fanotify_mark EFAULT on x86

From: Paweł Jasiak
Date: Tue Nov 03 2020 - 16:18:19 EST


I have written small patch that fixes problem for me and doesn't break
x86_64.

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 3e01d8f2ab90..cf0b97309975 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1285,12 +1285,27 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
return ret;
}

+#if defined(CONFIG_X86) && !defined(CONFIG_64BIT)
+SYSCALL_DEFINE6(fanotify_mark,
+ int, fanotify_fd, unsigned int, flags, __u32, mask0,
+ __u32, mask1, int, dfd, const char __user *, pathname)
+{
+ return do_fanotify_mark(fanotify_fd, flags,
+#ifdef __BIG_ENDIAN
+ ((__u64)mask0 << 32) | mask1,
+#else
+ ((__u64)mask1 << 32) | mask0,
+#endif
+ dfd, pathname);
+}
+#else
SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags,
__u64, mask, int, dfd,
const char __user *, pathname)
{
return do_fanotify_mark(fanotify_fd, flags, mask, dfd, pathname);
}
+#endif

#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE6(fanotify_mark,


--

Paweł Jasiak