struct fanotify_error_event, at least, is preallocated and isn't able to
to handle arbitrarily large file handles. Future-proof the code by
complaining loudly if a handle larger than MAX_HANDLE_SZ is ever found.
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
---
fs/notify/fanotify/fanotify.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index cedcb1546804..45df610debbe 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -360,13 +360,23 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
static int fanotify_encode_fh_len(struct inode *inode)
{
int dwords = 0;
+ int fh_len;
if (!inode)
return 0;
exportfs_encode_inode_fh(inode, NULL, &dwords, NULL);
+ fh_len = dwords << 2;
- return dwords << 2;
+ /*
+ * struct fanotify_error_event might be preallocated and is
+ * limited to MAX_HANDLE_SZ. This should never happen, but
+ * safeguard by forcing an invalid file handle.
+ */
+ if (WARN_ON_ONCE(fh_len > MAX_HANDLE_SZ))
+ return 0;
+
+ return fh_len;
}
/*
--
2.33.0
