If a filesystem returns negative inode sizes,
future reads on the file were causing the cpu
to spin on truncate_pagecache. This seems like
invalid behaviour as a buggy / malicious
filesystem can cause a lockup.
This patch checks for negative sizes before
truncating the page cache.
Signed-off-by: Arijit Banerjee <arijit@xxxxxxxxxx>
---
fs/fuse/inode.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 1b3f3b6..5744d16 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -236,7 +236,9 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
bool inval = false;
if (oldsize != attr->size) {
- truncate_pagecache(inode, attr->size);
+ if ((off_t)attr->size >= 0)
+ truncate_pagecache(inode, attr->size);
+
inval = true;
} else if (fc->auto_inval_data) {
struct timespec64 new_mtime = {
--
1.9.1
