The bug KASAN: null-ptr-deref is triggered due to *val being dereferenced when it is null in fuse_copy_do() when performing memcpy(). Add a check in fuse_copy_one() to prevent this. Reported-by: syzbot+87b8e6ed25dbc41759f7@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=87b8e6ed25dbc41759f7 Fixes: 3b97c3652d91 ("fuse: convert direct io to use folios") Tested-by: syzbot+87b8e6ed25dbc41759f7@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Nihar Chaithanya <niharchaithanya@xxxxxxxxx> --- fs/fuse/dev.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 563a0bfa0e95..9c93759ac14b 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1070,6 +1070,9 @@ static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, /* Copy a single argument in the request to/from userspace buffer */ static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) { + if (!val) + return -EINVAL; + while (size) { if (!cs->len) { int err = fuse_copy_fill(cs); -- 2.34.1
