From 3066ff93476c35679cb07a97cce37d9bb07632ff Mon Sep 17 00:00:00 2001 From: Bernd Schubert Date: Fri, 15 Apr 2022 13:53:56 +0200 Subject: fuse: Apply flags2 only when userspace set the FUSE_INIT_EXT This is just a safety precaution to avoid checking flags on memory that was initialized on the user space side. libfuse zeroes struct fuse_init_out outarg, but this is not guranteed to be done in all implementations. Better is to act on flags and to only apply flags2 when FUSE_INIT_EXT is set. There is a risk with this change, though - it might break existing user space libraries, which are already using flags2 without setting FUSE_INIT_EXT. The corresponding libfuse patch is here https://github.com/libfuse/libfuse/pull/662 Signed-off-by: Bernd Schubert Fixes: 53db28933e95 ("fuse: extend init flags") Cc: # v5.17 Signed-off-by: Miklos Szeredi --- fs/fuse/inode.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'fs/fuse') diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 660be31aaabc..f19d748890f0 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1134,7 +1134,10 @@ static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, process_init_limits(fc, arg); if (arg->minor >= 6) { - u64 flags = arg->flags | (u64) arg->flags2 << 32; + u64 flags = arg->flags; + + if (flags & FUSE_INIT_EXT) + flags |= (u64) arg->flags2 << 32; ra_pages = arg->max_readahead / PAGE_SIZE; if (flags & FUSE_ASYNC_READ) -- cgit v1.2.3