Commit 3066ff93 authored by Bernd Schubert's avatar Bernd Schubert Committed by Miklos Szeredi
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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: default avatarBernd Schubert <bschubert@ddn.com>
Fixes: 53db2893 ("fuse: extend init flags")
Cc: <stable@vger.kernel.org> # v5.17
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 1c3610d3

fs/fuse/inode.c

+4 −1
Original line number Diff line number Diff line
@@ -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)