Commit 572c28f2 authored by Gabriel Krisman Bertazi's avatar Gabriel Krisman Bertazi Committed by Jan Kara
Browse files

fanotify: WARN_ON against too large file handles 

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.

Link: https://lore.kernel.org/r/20211025192746.66445-26-krisman@collabora.com


Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarGabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 4bd5a5c8

fs/notify/fanotify/fanotify.c

+11 −1
Original line number Diff line number Diff line
@@ -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;

}



/*